lap trinh c tren windows 5536

NGN NG LP TRNH WINDOWS

LP TRNH c TRN

LP TRNH c TRN WINDOWS

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NGN NG LP TRNH LP TRNH c TRNWINDOWS

Chng 1

TNG QUAN LP TRNH c TRN WINDOWS

1.1. M U

lp trnh trn Microsoft Windows, chng ta cn nm c cc c im c bn nht ca h iu hnh ny. Chng ny s gii thiu khi qut cc c im h iu hnh Microsoft Windows, cc vn lin quan n lp nh bng ngn ng c, ng thi a ra mt chng trnh mu lm sn cho cc chng trnh c vit sau ny.

Trong phn u, chng ta tm hiu s lc lch s pht trin ca h iu hnh Microsoft Windows v nhng c im nn tng ca Windows.

Phn tip theo s trnh by nhng khi nim v yu cu cn bn ca vic lp trnh c trn Windows. Ngoi ra, phn ny cng gii thiu cc c ch v cc cng c m h iu hnh cung cp cho ngi lp trnh hay ngi pht in cc ng dng trn Windows.

Cui chng l phn xy dng mt chng trnh n gin nht trn Windows. Chng trnh ny c xem nh l khun mu ca mt chng nh ng dng in hnh, v hu ht cc on chng trnh c vit minh ha trong sch u ly chng nh ny lm khung sn pht trin cho ph hp vi tng yu cu. Thm vo , mt s kiu d liu mi c nh ngha trn Windows v nhng qui c v cch t tn bin cng c gii thiu trong phn ny.

Phn chi tit v chuyn su hn ca vic lp trnh bng ngn ng c trn mi trng Windows s c trnh by trong cc chng tip theo.

1.2. H IU HNH MICROSOFT WINDOWS

1.2.1. Gii th iu

Gia thp nin 80, cng ty phn mm my tnh Microsoft cng b phin bn u tin ca dng h iu hnh Windows l Microsoft Windows 1.0. y l h iu hnh dng giao din ha khc vi giao din k t (text hay console) ca MS-DOS. Tuy nhin phi n phin bn th hai (Windows 2.0 - thng 11 nm 1987) th mi c bc ci tin ng k, l s m rng giao tip gia bn phm v thit b chut v giao din ha (GVl-Graphc User Interface) nh trnh n (menu) v hp thoi (dialog). Trong phin bn ny Windows ch yu cu b vi x l Intel 8086 hay 8088 chy real-mode truy xut 1 megabyte b nh.

Thng 5 nm 1990, Microsoft cng b phin bn tip theo l Windows 3.0. s thay i ln trong phin bn ny l Windows 3.0 h tr protected-mode 16 bit ca cc b vi x l 286, 386, v 486 ca Intel, s thay i ny cho php cc hg dng trn Windows truy xut 16 megabyte b nh. Tip bc vi s pht trin l phin bn Windows 3.1 ra i nm 1992, Microsoft a cng ngh Font TrueType, m nhc (multimedia), lin kt v nhng i tng (OLE- Object Linking and Embedding), v a ra cc hp thoi chung c chun ha.

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Trong s pht in mnh m ca nhng thp nin 90, Microsoft cng b tip dng h iu hnh Windows vi ng dng cng ngh mi (1993). H iu hnh ny ly tn l Windows NT (Windows New Technology), y l phin bn h iu hnh u tin ca Windows h tr 32 bit cho b x l 386, 486 v Pentium. Trong h iu hnh ny th cc ng dng phi truy xut b nh vi a ch l 32-bit v cc tp lnh hay ch th 32-bit. Ngoi ra Windows NT cng c thit k chy cc b vi x l (CPU) khc ngoi Intel v c th chy trn cc my trm (workstation).

H iu hnh Windows 95 c cng b nm 1995 cng l mt h iu hnh 32-bit cho Intel 386 tr v sau. Tuy thiu tnh bo mt nh Windows NT v vic thch nghi vi my trm cng ngh RISC, nhng b li h iu hnh ny yu cu phn ctig khng cao.

Song song vi s pht trin phn mm th cng ngh phn cng cng pht trin khng km. tn dng sc mnh ca phn cng th cc th h Windows tip theo ngy cng hon thin hn. Nh Windows 98 pht trin t Window 95 v c nhiu ci thin nh hiu nng lm vic, h tr cc thit b phn eifrig tt hn, v cui cng l vic tch hp cht ch vi Internet v Word Wide Web.

Windows 2000 l h iu hnh c xem l n nh v tt ca dng Windows, phin bn ny tng cng cc tnh nng bo mt thch hp trong mi trng mng v giao din p.

1.2.2. c im chung ca h iu hnh Microsoft Windows

Windows l mt h iu hnh s dng giao tip ngi dng ha (GUI), hay cn gi l h iu hnh trc quan (Visual interface). GUI s dng ha da trn mn hnh nh nh phn (Bitmapped video display). Do tn dng c ti nguyn thc ca mn hnh, v cung cp mt mi trng giu tnh trc quan v sinh ng.

Windows khng n iu nh MS-DOS (hay mt s h iu hnh giao din console) m mn hnh c s dng ch th hin chui k t, do ngi dng g t bn phm (keyboard) hay xut thng tin dng vn bn. Trong giao din ngi dng ha, mn hnh giao tip vi ngi s dng a dng hn, ngi dng c th nhp d liu thng qua chut bng cch nhn vo cc nt nhn (button) cc hp chn (combo box) ...thit b by gi c nhp, c th l bn phm v thit b chut (mouse device). Thit b chut l mt thit b nh v trn mn hnh, s dng thit b chut ngi dng c th nhp d liu mt cch trc quan bng cch kch hot mt nt lnh, hay lm vic vi cc i tng ha lin quan n ta txn mn hnh.

giao tip trong mi trng ha, Windows a ra mt s cc thnh phn gi l cc iu khin chung (common control), cc iu khin chung l cc i tng c a vo trong hp thoi giao tip vi ngi dng. Bao gm : hp vn bn (text box), nt nhn (button), nt chn (check box), hp danh sch (list box), hp chn (combo box)...

Tht ra mt ng dng trn Windows khng phi l qu phc tp v chng c hnh thc chung. Chng trnh ng dng thung chim mt phm vi hnh ch nht trn mn hnh gi l mt ca s. Trn cng ca mi ca s l thanh tiu (title bar). Cc chc nng ca chng

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NGN NG LP TRNH LP TRNH c TRNWINDOWStrnh th c lit k trong thc n la chn ca chng trnh (menu), hay xut hin di dng trc quan hn l cc thanh cng c (toolbar). Cc thanh cng c ny cha cc chc nng c s dng thng xuyn ong thc n gim thi gian cho ngi dng phi m thc n v chn. Thng thng khi cn ly thng tin hay cung cp thng tn cho ngi dng thi mt ng dng s a ra mt hp thoi, trong hp thoi ny s cha cc iu khin chung giao tip vi ngi dng. Windows cng ra to mt s cc hp thoi chun nh Open Files, v mt s hp thoi tng t nh nhau.

Windows l mt h iu hnh a nhim, ty thuc vo b nh m ta c th chy nhiu ng dng cng mt lc, v cng c th ng thi chuyn qua li gia cc ng dng v thc thi chng. Trong cc phin bn ca Windows 98 v NT tr v sau, cc chng trnh ng dng t bn thn chng chia thnh nhiu tiu trnh (thread) x l v vi tc x l nhanh to cm gic nhng chng trnh Lftig dng ny chy ng thi vi nhau.

Trong Windows, chng trnh ng dng khi thc thi c chia s nhhg th tc m Windows cung cp sn, cc tp tn cung cp nhTag th tc n c gi l th vin lin kt ng (Dynamic Link Libraries - DLL). Windows c c ch lin kt nhng chng trnh ng dng vi cc th tc c cung cp trong th vin lin kt ng.

Kh nng tng thch ca Windows cng rt cao. Cc chng trnh ng dng c vit cho Windows khng truy xut trc tip phn cng ca nhhg thit b ho nh mn hnh v my in. M thay vo , h iu hnh cung cp mt ngn ng lp trnh ha (gi l Giao tip thit b ho - Graphic Device Interface - GDI) cho php hin th nhng i tng ha mt cch d dng. Nh vy mt ng dng vit cho Windows s chy vi bt c thit b mn hnh no hay bt k my in, min l ci t trnh iu khin thit b h tr cho Windows. Chng trnh ng dng khng quan tm n kiu thit b kt ni vi h thng.

Nh gii thiu phn trn khi nim lin kt ng l thnh phn qnan trng ra Windows, n c xem nh l ht nhn ca h iu hnh, v bn thn ca Windows l cc tp th vin lin kt ng. Windows cung cp rt nhiu hm cho nhng chng trnh ng dng ci t giao din ngi dng v hin th vn bn hay ha trn mn hnh. Nhhg hm ny c ci t trong th vin lin kt ng hay cn gi l DLL. l cc tp tin c dng phn m rng l *.DLL hay *.EXE, hu ht c cha trong th mc \Windows\System, \Windows\system32 ca Windows 98 v cc th mc \WinNT\System, \WinNT\System32 ca Windows NT.

Trong cc phin bn sau ny, h thng lin kt ng c to ra rt nhiu, tuy nhin, hu ht cc hm c gi trong th vin ny phn thnh 3 n v sau: Kernel, User, v GDI.

Kernel cung cp cc hm v th tc m mt ht nhn h iu hnh truyn thng qun l, nh qun l b nh, xut nhp tp tin v tc v. Th vin ny c ci t trong tp tin KRNL386.EXE 16 bit v KERNEL32.DLL 32 bit!

User qun l giao din ngi dng, ci t tt c khung ca s mc lun l. Th vin User c ci t trong tp n USER.EXE 16 bit v USER32.DLL 32 bit.

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GDI cung cp ton b giao din thit b ho (Graphics Device Interface), cho php chng trnh ng dng hin th vn bn v ho trn cc thit b xut phn cng nh mn hnh v my in.

Trong Windows 98, th vin lin kt ng cha khong vi ngn hm, mi hm c tn c t, v d CreateWindow, hm ny dng to mt ca s cho ng dng. Khi s dng cc hm m Windows cung cp cho th cc ng dng phi khai bo trong cc tp tn tiu .h hay .hpp (header file).

Trong mt chng trnh Windows, c s khc bit khi ta gi mt hm ca th vin c v mt hm ca Windows hay th vin lin kt ng cung cp. l khi bin dch m my, cc hm th vin c s c lin kt thnh m chng trnh. Trong khi cc hm Windows s c gi khi chng trnh cn dng n ch khng lin kt vo chng nh. thc hin c cc li gi ny th mt chng nh Windows *.EXE lun cha mt tham chiu n th vin lin kt ng khc m n cn dng. Khi , mt chng trnh Windows c np vo b nh s to con tr tham chiu n nhng hm th vin DLL m chng nh dng, nu th vin ny cha c np vo b nh trc th by gi s c np.

1.3. LP TRNH TRN MICROSOFT WINDOWS

1.3.1. c im chung

Windows l h iu hnh ha trc quan, do d cc ti nguyn ca h thng cung cp rt a dng i hi ngi lp nh phi nghin ca rt nhiu pht hay ht sc mnh ca h iu hnh.

Theo nh nhng mc ch tip cn ca cc nh lp trnh th cc ng dng trn Windows phi ht sc thn thin vi ngi dng thng qua giao din ha sn c ca Windows, v l thuyt th mt ngi dng lm vic c vi mt hg dng ca Windows th c th lm vic c vi nhng ng dng khc. Nhuhg trong thc t s dng mt hg dng cho t hiu qu cao trong Windows th cn phi c mt s hun luyn tr gip hay ti thiu th phi cho bit chng trnh ng dng lm vic nh th no.

a s cc ng dng trong Windows u c chung mt giao din tng tc vi ngi dng ging nhau. V d nh cc ng dng trong Windows a s u c thanh thc n cha cc mc n h : File, Edit, Tool, Help... V trong hp thoi th thng cha cc phn t iu khin chung nh: Edit Control, Button Control, Checkbox....

1.3.2. S khc b i t vi lp trnh trn MS-DOS

Khi mi bc vo lp trnh trn Windows a s ngi hc rt l lm, nht l nhng ngi tng lm vic vi MS-DOS. Do MS-DOS l h iu hnh n nhim v giao tip qua giao din console. Nn khi vit chng trnh khng phc tp.

Cn i vi Windows ngi lp trnh s lm vic vi b cng c lp trnh ha a dng cng vi cch x l a nhim, a lung ca Windows. V vy vic lp trnh trn Windows s gip cho ngi lp trnh nhm chn vi giao din console ca MS-DOS. Vic

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NGN NG LP TRNH LP TRNH c TRNWINDOWSc gng pht huy cc sc mnh ti nguyn ca Windows s lm cho nhng ng dng cng mnh m, a dng, thn thin, v d s dng.

1.3.3. M t s yu cu i vi ngi lp trnh

iu trc tin ca ngi hc lp trnh c trn Windows l phi bit lp trnh c , sch ny khng c tham vng hng dn ngi hc c th thng tho lp trnh c trn Windows m cha qua mt lp hun luyn c no. Tuy nhin, khng nht thit phi hon ton thng tho c mi hc c lp trnh Windows.

c th lp trnh n nn Windows ngoi yu cu v vic s dng cng c lp trnh, ngi hc cn cn phi c cn bn v Windows, ti thiu th cng dng qua mt s ng dng trong Windows. Tht s yu cu ny khng qu kh khn i vi ngi hc v hin ti hu nh Windows qu quen thuc vi mi ngi, nhng ngi m s dng my tnh.

Ngoi nhng yu cu n, i khi ngi lp trnh n Windows cng cn c khiu thm m, v cch trnh by cc hnh nh, cc iu khin trn cc hp thoi tt th s lm cho ng dng cng tin li, r rng, v thn thin vi ngi dng.

1.3.4. B cng c giao d in lp trnh ng dng API

H iu hnh Windows cung cp hng m hm cho nhng ng dng c th s dng truy cp cc ti nguyn trong h thng. Nhng hm ny c gi l giao din lp trnh ng dng API (Application Programming Interface). Nhng hm trn c cha trong cc th vin lin kt ng DLL ca h thng. Nh c cu trc ng ny mi ng dng u c th truy cp n cc hm . Khi bin dch chng trnh, n on m gi hm API th chng trnh dch khng thm m hm ny vo m thc thi m ch thm tn DLL cha hm v tn ca chnh hm . Do m cc hm API thc t khng c s dng khi xy dng chng trnh, v n ch c thm vo khi chng trnh c np vo b nh thc thi.

Trong API c mt s hm c chc nng duy s c lp thit b ha, v cc hm ny gi l giao din thit b ha GDI (Graphics Device Interface). Do s c lp thit b nn cc hm GDI cho php cc ng dng c th lm vic tt vi nhiu kiu thit b ha khc nhau.

1.3.5. C ch thng ip

Khng ging nh cc ng dng chy trn MS-DOS, cc ng dng Win32 th x l theo cc s kin (event - driven), theo c ch ny cc ng dng khi c vit s lin tc ch cho h iu hnh truyn cc d liu nhp vo. H thng s m nhim vic truyn tt c cc d liu nhp ca ng dng vo cc ca s khc nhau ca ng dng . Mi mt ca s s c ring mt hm gi l hm x l ca s thng c t tn l WndProc, h thng s gi hm ny khi c bt c d liu nhp no c truyn n ca s, hm ny s x l cc d liu nhp v tr quyn iu khin v cho h thng.

H thng truyn cc d liu nhp vo th tc x l ca ca s thng qua mt hinh thc gi l thng ip (message). Thng ip ny c pht sinh t ng dng v h thng.

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NGN NG LP TRNH LP TRNH c TRNWINDOWSH thng s pht sinh mt thng ip khi c mt s kin nhp vo (input even), v d nh khi ngi dng nhn mt phm, di chuyn thit b chut, hay kch vo cc iu khin (control) nh thanh cun,... Ngoi ra h thng cng pht sinh ra thng ip phn 1ng li mt s thay i ca h thng do mt ng dng mang n, iu ny xy ra khi ng dng lm cn kit ti nguyn hay ng dng t thay i kch thc ca ca s.

Mt ng dng c th pht sinh ra thng ip khi cn yu cu cc ca s ca n thc hin mt nhim v no hay dng thng tin gia cc ca s.

H thng gi thng ip vo th tc x l ca s vi bn tham s: nh danh ca ca s, nh danh ca thng ip, v hai tham s cn li c gi l tham s ca thng ip (message parameters). nh danh ca ca s xc nh ca s m thng ip c ch nh. H thng s dng nh danh ny xc nh cn phi gi thng ip n th tc x l ca ca s.

nh danh thng ip l mt hng s th hin mc ch ca thng ip. Khi th tc x l ca s nhn thng ip th n s dng nh danh ny bit hnh thc cn thc hin.V d, khi mt thng ip c truyn n th tc ca s c nh danh l WM_PAINT th c ngha rng ca s vng lm vic thay i v cn phi v li vng ny.

Tham s thng ip lu gi hay v ca d liu, c dng bi th tc ca s khi x l thng ip. Tham s ny ph thuc vo loi thng ip c truyn n, n c th l s nguyn, mt tp cc bit dng lm c hiu, hay mt con n mt cu trc d liu no ,...

Khi mt thng ip khng cn dng n tham s th h thng s thit lp cc tham s ny c gi tr NULL. Mt th tc ca s phi kim tra xem vi loi thng ip no cn dng tham s quyt nh rch s dng rc tham s ny.

C hai loi thng ip :

Thng ip c nh ngha bi h thng (system-defined messages):

Dng thng ip ny c h thng nh ngha cho cc ca s, cc iu khin, v cc ti nguyn khc ong h thng. Thng c bt u vi cc tin t sau : WM_XXX,LB xxx, CB xxx,...

Thng ip c nh ngha bi ng dng (application-defined message) :

Mt ng dng c th to ring cc thng ip s dng bi nhhg ca s ca n hay truyn thng tin gia cc ca s trong ng dng.

Nu mt ng dng nh ngha cc thng ip ring th th tc ca s nhn c thng ip ny phi cung cp cc hm x l tng ng.

i vi thng ip h thng, th c cung cp gi tr nh danh t 0x0000 n 0x03FF, nhng ng dng khng c nh ngha thng ip c gi trong khong ny.

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Thng ip c ng dng nh ngha c gi tr nh danh t 0x0400 n 0x7FFF.

L trnh ca thng ip t lc gi i n lc x l c hai dng sau:

Thng ip c gi vo hng i thng ip ch x l (queue message): bao gm cc kiu thng ip c pht sinh t bn phm, chut nh thng ip : WM_MOUSEMOVE, WM_LBUTTONDOWN, WMJKEYDOWN, v WM CHAR.

Thng ip c gi trc tip n th tc x l khng qua hng i (nonqueue message), bao gm cc thng ip thi gian, thng ip v, v thng ip thot nh WM_TIMER, WMJPAINT, va WMLQUIT.

x l thng ip : Mt ng dng phi xa v x l nhng thng ip c gi ti hng i ca ng dng . i vi mt ng dng n tiu tnh th s dng mt vng lp thng ip (message Innp) trong hm WinMain nhn thng ip t hng i v gi ti th tc x l ca s tng ng. v i nhng ng dng nhiu tiu trnh th mi mt tiu trnh c to ca s th s c mt vng lp thng ip x l thng ip ca nhng ca s trong tiu trnh .

1.4. CCH VIT M T NG DNG TRN MICROSOFT WINDOWS

1.4.1. Cc thnh ph n c b n to nn m t ng dng

1.4.1.1. c a s

Trong mt Lftig dng ha 32-bit, ca s (window) l mt vng hnh ch nht n mn hnh, ni m Lftig dng c th hin th thng tin ra v nhn thng tin vo t ngi s dng. Do vy, nhim v u tin ca mt ng dng ha 32-bit l to mt ca s.

Mt ca s s chia s mn hnh vi cc ca s khc trong cng mt Lftig dng hay cc ng dng khc. Ch mt ca s trong mt thi im nhn c thng tin nhp t ngi dng. Ngi s dng c th dng bn phm, thit b chut hay cc thit b nhp liu khc tng tc vi ca s v ng dng.

Tt c cc ca s u c to t mt cu trc c cung cp sn gi l lp ca s (window class), c u trc ny l mt tp m t cc thuc tnh m h thng dng nh khun mu to nn cc ca s. Mi mt ca s phi l thnh vin ca mt lp ca s. Tt c cc lp ca s ny u c x l ring bit.

1.4.1.2. Hp thoi v cc iu khin

Hp thoi (Dialog) dng tng tc vi ngi dng trong mt chng trnh ng dng. Mt hp thoi thng cha nhiu cc u khin nh nhp vn bn (edit text), nt bm (button), ghi ch (static control), hp danh sch ist box)...

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> Nt bm (button): gm c Push Button dng kch hot mt thao tc, Check Box dng chn mt ong hai trng thi (TRUE hay FALSE), Radio Button cng ging nh Check Box nhng mt nhm cc Radio Button phi c chn loi tr nhau.

> Ch thch (static): dmg cha cc ghi ch trong hp thoi, ngoi ra ni dung c th thay i trong qu trinh s dng hp thoi.

> H p li t k (list box): Chn mt hay nhiu d liu c lit k trong danh sch, nu hp cha nhiu dng v hp khng hin th ht cc mu thng tin th phi km theo mt thanh cun (scroll bar).

> nhp vn bn (edit text): Dng nhp vn bn, nu c nhiu dng th thng km theo thanh cun.

> Thanh cun (scroll bar): ngoi vic dng km vi list box hay edit box th thanh cun cn c th s dng c lp nhm to cc thc o...

> Thc n (menu): l mt danh sch cha cc thao tc vi mt nh danh m ngi dng c th chn. Hu ht cc ng dng c ca s th khng th thiu thc n.

> Thanh cng c (toolbar): y l mt dng menu nhng ch cha cc thao tc cn thit di dng cc biu tng c trng.

Ngoi ra cn rt nhiu cc iu khin m cc cng c lp nh cung cp cho ngi lp trnh hay t h to ra da n nhng thnh phn c cung cp sn.

1.4.1.3. ng dng in hnh trn Windows

1.4.1.4. Cc kiu tp tn xy dng mt ng dng trn Windows

Chng trnh ngun

Tng t nh cc chng trnh c chun, bao gm cc tp tin tiu (header) cha trong tp tn *.h, *.hpp. Cn m ngun (source code) cha trong tp tin *.c hay *.cpp.

Tp tin nh ngha

Tp tn ny c phn m rng l *.def, dng nh ngha cc iu khin do chng trnh to ra khi vit ng dng to DLL, ngoi ra cn dng khai bo vng nh heap khi chy chng trnh. Lc trc do vn tng thch vi Windows 3.1 nn tp tin ny thng c dng, cn ngy nay chng t c dng n.

Cc file cha ti nguyn ca ng dng

Cc file *.ico l cc biu tng (icon) c dng trong chng trnh. Thng thng cc cng c lp nh n Windows u c cc tool to cc nh ny.

Con tr chut ca ng dng c th c v li di dng cc biu tng v lu n a vi dng file *.cur.

Cc file dng nh bitmap dng minh ha c lu dng file *.bmp. Tp tn ti nguyn *.rc l phn khai bo cc ti nguyn nh thc n, hp

thoi, v cc nh danh ch n cc tp tn dng *.ico, *.cur, *.bmp,...

1.4.1.5. Cc kiu d liu mi

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Cc kiu d liu trn Windows thng c nh ngha nh ton t typedef trong tp tin windows.h hay cc tp tin khc. Thng thng cc tp tin nh ngha ny do Microsoft vit ra hoc cc cng ty vit trnh bin dch c to ra, nht thit n phi tng thch vi h iu hnh Windows 98, hay NT da n kin trc 32-bit.

Mt vi kiu d liu mi c tn vit tt rt d hiu nh UINT l mt d liu thng c dng m n gin l kiu unsigned int, trong Windows 9x kiu ny c kch thc l 32- bit. i vi kiu chui th c kiu PSTR kiu ny l mt con tr n mt chui tng t nh char*.

Tuy nhin, cng c mt s kiu c khi bo tn thiu r rng nh WPARAM v LPARAM. Tn ny c t v c ngun ngc lch s su xa. Khi cn h iu hnh Windows 16-bit th tham s th 3 ca hm WndProc c khai bo l kiu WORD, vi kch thc 16- b it, cn tham s th 4 c kiu LONG l 32-bit. y l l do ngi ta thm tin t "W", "L" vo t "PARAM". Tuy nhin, ong phin bn Windows 32-bit, th WPARAM c nh ngha nh l UINT v LPARAM th c nh ngha nh mt kiu LONG, do c hai tham s ny u c gi l 32-bit. iu ny l mt s nhm ln v WORD vn l gi tr 16-bit trong Window 98.

Trong th tc x l ca s WndProc gi tr tr v l kiu LRESULT. Kiu ny n gin c nh ngha nh l kiu LONG.

Ngoi ra, c mt kiu thng xuyn dng l kiu HANDLE l mt s nguyn 32-bit c s dng nh mt kiu nh danh. C nhiu kiu nh danh nhuhg nht thit tt c phi c cng kch thc vi HANDLE.

Bng sau m t mt s kiu d liu mi:

Kiu ngha

BYTE

HANDLE

HWND

S nguyn 32-bit, nh danh.

S nguyn 32-bit, nh danh.

Gi tr 8-bit khng du.

WORD

LONG

DWORD

UINT

S nguyn 16-bit khng du.

S nguyn 32-bit khng du.

S nguyn khng du 32-bit.

long 32-bit.

LPSTR

BOOL Bool.

Con tr chui.

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LP TRNH c TRN

LPCSTR Hng con tr chui.

WPARAM 32-bit.

LPARAM 32-bit.

BSTR Gi tr 32-bit tr n k t.

LPVOID Con 32-bit n mt kiu khng xc nh.

LPTSTR Ging nh LPSTR nhng c th chuyn sang dng Unicode v DBCS.

LPCTSTR Ging nh LPCTSTR nhng c th chuyn sang dng Unicodc v DBCS.

Bng 1.1 M t cc kiu d liu mi

1.4.2. Khun m u chung to m t ng dng

Mt ng dng n gin nht ca Windows bao gm c hai hm l WinMain v x l ca s WinProc. Do hai hm ny l quan trng v khng th thiu trong cc ng dng Windows.

Hm WinMain thc hin cc chc nng sau :

nh ngha lp ca s ng dng. ng k lp ca s va nh ngha. To ra th hin ca s ca lp cho. Hin th ca s. Khi ng chu nh x l thng ip.

Hm x l WinProc c chc nng x l tt c cc thng ip c lin quan n ca s.

1.4.3. Hm WinMain

Hm chnh ca mt ng dng chy trn Windows l hm WinMain, c khai bo nh sau:

int WINAPI WinMain(HINSTANCE hlnstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow);

Chng ta s tm hiu mt hm WinMain mu sau y.

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int WINAPI WinMain(HINSTANCE hlnstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)

{

static TCHAR szAppName[] = TEXT("HelloWin"); // tn ng dng

HWND hwnd;

MSG msg;

WNDCLASS wndclass; // bin nh ngha mt ca s

/* nh ngha kiu ca s */

wndclass.style = SC_HREDRAW I CS_VREDRAW;

wndclass.lpfnWndProc = WndProc; //Hm th tc ca s

wndclass.cbClsExtra = 0;

wndclass.cbWndExa = 0;

wndclass.hlnstance = hlnstance; //nh danh ng dng

wndclass.hlcon = Loadlcon (NULL, IDI_APPLICATION);

wndclass.hCursor = LoadCusor (NULL, IDC_ARROW);

wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);

wndclass.lpszMenuName = NULL; //Khng c menu

wndclass.lpszClassName = szAppName; // tn ng dng

/* ng k lp ca s */

if (!RegisterClass(&wndclass)) return 0;

/* To lp ca s */

hwnd = Create Window (szAppName, // Tn ca s

"Hello Program", // Tiu

WS_OVERLAPPEDWINDOW, //K iu ca s

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CW_USEDEFAULT, // Ta X

CW_USEDEFAULT, // Ta y

CW_USEDEFAULT, //Chiu rng

CW_USEDEFAULT, //Chiu di

NULL, //Ca S cha

NULL, //Khng c menu

hlnstacne, //nh danh ng dng

NULL); // Tham s b sung

/* Hin th ca s */

ShowWindow (hwnd, iCmdShow);

UpdateWindow (hwnd);

/* Chu trnh x l cc thng ip*/

while (GetMessage (&msg, NULL, 0, 0))

{

TranslateMessage (&msg);

DispatchMessage (&msg);

}

return msg.wParam;

}

nh ngha mt lp ca s :

u tin ca vic xy dng mt ng dng Windows l phi nh ngha mt lp ca s cho ng dng. Windows cung cp mt cu trc WNDCLASS gi l lp ca s, lp ny cha nhng thuc tnh to thnh mt ca s.

typedef struct _WNDCLASS

{

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UINT style;

WNDPROC lpfnWndProc;

int cbClsExtra;

HINSTANCE hlnstance;

HICON hlcon;

HCURSOR hCursor;

HBRUSH hbrBackground;

LPCSTR IpszMenuName;

LPCSTR IpszClassName;

} WNDCLASS, *PWNDCLASS;

ngha thuc tnh ca cu trc WNDCLASS c m t trong bng sau :

Thuc tnh ngha ghi ch

style Kiu lp Kt hp nhiu kiu gi tr khc nhau bng ton t OR.

ipfnWndProc Con tr n th tc window

cbClsExa S byte c cp pht thm sau cu trc window-class

Mc nh

cbWndExtra S byte c cp pht thm sau mt instance ca window

Mc nh

hlnstance nh danh cha th tc ca s ca lp window

hlcon nh danh ca biu tng Dng hm Loadlcon

hCursor nh danh ca con tr chut Dng hm LoadCursor

hbrBackground nh danh ca chi t nn Dng hm GetStockObject

IpszMenuName Tn thc n Tn thc n gn vi ca s, thc dn ny c khai bo trong tp tin

ti nguyn.

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LP TRNH c TRN

IpszClassName Tn lp

Bng 1.2 M t thuc tnh ca lp ca s

ng k lp ca s :

Sau khi nh ngha mt lp ca s, phi ng k lp ca s bng hm Register Class :

ATOM RegisterClass( CONST WNDCLASS * lpWndClass );

To ca s :

.p ca s nh ngha nhng r tnh rhnng ca ra s, rhn php to ra nhiu ra s da trn mt lp. Khi to ra mt ca s ca hm CreateWindow, ta ch nh cc c tnh ring ca ca s ny, v phn bit n vi cc ca s khc to ra cng mt lp.

Khai bo hm to ca s :

HWND CreateWindow(

LPCSTR lpClassName, // Tn lp ca s ng k

LPCSTR lpwindowName, //Tn ca ca s

DWORD dwStyle, //K iu ca ca s

int X, / / V tr ngang ban u

int y, // V tr dc ban u

int nWidth, // rng ban u

int nHeight, // cao ban u

HWND hVVndParent, //nh danh ca ca s cha

MENU hMenu, //nh dang ca thc n

INSTANCE hlnstance, // nh danh th hin ng dng

PVOID lpParam // Cc tham s ban u

);

Hin th ca s :

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Sau khi gi hm CreateWindow, mt ca s c to ra bn trong Windows, iu ny c ngha l Windows cp pht mt vng nh lu gi tt c cc thng tin v ca s c ch nh trong hm CreateWindow. Nhng thng s ny s c Windows tm li khi cn thit da vo nh danh m hm to ca s tr v. Tuy nhin, lc ny ca s cha xut hin trn mn hnh Windows, xut hin cn phi gi hm ShowWindow.

Hm ShowWindow c khai bo nh sau:

BOOL ShowWindow(

HWND hWnd, //nh danh ca ca s cn th hin

int nCmdShow // Trng thi hin th

);

Mt s trng thi ca tham s nCmdShow:

SW_HIDE : n ca s. SW_MAXIMIZE : Phng ca s ra ton b mn hnh. SW_MINIMIZE : thu nh thnh biu tng trn mn hnh. SW_RESTORE : Hin th di dng chun.

1.4.4. Hm x l ca s WndProc

Mt chng trnh Windows c th cha nhiu hn mt hm x l ca s. Mt hm x l ca s lun kt hp vi mt lp ca s c th. Hm x l ca s thng c t tn VVndProc.

Hm WndProc c chc nng giao tip vi bn ngoi, tc l vi Windows, ton b cc thng ip gi n ca s iu c x l qua hm ny.

Hm ny thng c khai bo nh sau :

LRESULT CALLBACK WndProc ( HWND, UINT, WPARAM, LP ARAM );

Trong tham s u tin l nh danh ca ca s, tham s th 2 l nh danh thng ip, v cui cng l 2 tham s WPARAM v LPARAM b sung thng tin km theo thng ip.

Chng ta s tm hiu mt hm x l ca s WndProc sau:

LRESULT CALLBACK WndProc (HWND hwnd, UINT msg, WPARAM wParam, LPARAM IParam)

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{

HDC hdc;

PAINTSTRUCT ps;

RECT rect;

/*x l cc thng ip cn thit vi ng dng*/

switch (msg)

{

case WM_CREATE:

/*Vit on m khi to ca s*/

return 0;

case WM_PAINT:

/*Vit on m khi t v li ca s*/

hdc = BeginPaint ( hwnd, &ps);

GetClientRect (hwnd, &rect);

DrawText(hdc, "Hello", -1, &rect,

DT_SINGLELINE| DT_CENTER| DT_VCENTER);

EndPaint ( hwnd, &ps);

return 0;

case WM_SIZE:

/*Vit on m khi kch thc ca s thay i*/

return 0;

case WMJDESTROY:

/*ca s b ng*/

PostQuitMessage (0);

return 0;

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LP TRNH c TRN


}

LP TRNH c TRN

return DefWindowProc ( hwnd, msg, wParam, IParam);

}

Thng thng chng ta ch chn x l cc thng ip cn thit c lin quan n chc nng ca ng dng. Cc thng ip khc th giao cho hm x l mc nh lm vic (hm DefWindowProc).

1.4.5. x l thng ip

Sau khi ca s c hin th trn mn hnh, th chng trnh phi c cc thng n nhp ca ngi dng t bn phm hay thit b chut. Windows s duy tr mt hng i thng ip cho mi chng trnh chy trn n. Khi mt s kin nhp thng tn xut hin, Windows s dch s kin ny thnh dng thng ip v a n vo hng i thng ip ca ng dng tng ng.

Mt ng dng nhn cc thng ip t hng i thng ip bng cch thc thi mt on m sau:

while ( GetMessage(&msg, NULL, 0 ,0))

{



}

Trong msg l mt bin cu trc kiu MSG c nh ngha trong tp tin tiu WINUSER.H.

typedef struct tagMSG

{

HWND hwnd;

UINT message;

WPARAM wParam;

LPARAM IParam;

DWORD me;

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POINT pt;

LP TRNH c TRN

} MSG, *PMSG;

Kiu d liu POINT i mt kiu cu trc khc, c nh ngha trong tp tin tiu WINDEF.H, v c m t :

typedef struct tagPOINT

{

LONG x;

LONG y;

} POINT, *PPOINT;

ngha ca cc trng trong cu trc MSG

S hwnd : nh danh ca ca s m thng ip pht sinh.S message : nh danh ca thng ip, v d nh thng ip pht sinh khi bm

nt chut tri l WMJLBUTTONDOWN c gi tr 0x0201.'S wParam : Tham s 32-bit cha cc thng tin ph thuc vo tng thng ip c

th.s lParam : Tham s 32-bit ph thuc vo thng ip.s time : Thi gian t thng ip trong hng i.s pt : Ta ca chut khi t thng ip vo hng i

Hm GetMessage s tr v 0 nu msg cha thng ip c nh danh WM_QUIT (0x0012), khi vng lp thng ip nghg v ng dng kt thc. Ngc li th hm s tr v mt gi tr khc 0 vi cc thng ip khc.

1.4.6. Xy dng m t ng dng u tin

Mt ng dng thng c giao din nn tng l mt khung ca s, to c ca s ny chng ta thc hin bng cch khai bo mt lp ca s v ng k lp ca s . ca s tng tc c th chng ta phi vit hm x l ca s WndProc khi tt c cc thng ip lin quan n ca s s c truyn vo cho hm ny. on chng trnh sau l khung sn cho cc chng trnh vit trn Windows, bao gm 2 hm chnh l :

WinMain : hm chnh ca chng trnh thc hin cc chc nng :

Khai bo lp ca s. ng k lp ca s va khai bo. To v hin th lp ca s trn. Vng lp nhn thng ip.

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WndProc : Hm x l thng ip gi n ca s.

/* HELLO WORLD.c */

#include

LRESULT CALLBACK WndProc ( IIWND. UINT, WPARAM, LPARAM );

int WINAPI WinMain (HINSTANCE hlnstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)

{

static TCHAR szAppName [] = TEXT ("HelloWorld");

HWND hwnd;

MSG msg;

WNDCLASS wndclass;

wndclass.style = CS_HREDRAW|CS_VREDRAW;

wndclass.lpfnWndProc = WndProc;

wndclass.cbClsExtta = 0;

wndclass.cbWndExtra = 0;

wndclass.hlnstance = hlnstance;

wndclass.hlcon = Loadicon ( NULL, IDI_APPLICATION );

wndclass.hCursor = LoadCursor ( NULL, IDC_ARROW );

wndclass.hbrBackground =

( HBRUSH ) GetStockObject ( WHITE_BRUSH );

wndclass.lpszMenuName = NULL;

wndclass.lpszClassName = szAppName;

if ( RegisterClass ( &wndclass))

{

MessageBox(NULL, TEXT (" The program requires Windows"), szAppName,MB JCONERROR);

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return 0;

}

hwnd = CreateWindow ( szAppName, // Tn lp ca s

TEXT (" The Hello World Program"), // Tiu ca s

WS_OVERLAPPEDWINDOW, //Kiu ca s

CWJJSEDEFAULT, // Ta X

CWJJSEDEFAULT, // Ta y

CWJJSEDEFAULT, // Chiu ngang

CWJJSEDEFAULT, // Chiu dc

NULL, // ca s cha

NULL, //Thc n

hlnstance, //nh danh

NULL ); // Tham s

ShowWindow ( hwnd, iCmdShow);

UpdateWindow ( hwnd);

while ( GetMessage ( &msg, NULL, 0, 0))

{


DispatchMessage (& m sg);

}

return msg.wParam;

} //End WinMain

LRESULT CALLBACK WndProc (HWND hwnd, UINT msg, WPARAM wParam, LPARAM IParam)

{

HDC hdc;

Trang 21


PAINTSTRU CT ps;

RECT rect;

switch ( msg)

{

case WM_CREATE:

return 0;

case WM_PAINT:

hdc = BeginPaint ( hwnd, &ps);

GetClientRect ( hwnd, &rect);

DrawText( hdc, TEXTfHello World"), -1, &rect,

DT_SINGLELINE I DT_CENTER I DT_VCENTER );

EndPaint ( hwnd, &ps);

return 0;

case WMJDESTROY:


return 0;

} //End switch

return DefWindowProc ( hwnd, msg, wParam, IParam);

}

Bng di y lit k ngha ca cc hm c s dng trong 2 hm WinMain v WndProc ca chng trnh HELLOWORLD.C.

Tn hm ngha

Loadlcon Np mt biu tng s dng trong chngtrnh.

LoadCursor Nap mt con tr chut cho chng trnh.

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LP TRNH c TRN

GetStockObject Nhn mt i tng ha, trong trng hp ca chng trnh th ly mt chi t d t li nn ca ca s.

RegisterClass ng k mt lp ca s cho ca s ng dng trong chng trnh.

MessageBox Hin th mt thng ip.

CreateWindow To mt ca s da trn mt lp ca s.

ShowWindow Hin th ca s ln mn hnh.

UpdateWindow Yu cu ca s v li chnh bn thn n.

GetM esssage Nhn mt thng ip t hng i thng ip.

T ranslateMessage Dch thng ip bn phm.

DispatchMessage Gi thng ip n hm x l ca s.

BegnPaint Khi to chc nng v ca ca s.

GetCIientRect Ly hnh ch nht lu vng lm vic.

DrawText Hin th mt chui vn bn.

EndPaint Kt thc vic v ca s.

PostQuitMessage a thng ip thot vo hng i thng ip.

DefWindowProc Thc hin vic x l mc nh cc thng ip.

Bng 1.3 M t cc hm c s dng ong chng trnh minh ha

1.4.7. M t s qui c t tn b in

Khi vit mt chng trnh tig dng ln vi nhiu kiu khai bo bin khc nhau, nu vic khai bo cc tn bin khng thch hp s lm cho chng trnh phc tp thm, i khi lm kh ngay c ngi vit ra cc m ngun . V vy cc lp trnh vin thng qui c sao cho mt tn bin va gi c chc nng ca n va xc nh c kiu loi. C rl nhiu phong cch t tn, trong s th c phong cch t tn theo c php Hungary (Hungarian Notation) l c dng nhiu nht. Qui c rt n gin l bt u tn bin th vit ch thng v cc ch u th hin kiu d liu ca bin, v c gi l cc tin t. V d nh bin szCmdLine l mt bin lu chui nhp t dng lnh, sz l th hin cho bin kiu chui kt thc k t 0, ngoi ra ta hay thy hlnstance v hPrevInstance, trong h vit tt cho kiu handle, kiu d liu nguyn thng c khai bo dng tin t l ch i.

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C php Hungary ny gip cho ngi lp trnh rt nhiu trong khu kim a li ca chng trnh, v khi nhn vo hai bin ta c th d dng nhn bit c s khng tng thch gia hai kiu d liu th hin trong tn ca hai bin.

Bng m t mt s tin t khi t tn bin ca cc kiu d liu :

Tin t Kiu d liu

c char, WCHAR, TCHAR

by BYTE

n short

illt

bin lu ta X, y

b BOOL

w WORD

1 long

dw DWORD

s string

sz chui kt thc bi k t 0

h handle

p pointer

Lpsz con tr di chui k t kt thc k t 0

Bng 1.4 M t kiu t tn bin

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LP TRNH c TRN

Chng 2

HP THOI V THANH TRNH N 2.1. M U

Hp thoi (dialog) v thanh nh n (menu) l cc thnh phn khng th thiu trong vic t chc giao tip gia ngi s dng v chng trnh. Hp thoi c xem nh l mt loi ca s c bit, l cng c mm do, linh hot a thng tn vo chng trnh mt cch d dng. Trong khi menu l cng c gip ngi dng thc hin cc thao tc n gin hn, thng qua cc nhm chc nng thng s dng.

2.2. HP THOI

Hp thoi phi hp gia ngi s dng vi chng trnh bng mt s phn t iu khin m cc phn t ny nhn nhim v thu nhn thng tin t ngi dng v cung cp thng tn n ngi dng khi ngi dng tc ng n cc phn t iu khin. Cc phn t iu khin ny nhn ca s cha l mt hp thoi. Cc phn t iu khin thng l cc Button, List Box, Combo Box, Check Box, Radio Button, Edit Box, Scroll Bar, Static.

Tng t nh cc thng ip gi n th tc WndProc ca ca s chnh.Windows s gi cc thng ip x l hp thoi n th tc x l hp thoi DlgProc. Hai th tc VVndProc v th tc DlgProc tuy cch lm vic ging nhau nhng gia chng c nhng im khc bit cn lu . Bn trong th tc x l hp thoi bn cn khi to cc phn t iu khin bn trong hp thoi bng thng ip WM_INITDIALOG, cui cng l ng hp thoi,

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NGN NG LP TRNH LP TRNH c TRNWINDOWScn th tc x l WndProc th khng c. C ba loi hp thoi c bn. Hp thoi trng thi (modal), hp thoi khng trng thi (modeless) v hp thoi thng dng (common dialog) m chng ta s cp c th trong cc phn di.

2.2.1. H p thoi trn g thi

Hp thoi trng thi (modal) l loi hp thoi thng dng trong cc ng dng ca chng ta. Khi hp thoi trng thi c hin th th bn khng th chuyn iu khin n cc ca s khc, iu ny c ngha bn phi ng hp thoi hin hnh trc khi mun chuyn iu khin n cc ca s khc.

2.2.1.1. Cch to hp thoi n gin

Sau y l chng trnh to ra mt hp thoi n gin. Hp thoi c to ra c ni dung nh sau.

Khi hp thoi hin ln c xut hin dng ch "HELLO WORLD", bn trn hp thoi c mt biu tng ca hp thoi l mt icon, v pha di hp thoi l mt nt bm (Button) c tn l OK, khi nhp chut vo nt OK th hp thoi "HELLO WORLD" c ng li.

. D idlo j3_l - J D J x jDialog

HELLO WORLD

OK

Hnh 2.1 Hp thoi n gin

on code chng trnh nh sau (V d 2.1):

DIALOG.CPP (trch dn)

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);

BOOL CALLBACK DialogProc (HWND, UINT, WPARAM, LPARAM);

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAMlParam)

{

static HINSTANCE hlnstance;

Trang 26


switch (message)

{

case WM_CREATE:

hlnstance = ((LPCREATESTRUCT) lParam)->hInstance ;

return 0 ;

case WM_COMMAND :

switch (LOWORD (wParam))

{

case IDC_SHOW:

DialogBox (Mnstance, TEXT ("DIALOG1"),

hwnd, DialogProc);

break;

>

return 0 ;

case WM_DESTROY:


return 0 ;

}

return DefWindowProc (hwnd, message, wParam, IParam);

}

/*-------------------hm x l thng ip hp thoi---------------------------*/

BOOL CALLBACK DialogProc (HWND hDlg, UINT message, WPARAM wParam, LPARAM IParam)

{

switch (message)

{

case WM_INli DIALOG:

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return TRUE;

case WM_COMMAND :


{

case IDOK:

EndDialog (hDlg, 0 );

return TRUE;

}

break;

}

return FALSE;

>

DIALOG1.RC (trch dn)

/* -----------------------------------------------------------dialog------------------------------------

DIALOG1 DIALOG DISCARDABLE 40, 20, 164, 89

STYLE DS_MODALFRAME I WS_POPUP

FONT 9, "MS Sans Serif"

BEGIN

DEFPUSHBUTTON "OK",IDOK,54,65,50,14

CTEXT "HELLO WORLD ",IDC_STATTC,53,38,72,10

ICON IDI_ICON1,IDC_STATIC,68,9,20,20

END

MENU1 MENU DISCARDABLE

BEGIN

POPUP "Dialogl"

Trang 28

LP TRNH c TRN


BEGIN

LP TRNH c TRN

MENUITEM "&Show", IDC_SHOW

END

END

2.2.I.2. Hp thoi v to mu template cho hp thoi

Trong v d 2.1 trn, ta to hp thoi bng cch dng cc cu lnh cha trong file ti nguyn DIALOG1.RC. Cch lm ny gip ta hiu cu trc lnh ca Windows, tuy nhin cng c Visual C++ Developer Studio, ta c th thit lp mt hp thoi trc quan hn nh sau : Chn Insert t thc n Resource View thm mt hp thoi, mn hnh c th hin nh trong hnh 2.2.

Miscrosoft s hin th hp thoi trc quan cng vi thanh cng c bn c th thm cc thnh phn iu khin vo hp thoi. Chng ta c th iu chnh cc thuc tnh ca hp thoi nh tn hp thoi, ID hp thoi, v tr hin th ca hp thoi trn ca s chnh, kch thc ch v kiu ch th hin trn hp thoi..,w bng cch nhn chut phi trn hp thoi th ca s Properties ca hp thoi c hin th (hnh 2.3).

B -rg R esource Irtc ludes...

[+ ,D= R esource Sym bols...

g S a v e v id u l_ l .r c

g Checkout...I

Im port..

* Docking View

Hide

ofj* P roperties

3 ClassView ) m R esource ... =1 FileView~[

Hnh 2.2 Thm mt Dialog trong Resource View

*JDialog Properties-W Geneial I Styles I More Styles I Extended Styles I k I I

I Caption:

Menu:

ID: fi M m i r i U i Caption: I

Font name: MS Sans Serif I------------------Menu:

Font size: 9

Font... I X Pos: 4 YPos: p ic P Class name: I

HQnh 2.3 Hp thoi Properties ca Dialog

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Trong ca s Properties ny chn tab Styles, b mc chn Title Bar v khng cn to tiu cho ca s. Sau ng ca s Properties ca hp thoi li.

By gi bt u thit k din mo cho hp thoi. Xa nt Cancel v khng cn n nt ny. thm mt biu tng vo hp thoi ta nhn nt Picture ln thanh cng c v kch chut vo hp thoi ri ko khung ch nht theo kch thc mong mun. y l ni m biu tng c hin th. Nhn chut phi vo khung ch nht va to, chn Properties t tnh n xut hin v nguyn nh danh ca biu tng l IDC_STATIC. nh danh ny s c Windowns t khai bo trong file Resource.h vi gi tr -1. Gi tr -1 l gi tr ca tt c cc nh danh m chng trnh khng cn tham chiu n. Tip n l chn i tng Icon trong trong mc Type, ri g nh danh ca Icon cn thm vo trong mc Image. Nu to ra biu tng Icon c th ch vic chn Icon t danh sch cc Icon trong mc Image.

thm dng ch "HELLO WORLD" vo hp thoi, chn Static Text t bng cng c v t i tng vo hp thoi. Nhn chut phi hin th Properties ca Static Text, sau vo mc caption nh dng ch "HELLO WORD" vo y.

Dch v chy chng trnh sau xem file DIALOG1.RC di dng text, ni dung hp thoi c Windows pht sinh nh sau :

DIALOG1 DIALOG DISCARDABLE 40, 20, 164, 90

STYLE DS_MODALFRAME I WS_POPUP

FONT 9, "MS Sans Serif"

BEGIN

DEFPUSHBUTTON "OK",IDOK,54,65,50,14

CTEXT "HELLO WORLD " ,IDC_STATIC,53,38,72,10

ICON IDI_ICON1,IDC_STATIC,68,9,21,20

END

Dng u tin l tn ca hp thoi "DIALOG1" k tip l t kha DIALOG, DISCARDABLE v tip sau l 4 s nguyn. Hai s nguyn u tin ch v tr dng, ct ca hp thoi s c hin th trn ca s chnh. Hai s nguyn tip theo xc nh kch thc ca hp thoi theo th t ct v dng.

Lu : Cc thng s nh ta v kch thc ca hp thoi khng tnh theo n v Pixel m tnh theo kch c ca Font ch. s o ca ta X v chiu rng da trn 1/4 n v rng trung bnh ca Font ch. s o ca ta y v chiu cao da trn 1/8 n v cao trung bnh ca Font ch.

Theo sau lnh STYLE l cc thuc tnh ca hp thoi m bn cn thm vo. Thng thng hp thoi modal s dng cc hng WSJPOPUP v DS_MODALFRAME ngoi ra

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NGN NG LP TRNH LP TRNH c TRNWINDOWScn c cc hng WS_CAPTION, WS_MAXIMIZEBOX, WS_MINIMIZEBOX,w s POPUP, WSJVSCROLL, ws HSCROLL, WS_SYSMENU..... Lnh BEGIN v lnhEND c th c thay bng { v }. Trong vi d trn, hp thoi s dng 3 kiu iu khin l DEFPUSHBUTTON (kiu nt bm mc nh), ICON (biu tng), v kiu CTEXT (vn bn c canh gia). Mt kiu iu khin c khai bo tng qut nh sau.

Control-type "text", id , xPos, yPos, xWidth, yHeight, iStyle.

Control-type l cc t kha khai bo kiu iu khin nh DEFPUSHBUTTON, ICON, CTEXT, .... id l nh danh ca cc iu khin, thng thng mt iu khin c mt nh danh ring c gi cng vi thng ip WM_COMMAND n cc th tc x l thng ip ca ca s cha. xPos, yPos l v tr ct, dng him th ca iu khin trn ca s cha. xWidth, yHeight l chiu rng v chiu cao ca iu khin . i s cui cng l iStyle, i s ny ty chn dng nh ngha thm cc kiu ca s m iu khin cn th hin chng thng l cc hng w s_ c khai bo trong tp tin .h" ca Windows.

2.2.1.3. Th tc x l thng ip ca hp thoi

Th tc x l thng ip ca hp thoi dng x l tt c cc thng ip t b qun l hp thoi ca Windows gi n hp thoi. Th tc ny c Windows gi khi c s tc ng ln cc phn t iu khin nm trong hp thoi.

Xt th tc x l hp thoi DialogProc trong v d 2.1. Th tc ny c 4 tham s nh th tc WndProc, v th tc ny c nh ngha kiu tr v l CALLBACK.Tuy hai th tc ny tng t ging nhau nhng thc s gia chng c mt vi s khc bit ng ch .

Th tc DialogProc tr v gi tr kiu BOOL, trong khi th tc WindProc th tr v gi tr LRESULT.

Th tc DialogProc tr v gi tr TRUE (gi tr khc 0) nu n x l thng ip v ngc li nu khng x l cc thng ip th thu tc tr v gi th l FALSE (tr 0). Cn th tc WindProc th gi hm DefWindowProc vi cc thng ip khng cn x l.

Th tc DialogProc khng cn x l thng ip WM_DESTROY, cng khng cn x l thng ip WM_PAINT v cng khng nhn c thng ip WM_CREATE m l thng ip W MJNITDIALOG dng e khi to hp thoi.

Ngoi x l thng ip WM_INITDIALOG, th tc x l thng ip hp thoi ch x l mt thng ip duy nht khc l WM_COMMAND. y cng l thng ip c gi n ca s cha khi ta kch hot (nt nhn ang nhn c focus) ln cc thnh phn iu khin. Ch danh ID ca nt OK" l IDOK s c cha trong word thp ca i s wParam. Khi nt ny c nhn, th tc DialogProc gi hm EndDialog kt thc x l v ng hp thoi.

Cc thng ip gi n hp thoi khng i qua hng i m n c Windows gi c tip hm DialogProc truyn cc thng ip vo cho th tc x l hp thoi.V vy, khng phi bn tm v hiu ng ca cc phn tt c quy nh trong chng trnh chnh.

2.2.1.4. Gi hin th hp thoi v cc vn lin quan

Trang 31


Trong th tc WndProc khi x l thng ip WM_CREATE Windows ly v nh danh hlnstance ca chng trnh v lui n trong bin nh hlnstance nh sau.

hlnstance = ((LPCREATESTRUCT) lParam)->hInstance;

Diaogl kim tra thng ip WM_COMMAND xem word thp ca i s wParam c bng gi tr IDC_SHOW (ch danh ca thnh phn Show trong thc n). Nu phi, tc chn mc Show n trnh n ca ca s chnh v yu cu hin th hp thoi, lc ny chng trnh gi hin th hp thoi bng cch gi hm.

DialogBox (hlnstance, TEXT ("DIALOG1"), hwnd, DialogProc)

i s u tin ca hm ny phi l hlnstance ca chng trnh gi, i s th hai l tn ca hp thoi cn hin th, i s th 3 l ca s cha m hp thoi thuc v, cui cng l a rh ra th rr x l cc thng ip ra hp thoi.

Chng trnh khng th tr iu khin v hm WndProc cho n khi hp thoi c ng li. Gi tr tr v ca hm DialogBox l gi tr ca i s th hai trong hm EndDialog nm bn trong th tc x l thng ip hp thoi. Tuy nhin chng ta cng c th gi thng ip n hm WndProc yu cu x l ngay c khi hp thoi ang m nh hm SendMessage nh sau :

SendMessage(GetParent(hDlg), message, wParam, lParam)

Tuy Visual c++ Developer cung cp cho chng ta b son tho hp thoi c quan m ta khng cn phi quan tm n ni dung trong tp tin .RC. Tuy nhin vi cch thit k mt hp thoi bng cc cu lnh gip chng ta hiu chi tit hn cu trc lnh ca Windows hn th na tp lnh dng thit k hp thoi phong ph v a dng hn rt nhiu so vi nhng g m ta trc quan c trn b son tho ca Developer. Bng cch s dng cc lnh c bit trong tp tin Resource editor ca Visual c++ ta c th to ra nhiu i tng m trong b son tho khng c.

Thm hng WS_THINKFRAME vo mc STYLE co gin hp thoi (tng ng vi trong boder ta chn mc Resizing).

t ni dung tiu cho hp thoi ta ch vic thm hng WS_CAPTION trong STYLE.

STYLE DS_MODALFRAME I WS_POPUP I WS_CAPTION

CAPTION "Hello Dialogl"

C th dng cch khc thm tiu cho hp thoi, bng cch trong khi x l thng ip WM_INITDIALOG thm vo dng lnh:

SetWindowText(hDlg,TEXT("Hello Dialog"));

Trang 32


Khi hp thoi c tiu ri, c th thm cc chc nng phng to v thu nh hp thoi bng hng ws_ MINIMIZEBOX, w s MAXIMIZEBOX.

C th thm trnh n vo hp thoi nu mun bng on lnh.

DIALOGl DIALOG DISCARDABLE 40, 20,164, 90

STYLE DS_MODALFRAME I WS_POPUP I WS_CAPTION

CAPTION "Hello Dialogl"

MENU MENU1

Trong MENU1 l tn ca trnh n ta to. Trong Visual C++ Developer ta ch cn chn tn thc n trong mc Menu nh hnh sau.

*11? General I Styles I More Styles I Extended Styles I h I I

ID: |"D IA L0G 1" I Caption: I hung dau

Font name: MS Sans Serif . . 1= ----------------------------- 1Menu: B n a m H

Font size: 9

Font... I


LP TRNH c TRN

LTEXT Static SS_LEFT 1 WS_GROUP

CTEXT Static SS_CENTER 1 WS_GROUP

RTEXT Static SS_RIGHT 1 WS_GROUP

ICON Static SSJCON

EDITTEXT Edit ES_LEFT 1 WSJBORDER 1 WS_STABSTOP

SCROLLBAR Scrollbar SBS_HORZ

LISTBOX Listbox LBS_NOTIFY 1 WS_BORDER 1 WS_VSCROLL

COMBOBOX Combobox CBS_SIMPLE 1 WS_TABSTOP

Bng 2.1 Cc kiu iu khin

Cc kiu iu khin c khai bo trong resource script c dng nh sau, ngoi kiu iu khin LISTBOX, COMBOBOX, SCROLLBAR, EDITTEXT.

Control-type "text", id, xPos, yPos, xVVidth, yHeight, iStyle

Cc kiu iu khin LISTBX, COMBOBOX, SCROLLBAR, EDITTEXT c khai bo trong resource script vi cu trc nh trn nhng khng c trng "text".

Thm thuc tnh cho cc kiu iu khin bng cch thay i tham s iStyle. V d ta mun to radio button vi chui din t nm bn tri ca nt th ta gn trng iStyle bng BS_LEFTTEXT c th nh sau.

RADIOBUTTON Radiol",IDC_RADIOl,106,10,53,15,BS_LEFTTEXT

Trong resource script ta cng c th to mt kiu iu khin bng lnh tng qut sau.

CONTROL "text", id, "class", iStyle, xPos, yPos, xWidth, yHeight

Trong class l tn lp mun to v d thay v to mt rado button bng cu lnh.

RADIOBUTTON "Radiol",IDC_RADI01,106,10,53,15,BS_LEFTTEXT

Thay bng on inh sau:

CONTROL"Radiol",IDC_RADI01,"button",106,10,53,15,BS_LEFTTEXT

2.2.1.5. V d chng trnh v hp thoi.

Trang 34


minh ha cho vic trao i thng ip gia cc thnh phn iu khin bn trong hp thoi (ng vai l mt ca s cha) vi cc thnh phn iu khin con nm bn trong hp thoi, v c ch qun l hp thoi ca Windows. Chng ta tin hnh xem xt v d 2-2. Kt qu thc hin ca chng trnh nh trong hnh 2.5.

ca s hp thoi gm c ba nhm nt chn radio.Nhm th nht dng chn i tng v l hnh ch nht hay hnh ellipse, nhm th hai dng chn mu t cho hnh v, nhm th 3 dng chn kiu t cho hnh v. Khi thay i vic chn mu t, kiu t th mu t v kiu t ca hnh v cnh bn s thay i theo mu t, v kiu t va mi chn. Khi nhn nt OK th hp thoi ng li v mu t, kiu t cng hnh v va mi v s c hin th ln ca s chnh. Nu nhn nt Cancel hoc nhn phm Esc th hp thoi c ng li nhng hnh v, mu t v kiu t khng c hin th ln ca s chnh. Trong v d ny nt OK v nt Cancel c ch danh ID ln lt l IDOK v IDCANCEL.Thng thng t ch danh cho cc phn t iu khin nm ong hp thoi c bt u bng ch ID. Biu tng chic xe p trn hp thoi l mt icon. Trn thanh tiu ca ca s chnh c mt biu tng, biu tng cng l mt icon ( l mt ly tr). Khi t cc nt radio vo hp thoi bng cng c Developer studio nh phi t cc nt theo th t nh hnh 2-5. Th khi Windows mi pht sinh m cho cc nt theo th t tng dn, iu ny gip chng ta d dng kim sot cc thao tc trn tp cc nt radio. Bn nh b lun mc chn Auto trong phn thit lp Properties ca cc nt chn radio. Bi v cc nt radio mang thuc tnh Auto yu cu vit t m lnh hn ngng chng thng kh hiu so vi cc nt khng c thuc tnh Auto. Chn thuc nh Group, Tab stop trong phn thit k Properties ca nt OK, nt Cancel, v hai nt radio u tin trong ba nhm radio c th chuyn focus (chn) bng phm Tab trn bn phm.

JOJ*]

BiushH5 _bL>IAbUN AL

r HS.CROSS

c H S _D IA G C R O S S

r HS_FDlAGONAL

r HS_HORIZONTAL

r HS_VERTICAL

OK

Hnh 2.5 Minh ha trao i thng ip qua cc iu khin

Chng trnh minh ha (V d 2.2):

DIALOG2.CPP (trch dn)

#include

#include "resource.h"

LRESULT CALLBACK VVndProc (HWND, UINT, WPARAM, LPARAM);

Trang 35


BOOL CALLBACK DialogProc (HWND, UINT, WPARAM, LPARAM);

in t iCurrentColor = IDC_BLACK, iCurrentFigure = IDC_RECT;

in t iCurrenBrush = IDC_HS_BDIAGONAL;

void PaintWindow(HWND hwnd, int iColor, int iFigure, int iBrush)

{

static COLORREF crColor[8] = { RGB(0, 0, 0), RGB(0, 0, 255), RGB(0, 255, 0), RGB(0, 255, 255), RGB(255, 0, 0), RGB(255, 0, 255), RGB(255, 255, 0), RGB(255, 255, 255)} ;

HBRUSH hBrash,hbrush;

HDC hdc ;

RECT rect;

hdc = GetDC (hwnd);

GetClientRect (hwnd, &rect);

if(iBrush==IDC_HS_BDIAGONAL)

hbrush=CreateHatchBrush(HS_BDIAGONAL,

crColor[iColor-IDC_BLACK]);

if(iBrush == IDC_HS_CROSS)

hbrush=CreateHatchBrush(HS_CROSS,

crColor[iColor - IDCJBLACK]);

if(iBrush == IDC_HS_DIAGCROSS)

hbrush=CreateHatchBrush(HS_DIAGCROSS,


if(iBrash == IDC_HS_FDIAGONAL)

hbrush=CreateHatchBrush(HS_FDIAGONAL,

crColor[iColor - IDCJ3LACK]);

if(iBrash == IDC_HS_HORIZONTAL)

hbrush=CreateHatchBrush(HS_HORIZONTAL,

Trang 36



if(iBrush == IDC_HS_VERTICAL)

hbrush=CreateHatchBrush(HS_BDIAGONAL,

crColor[iColor - IDC JBLACK]);

hBrush = (HBRUSH) SelectObject (hdc, hbrush);

if (iFigure == IDC_RECT)

Rectangle (hdc, rect.left, rect.top, rect.right, rect.bottom);

else

Ellipse(hdc, rect.left, rect.top, rect.right, rect.bottom);

DeleteObject (SelectObject (hdc, hBrush));

ReleaseDC (hwnd, h d c);

}

void PaintTheBlock(HWND hCl, int iColor, int iFigure, int iBrush)

{

InvalidateRect (hCtrl, NULL, TRUE);

UpdateW indow (hCtrl);

PaintWindow (hCtrl, iColor, iFigure,iBrush);

}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM IParam)

{

static HINSTANCE hlnstance;

PAINTSTRUCT p s;

switch (message)

{

case WM_CREATE:

Trang 37


hlnstance = ((LPCREATESTRUCT) lParam)->hInstance ;

return 0 ;

case WM_COMMAND:


{

case IDC_SHOW:

if (DialogBox (hlnstance, TEXT ("DIALOG"), hwnd, DialogProc))

InvalidateRect (hwnd, NULL, TRUE);

return 0 ;

}

break;

case WMJPAINT:

BeginPaint (hwnd, &ps);

EndPaint (hwnd, &ps);

PaintW indow (hwnd, iCurrentColor, iCurrentFigure, iCurrenBrush);

return 0 ;

case WM_DESTROY:

PostQuitMessage (0 ) ;

re tu rn 0 ;

}

re tu rn DefWindowProc (hwnd, message, wParam, IParam);

}

BOOL CALLBACK DialogProc (HWND hDlg, UINT message, WPARAM wParam, LPARAM IParam)

{

static HWND hCtrlBlock;

Trang 38


static in t iColor, iFigure,iBrush;

switch (message)

{

case W M JN ITD IALOG :

iColor = iCurrentColor ;

iFigure = iCurrentFigure ;

iBrush = iCurrenBrush;

CheckRadioButton(hDlg,IDC_BLACK,IDC_WHITE, iColor);

CheckRadioButton(hDlg,IDC_RECT,IDC_ELLIPSE,iFigure);CheckRadioButton (hDlg, IDC_HS_BDIAGONAL, IDC_HS_VERTICAL, iBrush);

hCtrlBlock = GetDlgltem (hDlg, IDC_PAINT) ;

SetFocus (GetDlgltem (hDlg, iColor)) ;

re tu rn FALSE ;

case WM_COMMAND:


{

case IDOK:

iCurrentColor = iColor ;

iCurrentFigure = iFigure ;

iCurrenBrush = iBrush;

EndDialog (liDlg, TRUE) ;

return TRUE ;

case IDCANCEL:

EndDialog (hDlg, FALSE) ;

return TRUE ;

case IDCJBLACK:

Trang 39


case IDC_RED:

case IDC_GREEN:

case IDC_YELLOW:

case IDC_BLUE:

case IDC_MAGENTA:

case IDC_CYAN:

case IDC_WHITE:

iColor = LOWORD (wParam);

CheckRadioButton (hDlg, ID C _B L A C K , IDCJWHITE, LOWORD (wParam));

PaintTheBlock (hCtrlBlock, iColor, Figure,iB rush);

return TRUE;

case IDC_RECT:

case IDC_ELLIPSE:

Figure = LOWORD (wParam);

CheckRadioButton (hDlg, IDCJRJECT, IDCJELLIPSE, LOW ORD (wParam));

PaintTheBlock (hCtrlBlock, iColor, iFigure,iBrash);

re tu rn TR U E;

case IDCJHSJBDIAGONAL:

case IDC_HS_CROSS:

case IDC_HS_DIAGCROSS:

case IDC_HS_FDIAGONAL:

case IDC_HS_HORIZONTAL:

case IDC_HS_VERTICAL:

iBrush = LOWORD (wParam)

CheckRadioButton(hDlg,IDC_HS_BDIAGONAL,IDC_HS_VERTICAL, LOWORD (wParam)) ;

Trang 40

WINDOWSPaintTheBlock (hCtrlBlock, iColor, iFigure,iBrush);

NGN NG LP TRNH LP TRNH c TRN

re tu rn TR U E;

}

break;

case WM_PAINT:

PaintTheBlock (hCtrlBlock, iColor, iFigure,iBrash);

break;

}

re tu rn FALSE ;

}

2.2.1.6. Lm vic vi cc thnh phn iu khin trong hp thoi

Cc thnh phn iu khin con u gi thng ip WM_COMMAND n ca s cha ca n v ca s cha c th thay i trng thi ca cc thnh phn iu khin con nh kch hot, nh du (check), b du check (uncheck) bng cch gi cc thng ip n cc thnh phn iu khin con nm trong n. Tuy nhin trong Windows cung cp c ch trao i thng ip gia cc thnh phn iu khin con vi ca s cha. Chng ta bt u tm hiu cc c ch trao i thng ip .

Trong v d 2.2 mu template ca hp thoi Dialog2 c th hin trong tp tin ti nguyn DIALOG2.RC gm c cc thnh phn. Thnh phn GROUPBOX c tiu do chng ta g vo, thnh phn ny ch n gin l mt khung vin bao quanh hai nhm nt chn radio, v hai nhm ny hon ton c lp vi nhau trong mi nhm.

Khi mt trong nhng nt radio c kch hot th ca s iu khin con gi thng ip WM_COMMAND n ca s cha ( y l hp thoi) vi word thp ca i s wParam cha thnh phn ID ca iu khin con, word cao ca i s wParam cho bit m thng bo. Sau cng l i s lParam mang handle ca ca s iu khin con. M thng bo ca nt chn radio lun lun l BN_CLICKED (mang gi tr 0). Windows s chuyn thng ip WM_COMMAND cng vi cc i s wParam v IParam n th tc x l thng ip ca hp thoi (DialogProc). Khi hp thoi nhn c thng ip WM_COMMAND cng vi cc i s lParam v wParam, hp thoi kim tra nng thi ca t t c cc thnh phn iu khin con nm trong n v thit lp cc trng thi cho cc thnh phn iu khin con ny.

C th nh du mt nt chn bng cch gi thng ip

S endM essage (hwndCtrl ,M B_SETCHECK, 1, 0);

Trang 41


V ngc li mun b chn mt nt no th dng hm.

SendMessage (hwndCtrl, MB_SETCHECK, 0, 0);

Trong i s hwndCtrl l handle ca ca s iu khin con.

Chng ta c th gp rc ri khi mun s dng hai hm n bi v khng bit handle ca cc thnh phn iu khin con. Chng ta ch bit handle ca cc thnh phn iu khin con khi nhn c thng ip WM_COMMAND. gii quyt c vng mc trn, trong Windows cung cp mt hm ly handle ca ca s con khi bit c nh danh ID ca n bng hm.

hwndCtrl = GetDlgltem (hDlg, id); // hDlg l handle ca hp thoi

C th ly r rh danh ID ra thnh phn in khin rnn khi hit r handle ra n bng hm sau.

id = GetWindowLong (hwndCtrl, GWL_ID);

Tuy nhin, chng ta c th qun l ID ca cc thnh phn iu khin con, cn handle l do Windows cp ngu nhin, do vic dng handle nhn v ID ca cc thnh phn iu khin con l t dng n.

Khi hp thoi nhn c thng ip WM_COMAND th chng ta phi kim tra nt radio no c chn (xc nh mu cn chn), v n hnh b chn cc nt khc bng on lnh sau.

case WM_COMMAND:


{

case IDCJBLACK:

case IDC_RED:

case IDC_GREEN:

case IDC_YELLOW:

case IDC BLUE:

case IDC_MAGENTA:

case IDC_CYAN:

case IDCJWHITE:

Trang 42


iColor = LOWORD (wParam) ;

LP TRNH c TRN

for( i = IDC_BLACK, i < IDC_WHITE,i++)

SendMessage(GetDlgItem(hDlg, i),MB_SETCHECK, i == LOWORD( wParam), 0).

return TRUE ;

}

Trong iColor dng lu gi mu hin hnh c chn. Vng lp for dng kim tra trng thi ca tt c cc nt radio thng qua ID ca chng. Hm GetDlgltem dng ly handle ca nt c chn v lu vo bin i. Hm SendMessage dng gi thng ip MB_SETCHECK ti cc nit radio. Nu word thp ca i s wParam bng ch danh ID ca nt c chn th nt c nh du v cc nt khc s khng c chn.

Ch .Trong cc v d trn thng dng hai nt OK v nt Cancel, hai nt ny c Windows t nh danh mc nh theo th t l IDOK v IDCANCEL. Thng thng ng hp thoi bng cch nhn chut vo mt trong hai nt OK hoc Cancel. Trong Windows, khi nhn nt Enter th Windows lun pht sinh thng ip WM_COMMAND, bt k i tng no ang nhn focus. LOWORD ca i s wParam mang gi tr ID ca nt nhn mc nh (nt OK), ngoi tr c mt nt ang nhn focus (trong trng hp ny th LOWORD ca i s wParam mang ch danh ca nt ang nhn focus). Nu nhn nt Esc hay nhn Ctrl+Break, th Windows gi thng ip WM_COMMAND vi thnh phn LOWORD ca i s wParam c gi IDCANCEL (nh danh mc nh ca nt Cancel). Do khng cn phi x l thm cc phm g ng hp thoi.

Trong v d 2.2 x l hai trng hp khi nhn nt Cancel v nt OK ta dng on chng trnh sau.


{

case IDOK:

iCurrentColor = iColor ;

iCurrentFigure = iFigure ;

EndODialog (hDlg, TRUE) ;

return TRUE ;

case IDCANCEL:

EndDialog (hDlg, FALSE) ;

return TRUE ;

Trang 43


LP TRNH c TRN

>

Hm EndDialog dng kt thc v ng hp thoi.Trong trng hp nhn nt OK th hai gi tr iCurrentColor v gi tr iCurrentFigure c lu li cho ca s cha (c hai bin trn u l bin ton cc). Ch rng, hai gi tr khc bit (TRUE, FALSE) ca i s th hai trong li gi hm EndDalog. Gi tr ny s c ngc v t li gi hm DialogBox trong th tc WndProc.

case WM_COMMAND:

switch (LOWORD(wParam))

{

case IDC_SHOW:

if(DialogBox(hInstance, TEXT("DIALOG"), hwnd, DialogProc))

InvalidateRect (hwnd, NULL, TRUE) ;

return 0 ;

}

break;

C ngha nu hm DialogBox tr v gi tr TRUE, tc nt OK c nhn. Lc th tc WndProc s cp nht li ni dung ca ca s chnh, bng cch ghi li s thay i gi tr ca hai bin ton cc iCirentColor v gi iCurrentFigure dng v li hnh ch nht hay hnh ellipse vi mu c chn l iCurrentColor.

V ngc li nu nhn nt Cancel th gi tr iCuentColor v gi tr iCurrentFigure s khng thay i, tc th tc WndProc s dng li gi c.

Gi tr TRUE hay FALSE thng bo cho ca s chnh bit rng ngi dng t chi hay chp thun ty chn trong hp thoi. V TRUE v FALSE c kiu s nguyn (1,0) nn i s th hai trong li gi hm EndDialog c kiu s nguyn (int). Do kt qu v ca hm ny cng c kiu l s nguyn. V d nu bn bm nt OK th tr tr v ca hm bng 1. Nu bn bm nt Cancel th tr tr v ca hm bng 0, v nu trong chng trnh c s dng nt bm mc nh Inoge th khi bm nt ny tr tr ca hm s l 2.

2.2.I.7. V trong hp thoi

Trong v d 2.2 chng ta dng phng php v trn hp thoi y l cng vic khc thng. By gi ta tm hiu cng vic tin hnh nh th no.

Trong file RESOURCE.RC c thnh phn iu khin l.

Trang 44


LTEXT "",IDC_PAINT, 5, 22, 92, 93

LP TRNH c TRN

Khi chng ta chn nt radio thay i mu, hnh v hay nhn c thng ip WM_PAINT th th tc DialogProc thc hin thao tc v vo thnh phn iu khin ca hp thoi bng hm PaintTheBlock. Hm ny c khai bo nh sau.

PaintTheBlock(hCtrBlock, iColor, iFigure);

Trong hCtrBlock l handle ca thnh phn iu khin c nh danh l IDC_PAINT. Handle ca thnh phn iu khin ny c ly v bi hm.

hCtrBlock=GetDlgItem(hDlg, IDC_PAINT);

Ni dung ca hm PaintTheBlock nh sau.

void PaintTheBlock(HWND hCtrl, int iColor, int iFigure)

{

InvalidateRect(hCtrl, NULL, TRUE);

UpdateWinDow(hCtrl);

PaintWinDow(hCl, iColor, iFigure);

}

Hm InvalidateRect(hCl, NULL, TRUE) v UpdateWindow(hCtrl) c nhim v lm cho ca s con cn phi v li. Hm PaintWindow dng v ra mn hnh ellipse hay ch nht. u tin hm ny ly DC (device context) ca thit b c handle l hCl, v v ln thit b ny dng hnh nh cng vi mu t c chn. Kch thc ca ca s con cn v c ly bng hm GetCIientRect.Hm ny tr v kch thc ca vng client cn v theo n v tnh l pixel.

Chng ta v trn vng client ca cc iu khin con ch khng v trc tip ln vng client ca hp thoi. Khi hp thoi nhn c thng ip WM_PAINT th thnh phn iu khin c nh danh IDCJPAINT c v li. Cch x ly thng ip WM_PAINT ging nh th tc x l WndProc ca ca s chnh, nhng th tc x l hp thoi khng gi hm BeginPaint v hm EndPaint bi v n khng t v ln ca s ca chnh n.

Nu mun v hiu ha mt phn t iu kin, tc bin i nt sang trng thi v hiu ha th dng hm.

EnableWindow(hwndCtrl, bEnable);

i s hwndCtrl l ch danh ca thnh phn iu khin mun v hiu ha, thnh phn th hai l bEnable mang hai gi tr TRUE hay FALSE, nu thnh phn ny mang gi tr FALSE

Trang 45

NGN NG LP TRNH LP TRNH c TRNWINDOWSth iu khin ny c v hiu ha, cn ngc li nu thnh phn ny mang gi tr TRUE th iu khin c hiu ha tr li.

2.2.2. H p thoi khng trng thi

Trong phn n tho lun loi hp thoi, th nht l hp thoi trng thi, v by gi tip tc tho lun n loi hp thoi th hai, hp thoi khng trng thi (modeless). hiu r cch s dng cng nh nhng thao tc trn hp thoi khng trng thi, chng ta th t tm hiu qua cc mc sau.

2.2.2.I. S khc nhau gia hp thoi trng thi v hp thoi khng trng thi

Ip thoi khng trng thi khc vi hp thoi trng thi ch. Sau khi hin th hp thoi khng trng thi chng ta c th chuyn thao tc n cc ca s khc m khng cn ng hp thoi dng ny li. iu ny thun tin i vi ngi dng khi ngi dng mun trc quan cc s thao tc cng mt lc. V d nh trnh son tho Studio Deverloper bn c th thao tc qua li gia hai hp thoi, l hp thoi bn cn thit k v mt hp thoi cha cc loi iu khin m bn dng thit k. v i cch lm ny gip ngi dng c quan hn so vi cch ch cho php ngi dng ch thao tc trn mt ca s.

s dng hm DialogBox gi hp thoi trng thi v ch nhn c kt qu tr v khi hp thoi ny b ng cng vi hm DialogBox kt thc. Gi tr tr v ca hm ny do i s th hai ca hm kt thc hp thoi (EndDialog) quy nh. Cn i vi hp thoi khng trng thi th c to ra bng hm.

hD lgM odeless=C reateD ialog(hInstance, szTemplate, hwndParent, DialogProc);

Nhng hm ny tr quyn iu khin v cho ni gi ngay lp tc v gi tr v l handle ca ca hp thoi hin hnh. V c th c nhiu ca s thao tc cng mt lc nn bn 1C handle ny d dng truy cp khi bn cn.

Phi t ch WS_VISIBLE cho hp thoi khng ng thi, bng cch chn mc More Styles trong ca s Properties ca hp thoi. Nu nh khng bt ch VISIBLE ln th chng trnh phi c cu lnh ShowWindow sau li gi hm CreateDialog khi mun hin th hp thoi dng ny ln mn hnh.

hDlgModeless=CreateDialog(hInstance, szTemplate, hwndParent, DialogProc);

ShowW iiHlow(liDlgM odeless,SW _SHOW );

Cc thng ip gi n hp thoi dng modal do trnh qun l Windows iu khin cng khc vi cc thng ip gi n hp thoi dng modeless phi i qua hng i ca chng trnh chnh. Bi v cc thng ip ca hp thoi dng modeless dng chung vi cc thng ip ca ca s chng trnh chnh. Nh vy chng ta phi lc ra thng ip no l thng ip gi n hp thoi khi thao tc trn hp thoi t trong vng lp nhn thng ip.

Trang 46

NGN NG LP TRNH LP TRNH c TRNWINDOWS lm c iu ny chng ta dng handle ca hp thoi (la ong bin ton cc) c tr v t li gi hm CreateDialog v chuyn hng chng bng on lnh nh sau.

while(GetMessage(&msg, NULL, 0, 0))

{

if (hDlgModeless==0 II IIsDialogMessage (hDlgModeless, &msg);

{

TranslateMessage(&msg);

DispatchMessage(&msg);

}

}

Nu thng ip ly ra t hng i dnh cho hp thoi th hm IsDialogMessage kim tra v gi n cc th tc x l hp thoi. V lc ny hm v gi tr TRUE, cn ngc li th hm v gi tr FALSE. Nu dng thm chc nng phm tng tc th on chng nh trn c vit li nh sau.

whUe(GetMessage(&msg, NULL, 0, 0))

{

if (hDlgModeless==0 II !IsDialogMessage(hDlgModeless, &msg);

{

if(TranslateAccelerator (hwnd, hAccel, Stmsg)

{

TranslateMessage(&msg);

DispatchMessage(&msg);

>

}

>

Nn ch rng bin hDlgModeless lun mang gi tr 0 cho n lc c mt hp thoi c khi to bng cu lnh CreateDialog th gi tr ca n mi c thay i. Khi ca s hp thoi b hy nh t hDlgModeless v gi tr 0. iu ny gip Windows khng gi nhm thng ip x l n cc ca s khc. kt thc v ng hp thoi dng Modeless bn dng hm DestroyWindow ch khng phi dng hm EndDialog nh hp thoi dng Modal.

Trang 47


2.22.2. V d v hp thoi khng khng trng thi

minh ha cch dng hp thoi khng trng thi (modeless) ta xt v d 2.3. Chng trnh v d 2.3 sau khi chy c kt qu nh sau.

Hnh 2.6 Minh ha hp thoi khng trng thi

Khi dng chut chn loi hnh v trn radio button, loi hnh v c chn s v cng lc ln control nh ca hp thoi v ca s chnh. Dng chut chn mu t cho hnh v c chn, bng cch r chut ln 3 thanh cun Scrollbar.

Chng trnh minh ha (V d 2.3) :

*OMODELESS.CPP (trch dn)

void PaintWindow (HWND hwnd, int iColorQ, int iFigure)

{

HBRUSH hBrush ;

HDC hdc ;

RECT rect ;

hdc = GetDC(hwnd) ;

GetClientRect (hwnd, &rect) ;

hBrush = CreateSolidBrush(RGB(iColor[0], iColor[l], iColor[2]));

hBrush = (HBRUSH) SelectObject (hdc, hBrush) ;

if (iFigure == IDC_RECT)

Rectangle (hdc, rect.left, rect.top, rect.right, rect.bottom) ;

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else

Ellipse(hdc, rect.left, rect.top, rect.right, rect.bottom);

DeleteObject (SelectObject (hdc, hBrush));

ReleaseDC (hwnd, hdc);

}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAMIParam)

{

switch (message)

{

case WM_PAINT:

PaintTheBlock(hwnd, iColor, iFigure);

return 0 ;

case WM_DESTROY:

DeleteObject((HGDIOBJ)SetClassLong(hwnd, GCL_HBRBACKGROUND,(LONG)GetStockObject(WHITE JBRUSH)));

PostQuiiMessage (0);

return 0 ;

}

return DefWindowProc (hwnd, message, wParam, IParam);

}

void PaintTheBlock (HWND hCtt], int iColor[], int iFigure)

{

InvalidateRect (hCl, NULL, TRUE);

UpdateWindow (hCl);

PaintWindow (hCl, iColor, iFigure);

}

Trang 49


BOOL CALLBACK ColorScrDlg (HWND hDlg, UINT message, WPARAM wParam, LPARAMlParam)

{

HWND hwndParent, hCtrl;

static HWND hClBlock;

int iClID, ilndex;

switch (message)

{

case WM_INli DIALOG:

hClBlock = GetDlgltem (hDlg, IDC_PAINT);

for (iClID = 10; iCtrllD < 13 ; iCtrlID++)

{

hCtrl = GetDlgltem (hDlg, iCtrllD);

PaintTheBlock (hClBlock, iColor, Figure);

PaintTheBlock (hwndParent, Color, iFigure);

SetScrolIRange (hCtrl, SB_CTL, 0,255, FALSE);

SetScrollPos(hQrl, SB_CTL, 0, FALSE);

}

return TRUE;

case WM_COMMAND:

{

switch( LOWORD(wParam))

{

case IDC_RECT:

case IDC_ELLIPSE:

iFigure = LOWORD(wParam);

hwndParent = GetParent (hDlg);

Trang 50


CheckRadioButton(hDlg, IDCJRECT, IDC_ELLIPSE, LOWORD (wParam)) ;

PaintTheBlock(hCtrlBlock, iColor, iFigure);

PaintTheBlock (hwndParent, iColor, iFigure);

return TRUE;

}

break;

>

case WM_VSCROLL :

hCtrl = (HWND) IParam ;

iClID = GetWindowLong (hCtrl, GWL_ID);

ilndex = Ctrl ID - 10;

hwndParent = GetParent (hDlg);

PaintTheBlock (hCttlBlock, iColor, iFigure);

PaintTheBlock (hwndParent, iColor, Figure);


{

case SB_PAGEDOWN:

iColorfilndexJ += 15;

case SBJLINEDOWN:

iColor[iIndex] = min (255, iColor[iIndex] + 1);

break;

case SBJPAGEUP:

iColor[iIndex] -= 15;

case SBJLINEUP :

iColor[iIndex] = max (0, iColor[iIndex] - 1);

break;

Trang 51


case SB_TOP:

iColor[iIndex] = 0 ;

break;

case SB_BOTTOM :

iColorfilndex] = 255;

break;

case SBJTHUMBPOSITION:

case SB_THUMBTRACK:

iColor[iIndex] = HIWORD (wParam);

break;

default:

return FALSE;

>

SetScrollPos(hCtrl, SB_CTL, iColor[iIndex], TRUE);

SetDlgltemlnt (hDlg, CtrlID + 3, iColor[iIndex], FALSE);

InvalidateRect(hwndParent,NULL,TRUE);

DeleteObject ( (HGDIOBJ)SetClassLong( hwndParent, GCL_HBRBACKGROUND, (LONG) CreateSoIidBrush( RGB(iColor[0], iColor[l], iColor[2])) ) ) ;

return TRUE;

case WM_PAINT:

PaintTheBlock(hCtrlBlock, iColor, iFigure);

break;

>

return FALSE;

}

Trang 52


2.3. MENU

LP TRNH c TRN

Trong giao din ng dng Windows, thnh phn quan trng thng khng th thiu l menu ca chng trnh. Menu xut hin ngay di thanh tiu ca chng trnh ng dng. Ngoi ra trong mt s ng dng thanh menu c th di chuyn c.

Tht ra menu cng kh n gin, v chng c t chc thnh cc nhm n thanh chnh (File, Edit, View,...), mi mc lit k trong menu chnh c th cha mt hay nhiu mc lit k gi l menu popup hay dropdown, v vi mi mc lit k trong menu popup ny c th c cc mc con ca n,....

Cc mc lit k n menu c th dng kch hot mt lnh, hay chn trng thi (check, uncheck). Cc mc lit k trn menu c 3 dng: c hiu lc (enabled), khng c hiu lc (disabled), v mu xm (grayed), v i quan im lp trnh th ta ch cn hai trng thi l c hiu lc v khng c hiu lc m thi, do trng thi mu xm s ch cho ngi dng bit l trng thi ca mc lit k c hiu lc hay khng. V vy khi vit chng trnh nhng mc no khng c hiu lc th ta thit lp ng thi mu xm, khi ngi dng s bit rng mc lit k khng c hiu lc.

2.3.1. T h i t lp Menu

to mt menu v a vo chng trnh bao gm cc bc sau:

*To menu ong tp tin ti nguyn *.RC: to menu ong tp tin ti nguyn, thng c 2 cch chnh l: dng mt trnh son tho m tp tin ti nguyn v son tho theo cu trc tp tin RC cung cp cho ti nguyn menu. Thng thng, cch ny t s dng, v cc mi trng pht trin c trn Windows (Borland c for Windows, Visual c ) u cung cp cc cng c cho php to menu mt cch d dng.

*Ci t menu vo ca s ca chng trnh ng dng: phn ny n gin l khi nh ngha lp ca s ta thit lp thuc tnh IpszMenuName ca eau trc lp WNDCLASS bng tn menu c khai bo trong tp tin ti nguyn.

V d : wndclass.lpszMenuName = "MENU1";

Ngoi ra, c th ci t menu vo ca s bng cch dng lnh :

hMenu = LoadMenu ( hlnstance, TEXT("MENU1") );

Lnh ny s tr v mt nh danh ca menu c np, khi c c nh danh menu ny th khi a vo ca s c 2 cch sau:

*Trong hm to ca s CreateWindow, tham s th 9 ca hm l nh danh cho menu, thit lp tham s ny l nh danh ca menu va to.

Trang 53


hwnd = CreateWindow ( TEXT("MyClass"), TEXT("Window Caption"), w s_ 0 VERLAPPEDWINDOW, c w _ u SEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, hMenu, hlnstance, NULL );

*Khi gi hm to ca s CreateWindow, tham s th 9 c thit lp NULL, sau trong chng trnh dng lnh: SetMenu(hWnd, hMenu); thit lp menu cho ca s.

*Thm cc on chng tnh x l menu: Windows pht sinh thng ip WM_COMMAND v gi n chng trnh khi ngi dng chn mt mc lit k c hiu lc trn thanh menu. Khi ch cn x l thng ip WM_COMMAND bng cch kim a 16 bit thp ca tham s wParam l xc nh c ID ca mc lit k no trn menu c chn.

2.3.2. V d minh h a Menu

*Tp tin ti nguyn cha khai bo menu : MENUDEMO.RC

MENUDEMO MENU DISCARDABLE

BEGIN

POPUP "&File"

BEGIN

MENUITEM "&New", IDM_FILE_NEW

MENUITEM "&Open", IDM_FILE_OPEN

MENUTTEM "&Save, IDM_FILE_SAVE

MENUITEM "Save &As..., IDM_FILE_SAVE_AS

MENUITEM SEPARATOR

MENUITEM "E&xit", IDM_APP_EXIT

END

POPUP "&Edit"

BEGIN

MENUITEM "&Undo", IDM_EDIT_UNDO

MENUITEM SEPARATOR

MENUITEM "C&ut", IDM_EDIT_CUT

MENUITEM "&Copy", IDM_EDIT_COPY

Trang 54


MENUITEM "&Paste", IDM_EDIT_PASTE

MENUITEM "De&lete", IDM_EDIT_CLEAR

END

POPUP "&Background"

BEGIN

MENUITEM "&White", IDM_BKGND_WHITE, CHECKED

MENUTTEM "&Light Gray", IDM_BKGND_LTGRAY

MENUITEM "&Gray", IDM_BKGND_GRAY

MENUITEM "&Dark Gray", IDM_BKGND_DKGRAY

MENUITEM "&Black", IDM_BKGNDJBLACK

END

POPUP "&Help"

BEGIN

MENUTTEM "&Help...", IDM_APP_HELP

MENUITEM "&AboutIDM_APP_ABOUT

END

END

*Tp tin tiu cha cc nh ngha : MENUDEMO.H

#define IDM_FILE_NEW 40001

#define EDM_FILE_OPEN 40002

#define IDM_FILE_SAVE 40003

#define IDM_FILE_SAVE_AS 40004

#define IDM_APP_EXIT 40005

#define IDM_EDIT_UNDO 40006

#define IDM_EDIT_CUT 40007

#define IDM_EDIT_COPY 40008

Trang 55


#define IDMJEDITJPASTE 40009

#define IDM_EDIT_CLEAR 40010

#define IDM_BKGND_WHITE 40011

#define IDM_BKGND_LTGRAY 40012

#define IDM_BKGND_GRAY 40013

#define IDM_BKGND_DKGRAY 40014

#define IDM_BKGND_BLACK 40015

#define EDM_APP_HELP 40018

#define IDM_APP_ABOUT 40019

*Tp tn cha m ngun : MENUDEMO.C

#indude

#indude "menudemo.h"


/* Khai bo tn dng chung cho ccti nguyn trong chng trnh.*/

TCHAR szAppName[] = TEXT ("MenuDemo");

int WINAPI WinMain (HINSTANCE hlnstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)

{

HWND hwnd;

MSG msg;

WNDCLASS wndclass;

wndclass.style = CS_HREDRAW I CS_VREDRAW;

wndclass.lpfnWndProc = WndProc;

wndclass.cbClsExtta = 0 ;

wndclass.cbWndExtra = 0 ;

wndclass.hlnstance = hlnstance;

wndclass.hlcon = LoadIcon(NULL, IDI_APPLICATION);

Trang 56


wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);

wndclass.hbrBackground =

(HBRUSH)GetStockObject(WHITE_BRUSH);

wndclass.lpszMenuName = szAppName;

wndclass.lpszClassName = szAppName;

if (IRegisterClass (&wndclass))

{

MessageBox(NULL, TEXT("This program reqmres Windows "), szAppName, MB_ICONERROR);

return 0 ;

}

hwnd = Create Window (szAppName, TEXT("Menu Demonsttation"), WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hlnstance, NULL);

ShowWindow (hwnd, iCmdShow);

UpdateWindow (hwnd);

while (GetMessage(&msg, NULL, 0, 0))

{



}

return msg.wParam;

}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAMIParam)

{

/* Khao bo danh sch cc mu chi t, cc hng ny c nh ngha trong file WINGDI.H */

static int idColor[5] = { W H ITEJB R U SH , LTGRAY_BRUSH, GRAY_BRU SH, DKGRAY_BRUSH, BLACKJBRUSH };

Trang 57


static int iSelection = IDM_BKGND_WHITE ;

HMENU hMenu;

switch (message)

{

case WM_COMMAND:

hMenu = GetMenu (liwnd); //L y nh danh ca menu

switch (LOWORD (wParam)) //K im tra nh danh mc chn

{

case IDM_FILE_NEW:

case IDM_FILE_OPEN:

case IDM_FILE_SAVE:

case IDM_FILE_SAVE_AS:

MessageBeep(O); //Pht ra ting ku bp

return 0 ;

case IDM_APP_EXIT:

/*Gi thng ip ng ng dng li*/

SendMessage (hwnd, WM_CLOSE, 0, 0);

return 0 ;

case IDM_EDIT_UNDO:

case IDM_EDIT_CUT:

case IDM_EDIT_COPY:

case IDM_EDIT_PASTE:

case IDM_EDIT_CLEAR:

MessageBeep (0);

return 0 ;

case IDM_BKGND_WHITE:

Trang 58


case IDM_BKGND_LTGRAY:

case IDM_BKGND_GRAY:

case IDM_BKGND_DKGRAY:

case IDM_BKGND_BLACK:

/* B check ca mc chn trc */

CheckMenuItem(hMenu,iSelection, MF_UNCHECKED);

iSelection = LOWORD (wParam); /*Ly ID mc mi*/

/* Check mc chn mi*/

CheckMenuItem (hMenu, iSelection, MF_CHECKED);

/* Thit lp mu tng ng vi mc chn mi*/

SetClassLong(hwnd,GCL_HBRBACKGROUND, (LONG) GetStockObject(idCoior[iSeiection- IDM_BKGND_w h i t e ] ) ) ;

InvalidateRect (hwnd, NULL, TRUE);

return 0 ;

case IDM_APP_HELP:

MessageBox(hwnd, TEXT("Help not yet implemented!"), szAppName, MB_ICONEXCLAMATION I MB_OK) ;

return 0 ;

case IDM_APP_ABOUT:

MessageBox (hwnd, TEXT ("Menu Demonsttation Program\n (c) Charles Petzold, 1998"), szAppName, MBJCONINFORMATION I MB_OK);

return 0 ;

}

break;

case WM_DESTROY:

PostQuitMessage(O) ;

return 0 ;

}

Trang 59


return DefWindowProc(hwnd, message, wParam, IParam);

>

Chng 3

CC I TNG IU KHIN

3.1. M U

Cc i tng iu khin (control) l cc thnh phn tng tc c quan, th hin r c ch giao tip ha gia ng dng v ngi dng. Nh cc i tng ny, cc chng trnh ng dng trong Windows tr nn thn thin v d dng. V th, chng l cc thnh phn c bn khng th thiu trong hu ht cc hg dng.

Trong chng ny, chng ta s tm hiu cc to lp v x l cho cc i tng iu khin thng qua cc lp (class) sau :

Lp Button (nt bm).

Trang 60


Lp Static (tnh). Lp Edit Box (son tho). Lp List Box danh sch. Lp Combo Box. Lp Scroll Bar (thanh cun).

3.2. GI I THIU TNG QUAN

Mt kiu iu khin c xem nh l mt ca s con. C th to nhiu ca s con trong cng mt ca s cha. Cc ca s con xc nh handle ca s ca cha bng cch gi hm :

hwndParent = GetParent (hwnd);

hwnd l handle ca ca s con cn ly hadadle ca ca s cha. V khi ly c handle ca ca s cha, ca s con c quyn gi cc thng ip n ca s cha thng qua hm.

SendMessage(hwndParent, message, wParam, lParam);

message l thng ip cn gi n th tc x l ca ca s cha. wParam l ch danh 1D ca ca s con, cn lParam ghi li trng thi ca ca s con.

v y chng ta c th to mt thnh phn iu khin dng ca s con hay cn gi l "child window control", c a s con c nhim v x l cc thng ip nh bn phm, thng ip chut v thng bo cho ca s cha khi trng thi ca ca s con thay i. Nh vy ca s con tr thnh cng c giao tip (cho php nhp v xut) gia ngi dng vi chng trnh.

Tuy chng ta c th to ra mt ca s con cho chnh mnh, nhng chng ta nn tn dng cc lp ca s con c Windows nh ngha sn hay cn gi l nhng kiu iu khin chun. Nhng kiu iu khin chun ny thng l cc nt bm (button), hp kim tra (check box), hp son tho (edit box), hp danh sch (list box), combo box, cc thanh cun v chui ch. V d mun to ra mt nt bm trn mn hnh ch cn gi hm CreateWindows, m chng cn phi quan tm n cch v, cch nhn chut hay l chp khi b kch hot. Tt c iu ny u do Windows x l. iu quan trng lphi chn thng ip WM_COMMAND ca cc iu khin x l thng ip ny theo nhng mc ch khc nhau.

Cc kiu iu khin con thng c dng trong hp thoi. Nh minh ha trong chng 2, cc iu khin nhn hp thoi im ca s cha. Tuy nhin, cng c th to cc kiu iu khin con trc tip trn vng ca s chnh, bng cch gi hm CreateWindow v iu chnh v tr cng vi kch thc ca n cho thch hp bng hm MoveWindow. Th tc x l thng ip ca ca s cha gi cc thng ip n cc khiu iu khin con, v ngc li cc child window control gi cc thng ip yu cu ca s cha x l cc thng ip .

to mt ca s ng dng bnh thng. u tin phi ng k lp ca s bng hm Register Class. Tip theo l khi to lp ng k thng qua hm CreateWindow. Cn

Trang 61

NGN NG LP TRNH LP TRNH c TRNWINDOWStrng hp mun to mt lp c nh ngha sn th khng cn ng k cho lp ca s con mun to.

s dng cc kiu iu khin trc tip trn ca s chnh i hi cc tc v cp thp hn so vi dng cc kiu iu khin trn hp thoi. V cc kiu iu khin to ra trn ca s chnh khng c h tr cc tin ch. V d nh chng ta khng th s dng phm bm tab chuyn focus gia cc kiu iu khin vi nhau.

3.3. LP BUTTON

tm hiu cc kiu iu khin, xem xt v d 3.1 sau. Trong v d ny to ra 9 ca s con chun trn mt ca s cha nh hnh 3.1.

JaJxJ

PUSHBUTTON n ie s > d u e

DEFPUSHBUTTON

r CHECKBOX w AUTOCHECKBOX

r RADIOBUTTON

r 3STATE w AUT03STATE

GROUPBOX[

WH_COMMAND

W M COM M AND

WM_COMMAND

WM_COMMAND

WM_COMMAND

WM_COMMAND

WM_COMMAND

UM COMMAND

0 000 -0 0 0 0

0 000 -00020000-00030000-00040000-00050000-00060000-0008

0019-0288 0 0 3ft-01A80020- 0214 0 0 1ft-0278 0019-0274 001A-028 0019-0272 0019-0276

Hnh 3.1 Minh ha cc lp Button

Nhp chut vo cc nt, lc cc nt s gi thng ip WM_COMMAND n th tc x l thng ip WndProc ca ca s cha. Th tc WndProc x l v in ra mn hnh cc thng s lParam v wParam ca thng ip gi ti ny.Trong lParam l handle ca ca s con gi thng ip n ca s cha. wParam c hai phn LOWORD v HIWORD, LOWORD cho bit ID ca ca s con, HIWORD l m thng bo. M thng bo nt bm l mt trong nhng gi tr sau.

nh danh m thng bo Button Gi tr

BN_CLICKED 0

BN_PAINT 1

BN_HILETE hay BN_PUSHED 2

BNJJNHILITE hay BNJJNPHUSHED 3

Trang 62

NGN NG LP TRNHWINDOWS

LP TRNH c TRN

BN_DISABLE 4

BNJDOUBLECLICKED hay BN_DBCLICK 5

BN_SETFOCUS 6

BN_KILLFOCUS 7

Bng 3.1 nh danh m thng bo Button

Khng bao gi thy c cc gi tr ca nt bm, ch bit rng gi t 1 n 4 dnh cho kiu button BS_USERBUTTON, gi tr 5 dnh cho kiu BS_RADIOBTTON, BS_AUTORADIOBUTTON, BS_OWNEDRAW, hay cc nt bm khc nu nt bm bao gm kiu BS_NOTYFY. Gi tr 5,6 dnh cho cc kiu nt bm bao gm c c NOTYFY. Sau y l chng trnh chnh.

*CONTROLl.CPP (trch dn)

struct

{

int iStyle;

TCHAR *szText;

}

button[ ] =

{

BSJPUSHBUTTON, TEXT ("PUSHBUTTON"),

BS_DEFPUSHBUTTON, TEXT ("DEFPUSHBUTTON"),

BS_CHECKBOX, TEXT ("CHECKBOX"),

BS_AUTOCHECKBOX, TEXT ("AUTOCHECKBOX"),

BS_RADIOBUTTON, TEXT ("RADIOBUTTON"),

BS_3STATE, TEXT ("3STATE"),

BS_AUT03STATE, TEXT ("AUT03STATE"),

BS_GROUPBOX, TEXT ("GROUPBOX"),

BS_AUTORADIOBUTTON, TEXT ("AUTORADIO")

Trang 63


};

#define NUM (sizeof(button) / sizeof(button[0]))


LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAMlParam)

{

static HWND hwndButton[NUM];

static RECT rect;

static TCHAR szTopO = TEXT("message wParam IParam"),

szUnd[] = TEXT("___________________"),

szFormat[] = TEXT("%-16s%04X-%04X %04X-%04X"),

szBuffer[50];

static int cxChar, cyChar;

HDC hdc;

PAINTSTRUCT p s;

int i ;

switch (message)

{

case WM_CREATE:

cxChar = LOWORD(GetDialogBaseUnitsQ);

cyChar = HrWORD(GetDialogBaseUnitsO);

for (i = 0 ; i < NUM ; i++)

hwndButton[i] = CreateWindow(TEXT("button"), button[i].szText, WS_CHILD|WS_VISIBLE| bunon[i].iStyle, cxChar, cyChar*(l+2'i'i)> 20*cxChar, 7*cyChar/4, hwnd, (HMENU)i, ((LPCREATESTRUCT)lParam)->Mnstance, NULL);

return 0 ;

case WM_SIZE :

rect.left = 24*cxChar;

Trang 64


rect.top = 2*cyChar ;

LP TRNH c TRN

rect.right = LOWORD(lParam);

rect.bottom = HIWORD(lParam);

return 0 ;

case WM_PAINT:

InvalidateRect (hwnd, &rect, TRUE);

hdc = BeginPaint (hwnd, &ps);

SelectObject(hdc,GetStockObject(SYSTEM_FiXED_FONT));

SetBkMode (hdc, TRANSPARENT);

TextOut (hdc, 24 * cxChar, cyChar, szTop, lstrlen (szTop)); TextOut (hdc, 24 * cxChar, cyChar, szUnd, lstrlen (szUnd));

EndPaint (hwnd, &ps);

return 0 ;

case WM_DRAWITEM:

case WM_COMMAND:

ScrollWindow (hwnd, 0, -cyChar, &rect, &rect);

hdc = GetDC (hwnd);

SelectObject(hdc, GetStockObject(SYSTEM_FiXED_FONT));

TextOut (hdc, 24*cxChar, cyChar*(rect.bottom/cyChar-l), szBuffer, wsprintf (szBuffer, szFormat, message==WM_DRAWITEM ? TEXT ("WMJDRAWITEM"): TEXT ("WM_COMMAND"), HIWORD (wParam), LOWORD (wParam), HIWORD (IParam), LOWORD (IParam)));

ReleaseDC (hwnd, hdc);

ValidateRect (hwnd, &rect);

break;

case WM_DESTROY:

PostQuitMessage(O);

return 0 ;

}

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return DefWindowProc (hwnd, message, wParam, lParam) ;

}

to ra mt child window control bn dng cu trc CreateWindow vi cc thng s nh sau.

Tn lp : TEXT ("button") Text ca s : Button[i].szText Kiu ca s : WS_CHILD I WS_VISIBLE I button[i].iStyle DV tr X : cxChar V tr y : cyChar*( l+2*i ) Chiu rng : 20*xChar Chiu cao : 7*yChar*4 DHandle ca s cha : hwnd Ch danh ca ca s con : (HMENU) i Th qun Handle : ((LPCREATESTRUCT) lParam-> hlnstance, NULL) ; Cc thng s thm : NULL

Trong tn lp l c nh. Tn ca s do chng ta t. Kiu ca s s dng l WS_CHILD, WS_VISIBLE v mt ong 9 kiu button (BSJPUSHBUTTON, BS_CHECKBOX, .).

Tip theo l 4 thng s xc nh v tr X, v y, kch thc theo chiu rng, kch thc chiu cao ca ca s con trn vng client ca ca s cha. hwnd l handle ca ca s cha. ID l ch danh ca mi ca s con (mi ca s con c duy nht mi s ID). ID ny phi p kiu HMENU ch nh trnh n. lParam thc cht l mt con tr n cu trc LPCREATESTRCT c thnh phn hlnstance. D mun ly th qun hlnstance th phi p kiu lParam.

3.3.1. Lp Push Button

Trong v d 3.1 c hai Push Button c to ra bng hm CreateWindow vi kch thc v v tr c xc nh bi ngi lp trnh. Cc Push Button c s dng bt tt mt hnh ng tc thi ch khng gi c trng thi bt hay tt lu di nh checkbox c. Trn y l hai kiu ca s BSJPUSHBUTTON v BSJDEFBUTTON (kiu nt bm mc nh). Hai kiu ny khi thit k th khc nhau nhng khi s dng th n c chc nng hon ton ging nhau. Khi nhn chut vo nt ny th nt ny gi thng ip WM_COMMAND n ca s cha vi m thng bo BN_CLICK. C th tc ng n nt bm ny bng cch gi hm.

SendMessage( hwndButton, BM_SETSTASE, 1, 0 );

N u m un nt n h n ny tr l i trn g thi bnh th ng th g i hm :

SendMessage(hwndButton, BM_SETSTASE, 0, 0 );

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hwndButton l nh danh ca ca s con c v bi hm CreateWindow.

3.3.2. Lp Check Box

Mt check box l l mt hp vung km theo ch. Thng thng ch nm bn tri ca hp. Tuy nhin, cng c th t ch nm bn phi bng cch thm vo kiu BS_LEFTTEXT khi to mt button. Cc check box cho php ngi dng chn cc ty chn, n hot ng nh mt cng tc. C hai loi check box thng dng l BS_CHECKBOX v BS_AUTCHECKBOX. Khi s dng loi BS_CHECKBOX, chng ta t t du check box bng cch gi n kiu iu khin ny thng ip BS_SETCHECK. Thng s wParam trong hm SendMessage c t gi 1 to nh du, v bng 0 khi mun hy nh du.Ly trng thi ca mt check box bng cch gi n kiu iu khin ny thng ip BM_GETCHECK. Dng on chng trnh sau bt tt du check khi x l thng ip WM_COMMAND c gi n t cac kiu iu khin.

SendMessage((HWND)lParam, BM_SETCHECK, (WPARAM)!SendMessage( (HWND)lParam, BM_GETCHECK, 0, 0), 0);

Ch ton t ! (NOT) ng c hm SendMessage. Gi tr lParam l handle ca ca s con gi n ca s cha trong thng ip WM_COMMAND. Mun bit trng thi ca check box no th gi ti n thng ip BM_GETCHECK. khi ng mt check box loi BS_CHECKBOX vi trng thai c nh du, bng cch gi n n mt thng ip BM_SETCHECK theo cu trc.

SendMessage (hwndButton,BM_SETCHECK, 1, 0);

Cn check box

lap trinh c tren windows 5536

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