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ProxyAttribute Class

Indicates that an object type requires a custom proxy.

For a list of all members of this type, see ProxyAttribute Members.

System.Object
   System.Attribute
      System.Runtime.Remoting.Proxies.ProxyAttribute

[Visual Basic]
<AttributeUsage(AttributeTargets.Class)>
Public Class ProxyAttribute
   Inherits Attribute
[C#]
[AttributeUsage(AttributeTargets.Class)]
public class ProxyAttribute : Attribute
[C++]
[AttributeUsage(AttributeTargets::Class)]
public __gc class ProxyAttribute : public Attribute
[JScript]
public
   AttributeUsage(AttributeTargets.Class)
class ProxyAttribute extends Attribute

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Remarks

Apply the current attribute to types that need custom proxies. You can use the ProxyAttribute class to intercept the new (New in Visual Basic) statement by deriving from the ProxyAttribute and placing the attribute on a child of ContextBoundObject. (Placing the proxy attribute on a child of MarshalByRefObject is not supported.)

Note   This class makes a link demand and an inheritance demand at the class level. A SecurityException is thrown when either the immediate caller or the derived class does not have infrastructure permission. For details about security demands, see Link Demands and Inheritance Demands.

Example

[Visual Basic] 
<SecurityPermissionAttribute(SecurityAction.Demand, Flags := SecurityPermissionFlag.Infrastructure), _
AttributeUsage(AttributeTargets.Class)>  _
Public Class MyProxyAttribute
   Inherits ProxyAttribute

   Public Sub New()
   End Sub 'New

   ' Create an instance of ServicedComponentProxy
   Public Overrides Function CreateInstance(serverType As Type) As MarshalByRefObject
      Return MyBase.CreateInstance(serverType)
   End Function 'CreateInstance

   Public Overrides Function CreateProxy(objRef1 As ObjRef, serverType As Type, _
               serverObject As Object, serverContext As Context) As RealProxy
      Dim myCustomProxy As New MyProxy(serverType)
      If Not (serverContext Is Nothing) Then
         RealProxy.SetStubData(myCustomProxy, serverContext)
      End If
      If Not serverType.IsMarshalByRef And serverContext Is Nothing Then
         Throw New RemotingException("Bad Type for CreateProxy")
      End If
      Return myCustomProxy
   End Function 'CreateProxy
End Class 'MyProxyAttribute

<MyProxyAttribute()> _
Public Class CustomServer
   Inherits ContextBoundObject

   Public Sub New()
      Console.WriteLine("CustomServer Base Class constructor called")
   End Sub 'New

   Public Sub HelloMethod(str As String)
      Console.WriteLine("HelloMethod of Server is invoked with message : " + str)
   End Sub 'HelloMethod
End Class 'CustomServer

[C#] 
[AttributeUsage(AttributeTargets.Class)]
[SecurityPermissionAttribute(SecurityAction.Demand, Flags=SecurityPermissionFlag.Infrastructure)]
public class MyProxyAttribute : ProxyAttribute
{
   public MyProxyAttribute()
   {
   }
   // Create an instance of ServicedComponentProxy
   public override MarshalByRefObject CreateInstance(Type serverType)
   {  
      return base.CreateInstance(serverType);
   }
   public override RealProxy CreateProxy(ObjRef objRef1,
      Type serverType,
      object serverObject,
      Context serverContext)
   {
      MyProxy myCustomProxy = new MyProxy(serverType);
      if(serverContext != null)
      {
         RealProxy.SetStubData(myCustomProxy,serverContext);
      }
      if((!serverType.IsMarshalByRef)&&(serverContext == null))
      {
         throw new RemotingException("Bad Type for CreateProxy");
      }
      return myCustomProxy;
   }
}

[MyProxyAttribute]
public class CustomServer :ContextBoundObject
{
   public CustomServer()
   {
      Console.WriteLine("CustomServer Base Class constructor called");
   }
   public void HelloMethod(string str)
   {
      Console.WriteLine("HelloMethod of Server is invoked with message : " + str);
   }
}

[C++] 
[AttributeUsage(AttributeTargets::Class)]
[System::Security::Permissions::SecurityPermissionAttribute(System::Security::Permissions::SecurityAction::Demand, Flags=SecurityPermissionFlag::Infrastructure)] 

public __gc class MyProxyAttribute : public ProxyAttribute 
{
public:
    MyProxyAttribute() 
    {
    }
    // Create an instance of ServicedComponentProxy
public:
    MarshalByRefObject* CreateInstance(Type* serverType) 
    {  
        return ProxyAttribute::CreateInstance(serverType);
    }
public:
    RealProxy* CreateProxy(ObjRef* objRef1,
        Type* serverType,
        Object* serverObject,
        Context* serverContext) 
    {
        MyProxy* myCustomProxy = new MyProxy(serverType);
        if (serverContext != 0) 
        {
            RealProxy::SetStubData(myCustomProxy, serverContext);
        }
        if ((!serverType->IsMarshalByRef)&&(serverContext == 0)) {
            throw new RemotingException(S"Bad Type for CreateProxy");
        }
        return myCustomProxy;
    }
};

[MyProxyAttribute]
__gc class CustomServer : public ContextBoundObject 
{
public:
    CustomServer() 
    {
        Console::WriteLine(S"CustomServer Base Class constructor called");
    }
public:
    void HelloMethod(String* str) {
        Console::WriteLine(S"HelloMethod of Server is invoked with message : {0}", str);
    }
};

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Namespace: System.Runtime.Remoting.Proxies

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

Assembly: Mscorlib (in Mscorlib.dll)

.NET Framework Security: 

See Also

ProxyAttribute Members | System.Runtime.Remoting.Proxies Namespace | RealProxy

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