utpa – fall 2011

CSCI 3327 Visual Basic CSCI 3327 Visual Basic Chapter 10: Windows Forms Chapter 10: Windows Forms

GUI: A Deeper LookGUI: A Deeper Look

UTPA – Fall 2011

Objectives

• In this chapter, you will– Learn the design of graphical user interfaces

(GUIs)– Get familiar with programming mouse and

keyboard events– Know how to create and manipulate controls

• E.g., Panel, ToolTip, Menu, MonthCalendar, LinkLabel, and CheckedListBox,

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Controls

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Controls and Components

• ToolBox

• A form is a container for controls and components

• Visual Studio generates code of controls and components when you drag them onto the form

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Common Properties of a Form

• AcceptButton– Button that is clicked when Enter key is pressed

• AutoScroll

• CancelButton– Button that is clicked when Esc key is pressed

• FormBorderStyle

• Font

• Text5

Common Methods & Events of a Form

• Methods– Close

• Close a form and release its resources

– Hide• Hide a form without releasing or destroying its

resources

– Show• Display a hidden form

• Events– Load

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Create Event Handlers

• In the code editor window– Select a control (e.g. button) from the left combo

box– Select an event from the right combo box– Code is generated

automatically

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Control Properties and Methods

• Properties– TabIndex

• Controls receive focus in the order of TabIndex property

– TabStop• Prevent the control from receiving the focus in this manner

– Enabled vs. Visible

• Methods– Focus– Hide: set Visible property to False– Show: set Visible property to True

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GroupBoxes and Panels

• Properties of GroupBox– Controls– Text

• Properties of Panel– AutoScroll– BorderStyle– Controls

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Example 14.12: PanelDemo.vb

• URL:– http://media.pearsoncmg.com/ph/esm/deitel/

vb_htp_2010/codeexamples.html

• Display the button you clicked on Panel– Hanldes Button1.Click, Button2.Click– The same method for multiple events– Ctype (sender, Button).Text

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Tool Tips

• A helpful text that appears when the mouse hovers over a GUI control

• Drag ToolTip component to form– It appears below the form in the design mode

• Each control will have an extra property– ToolTip on ToolTip1

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Mouse-Event Handling

• Mouse events– Clicks, presses, and moves– For most mouse events, information about the

event is passed to the event-handling method by an object of class MouseEventArgs

• Mouse pointer's x- and y-coordinates

• The mouse button pressed (Right, Left or Middle)

• The number of times the mouse was clicked

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Mouse-Event Handling (cont'd)

• Mouse events– Mouse event with event argument of type EventArgs

• MouseEnter, MouseLeave

– Mouse event with event argument of type MouseEventArgs

• MouseDown, MouseHover, MouseMove, MouseUp

– Class MouseEventArgs properties• Button, Clicks, X, Y

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Example 14.18: Painter.vb

• URL:– http://media.pearsoncmg.com/ph/esm/deitel/

vb_htp_2010/codeexamples.html

• Painter_MouseMove– e As MouseEventArgs

• e.X, e.Y

– g As Graphics = CreateGraphics()– G.FillEllipse(New SolidBrush(Color.BlueViolet),

e.X, e.Y, 4, 4)14

(e.X, e.Y)4

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Keyboard-Event Handling

• Key Events with Event Arguments of Type KeyEventArgs– KeyDown, KeyUp

• Key Events with Event Arguments of Type KeyPressEventArgs– KeyPress

• Class KeyPressEventArgs properties– KeyChar (ASCII character for the key pressed)– Handled (indicating wether the KeyPress event was

handled)• Class KeyEventArgs properties

– Alt, Control, Shift, Handled, KeyCode

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Example 14.20: KeyDemo

• URL:– http://media.pearsoncmg.com/ph/esm/deitel/

vb_htp_2010/codeexamples.html

• ByVal e As KeyPressEventArgs– e.KeyChar

• ByVal e As KeyEventArgs– e.Alt, e.Shift, e.Control– e.KeyCode.ToString(), e.KeyData.ToString(),

e.KeyValue.ToString()

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Menu

• Menu– Shortcut Keys

• Type an ampersand (&) symbol before the character to be underlined

• To display &, use &&– To add shortcut keys for menu items

• Set the ShortcutKeys property– Other types of menu items

• Separator bar• ComboBox• MenuItem• TextBox

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Example 14.25: MenuTest.vb

• URL:– http://media.pearsoncmg.com/ph/esm/deitel/

vb_htp_2010/codeexamples.html

• blackToolStripMenuItem.Checked = True

• displayLabel.Font = New Font("Times New Roman", 14, displayLabel.Font.Style)

• Application.Exit()

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MonthCalendar Control

• Properties– FirstDayOfWeek– MaxDate, MinDate– MaxSelectionCount– SelectionRange

• Event– DateChanged

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Example 14.29: DateTimePicker

• URL:– http://media.pearsoncmg.com/ph/esm/deitel/

vb_htp_2010/codeexamples.html• dropOffDateTimePicker.MinDate=DateTime.Tod

ay• dropOffDateTimePicker.MaxDate=DateTime.Tod

ay.AddYears(1)• Dim dropOffDate As DateTime =

dropOffDateTimePicker.Value– dropOffDate.DayOfWeek=DayOfWeek.Friday– dropOffDate.AddDays(3).ToLongDateString()

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LinkLabel Control

• Display links to other resources• Example 14.31:

– URL:http://media.pearsoncmg.com/ph/esm/deitel/vb_htp_2010/codeexamples.html

• cDriveLinkLabel.LinkClicked– cDriveLinkLabel.LinkVisited = True– Process.Start(“C:\”)– Process.Start(“http://www.deitel.com”)– Process.Start(“notepad”)

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Process.Start(" ")

• Effect of Process.Start(" ")– Start Run

• cmd

• calc

• notepad

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ListBox and CheckedListBox Controls

• ListBox properties– MultiColumn– SelectedIndex

• -1 – no items are selected• If multiple items are selected, one of selected indices is

returned– SelectedIndices

• For multiple selected items– SelectedItem, SelectedItems– SelectionMode: None, One, MultiSimple,

MultiExtended– Sorted: alphabetically, False by default

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ListBox and CheckedListBox Controls (cont'd)

• ListBox methods– ClearSelected– GetSelected

• Take an index as an argument, and return True if the corresponding item is selected

– myListBox.Items.Add(myListItem)

• ListBox Events– SelectedIndexChanged

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ListBox and CheckedListBox Controls (cont'd)

• CheckedListBox properties– CheckedItems

• A collection of items that are checked

– CheckedIndices• A collection of indices for all checked items

– CheckOnClick • False by Default

– SelectionMode• Determine how many items can be checked: One or

None

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ListBox and CheckedListBox Controls (cont'd)

• CheckedListBox Method– GetItemChecked

• Take an index and returns True if the corresponding items is checked

• CheckedListBox Event– ItemCheck

• ItemCheckEventArgs– CurrentValue– Index– NewValue

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Example 14.35: CheckedListBoxTest.vb

• URL:– http://media.pearsoncmg.com/ph/esm/deitel/

vb_htp_2010/codeexamples.html

• itemCheckedListBox.SelectedItem.ToString()

• If e.NewValue = CheckState.Checked

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Multiple Document Interface (MDI) Windows

• Single document interface (SDI) vs. multiple document interface (MDI)

• MDI: Parent and child windows

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MDI parent

MDI child

MDI child

Multiple Document Interface (MDI) Windows (cont'd)

• Specify a form is an MDI container– Set IsMdiContainer property to True

• Create a class for child forms– Solution Explorer Add Windows Form…

• Create a new child form

• Set MdiParent property to the parent form

• Call the child form’s Show method

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Multiple Document Interface (MDI) Windows (cont'd)

• MDI container features– MdiChildren property

• Return an array of child Form references

– ActiveMdiChild property• Return a reference to the active child window

• Tracking child windows in menus– MenuStrip class provides property

MdiWindowListItem• To check which child windows are open in an MDI

container

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Multiple Document Interface (MDI) Windows (cont'd)

• Arrange child windows– Parent form has method LayoutMdi

• Tiled windows (value TileHorizontal or TileVertical)

• Cascaded windows (value Cascade)

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Example 14.42: UsingMDI.vb

• URL:– http://media.pearsoncmg.com/ph/esm/deitel/

vb_htp_2010/codeexamples.html• Dim child = new ChildForm(“XXX”,

“vb2008htp")– child.MdiParent = Me– child.Show()

• Me.LayoutMdi(MdiLayout.Cascade)• Me.LayoutMdi(MdiLayout.TileHorizontal)• Me.LayoutMdi(MdiLayout.TileVertical)

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Animation with the Timer Component

• Timer component generates Tick events at fixed time interval– Timer component has Interval property

• The number of milliseconds between events

– By default, timers are disabled• Set Enabled property to True

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Example 14.47: AnimationDemo.vb

• URL:– http://media.pearsoncmg.com/ph/esm/deitel/

vb_htp_2010/codeexamples.html

• Display a new image every 50 milliseconds– Handles animationTimer.Tick

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