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
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:
- SecurityPermission for operating with infrastructure code. Demand value: SecurityAction.LinkDemand; Permission Value: SecurityPermissionFlag.Infrastructure
- SecurityPermission for operating with infrastructure code. Demand value: SecurityAction.InheritanceDemand; Permission Value: SecurityPermissionFlag.Infrastructure
See Also
ProxyAttribute Members | System.Runtime.Remoting.Proxies Namespace | RealProxy