best practices for.net development thom robbins [email protected]
TRANSCRIPT
What we will cover Design Guidelines Memory Management Data Access Internet Services Threading Security
Session Prerequisites
Know VB .NET or C# Be familiar with .NET Base Class Libraries Be familiar with XML
Level 300Level 300
So Why This Presentation? You know you are a VB programmer if…
You ever had to use the On Error Goto statement You never wrote a multi-threaded app
You know you are a C++ programmer if… You ever had to check an HRESULT every 2 lines
of code 30% of your code was releasing objects from
memory You know you are an ADO programmer if…
You had to convert between a Recordset and a DOM and transform the XML 5 times in between
Agenda
.NET Design Guidelines Memory Management Data Access Internet Services Threading Security
.NET Design GuidelinesNaming Conventions
Hungarian notation is out! For public interfaces, use PascalCasing For private members, use camelCasing Use underscore “_” character to denote
private class members Use camelCasing for all method
parameters
.NET Design GuidelinesNaming Conventions
public class Customer{ private string _password;
public void SetPassword(string newPassword) { _password = newPassword; }}
.NET Design GuidelinesClass Members Usage
Don’t use public fields, use properties No write-only methods, use a method Only use properties for setting and
retrieving values Allow properties to be set in any order Use a consistent ordering and naming
pattern for parameters
.NET Design GuidelinesBase Classes vs. Interfaces
Only Use Interfaces When… Unrelated classes want to support a protocol Aggregation is not appropriate
Provide class customization through protected methods
.NET Design GuidelinesError Raising and Handling
Exceptions are not for flow of control! Exceptions are “exceptional” Derive new custom exceptions from the
ApplicationException class
Agenda
.NET Design Guidelines Memory Management Data Access Internet Services Threading Security
Memory Management Avoid Finalize() Only use Finalize() with Dispose()
public void Dispose(){ // Clean up unmanaged resources GC.SuppressFinalize(this);}
protected override void Finalize(){ // Clean up unmanaged resources base.Finalize();}
Agenda
.NET Design Guidelines Memory Management Data Access Internet Services Threading Security
Data AccessAccessing Relational Data
Always use the optimal Managed Provider Pick DataReader over DataSet when
possible Used stored procedures when possible Do NOT use dynamic connection strings
Data AccessXML Data
Use the XmlDataDocument for XML/DataSet integration DOM DataSet DOM
Don’t use DOM if you don’t need it Only necessary for in-memory editing
XmlReader is faster than DOM
Agenda
.NET Design Guidelines Memory Management Data Access Internet Services Threading Security
Internet ServicesWebClient vs. WebRequest
Use WebClient for simple request and response operations
Use WebRequest for more complex operations Asynchronous requests, setting headers, etc.
Internet ServicesGeneral Tips
Don’t pass credentials every time Don’t type cast to descendant classes,
such as HttpRequest In ASP.NET, use the asynchronous
methods of GetResponse and GetResponseStream
As a good starting point, use 8 connections/processor
Agenda
.NET Design Guidelines Memory Management Data Access Internet Services Threading Security
ThreadingGeneral Tips
Avoid locks whenever possible Don’t provide static methods that alter
static state Asynchronous invocation via delegates
are the preferred threading mechanism
ThreadingSynchronization
Starvation is caused by multiple threads contending for a resource
The Monitor and ReaderWriterLock are designed to prevent starvation
Agenda
.NET Design Guidelines Memory Management Data Access Internet Services Threading Security
SecurityKey Concepts
Use the principal of least privilege Don’t run Visual Studio with admin
privileges Use the runas utilityC:\>runas /user:timmc\administrator cmd
Enter password for timmc\administrator:
Lock down security policy early
SecurityCode Access Security
Access to a protected resource The ability to perform a protected
operation
FileIOPermission permission = new FileIOPermission(PermissionState.None);permission.AllLocalFiles = FileIOPermissionAccess.Read;
SecurityRole-Based Security
Imperative (old way)
public void DoTransaction(){ IPrincipal principal = Thread.CurrentPrincipal; if (!principal.IsInRole("Managers")) { throw new SecurityException("Not a " + "manager!"); } // OK, do the transaction...}
SecurityRole-Based Security
Imperative (new way)
public void DoTransaction(){ PrincipalPermission permission = new PrincipalPermission(null, "Managers"); permission.Demand(); // Now do the transaction...}
SecurityRole-Based Security
Declarative
[PrincipalPermission(SecurityAction.Demand, Role="Managers")]void DoTransaction(){ // this time, really // do the transaction...}
Session Summary Write consistent and predictable code Write scalable, high-performance code Write secure code
For More Information… MSDN Web site at
msdn.microsoft.com
MSDN Magazine http://msdn.microsoft.com/msdnmag/
For More Information… Microsoft Visual Studio .NET Documentation
http://msdn.microsoft.com/library/default.asp?url=/nhp/Default.asp?contentid=28000451
MS PressEssential Resources for Developers
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