A reference constriant : Type constaint « Generic « C# / CSharp Tutorial

Home
C# / CSharp Tutorial
1.Language Basics
2.Data Type
3.Operator
4.Statement
5.String
6.struct
7.Class
8.Operator Overload
9.delegate
10.Attribute
11.Data Structure
12.Assembly
13.Date Time
14.Development
15.File Directory Stream
16.Preprocessing Directives
17.Regular Expression
18.Generic
19.Reflection
20.Thread
21.I18N Internationalization
22.LINQ
23.GUI Windows Forms
24.Windows Presentation Foundation
25.Windows Communication Foundation
26.Workflow
27.2D
28.Design Patterns
29.Windows
30.XML
31.XML LINQ
32.ADO.Net
33.Network
34.Directory Services
35.Security
36.unsafe
C# / C Sharp
C# / C Sharp by API
C# / CSharp Open Source
C# / CSharp Tutorial » Generic » Type constaint 
18.21.1.A reference constriant
using System; 
 
class MyClass 

 
class Test<T> where T : class 
  T obj; 
 
  public Test() { 
    // Here T must be a reference type, 
    // which can be assigned the value null. 
    obj = null
  

 
class MainClass 
  public static void Main() { 
    // The following is OK because MyClass is a class. 
    Test<MyClass> x = new Test<MyClass>()
 
    // The next line is in error because int is a value type. 
    // Test<int> y = new Test<int>(); 
  
}
18.21.Type constaint
18.21.1.A reference constriant
18.21.2.A value type constriant
18.21.3.Static Field Per Closed Type
www.java2java.com | Contact Us
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.