RealProxy Class (System.Runtime.Remoting.Proxies)

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Microsoft Visual Studio 2008/.NET Framework 3.5

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.NET Framework Class Library

RealProxy Class

Updated: November 2007

Provides base functionality for proxies.

Namespace: System.Runtime.Remoting.Proxies
Assembly: mscorlib (in mscorlib.dll)

Syntax

Visual Basic (Declaration)

<ComVisibleAttribute(True)> _
<SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags := SecurityPermissionFlag.Infrastructure)> _
<SecurityPermissionAttribute(SecurityAction.InheritanceDemand, Flags := SecurityPermissionFlag.Infrastructure)> _
Public MustInherit Class RealProxy

Visual Basic (Usage)

Dim instance As RealProxy

[ComVisibleAttribute(true)]
[SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.Infrastructure)]
[SecurityPermissionAttribute(SecurityAction.InheritanceDemand, Flags = SecurityPermissionFlag.Infrastructure)]
public abstract class RealProxy

Visual C++

[ComVisibleAttribute(true)]
[SecurityPermissionAttribute(SecurityAction::LinkDemand, Flags = SecurityPermissionFlag::Infrastructure)]
[SecurityPermissionAttribute(SecurityAction::InheritanceDemand, Flags = SecurityPermissionFlag::Infrastructure)]
public ref class RealProxy abstract

/** @attribute ComVisibleAttribute(true) */
/** @attribute SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.Infrastructure) */
/** @attribute SecurityPermissionAttribute(SecurityAction.InheritanceDemand, Flags = SecurityPermissionFlag.Infrastructure) */
public abstract class RealProxy

JScript

public abstract class RealProxy

Remarks

The RealProxy class is the abstract base class from which proxies must derive.

A client that uses an object across any kind of a remoting boundary is actually using a transparent proxy for the object. The transparent proxy provides the illusion that the actual object resides in the client's space. It achieves this by forwarding calls made on it to the real object using the remoting infrastructure.

The transparent proxy is itself housed by an instance of a managed runtime class of type RealProxy. The RealProxy implements a part of the functionality that is needed to forward the operations from the transparent proxy. Note that a proxy object inherits the associated semantics of managed objects such as garbage collection, support for fields and methods, and can be extended to form new classes. The proxy has a dual nature: it acts as an object of the same class as the remote object (transparent proxy), and it is a managed object itself.

A proxy object can be used without regard to any remoting subdivisions within a AppDomain.

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.

Notes to Inheritors:

When you inherit from RealProxy, you must override the Invoke method.

Examples

Visual Basic

' Create a custom 'RealProxy'.
Public Class MyProxy
   Inherits RealProxy
   Private myURIString As String
   Private myMarshalByRefObject As MarshalByRefObject

   <PermissionSet(SecurityAction.LinkDemand)> _
   Public Sub New(ByVal myType As Type)
      MyBase.New(myType)
      ' RealProxy uses the Type to generate a transparent proxy.
      myMarshalByRefObject = CType(Activator.CreateInstance(myType), MarshalByRefObject)
      ' Get 'ObjRef', for transmission serialization between application domains.
      Dim myObjRef As ObjRef = RemotingServices.Marshal(myMarshalByRefObject)
      ' Get the 'URI' property of 'ObjRef' and store it.
      myURIString = myObjRef.URI
      Console.WriteLine("URI :{0}", myObjRef.URI)
   End Sub 'New

<SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags:=SecurityPermissionFlag.Infrastructure)> _
   Public Overrides Function Invoke(ByVal myIMessage As IMessage) As IMessage
      Console.WriteLine("MyProxy.Invoke Start")
      Console.WriteLine("")

      If TypeOf myIMessage Is IMethodCallMessage Then
         Console.WriteLine("IMethodCallMessage")
      End If
      If TypeOf myIMessage Is IMethodReturnMessage Then
         Console.WriteLine("IMethodReturnMessage")
      End If
      Dim msgType As Type
      msgType = CObj(myIMessage).GetType
      Console.WriteLine("Message Type: {0}", msgType.ToString())
      Console.WriteLine("Message Properties")
      Dim myIDictionary As IDictionary = myIMessage.Properties
      ' Set the '__Uri' property of 'IMessage' to 'URI' property of 'ObjRef'.
      myIDictionary("__Uri") = myURIString
      Dim myIDictionaryEnumerator As IDictionaryEnumerator = CType(myIDictionary.GetEnumerator(), _
                                                                    IDictionaryEnumerator)

      While myIDictionaryEnumerator.MoveNext()
         Dim myKey As Object = myIDictionaryEnumerator.Key
         Dim myKeyName As String = myKey.ToString()
         Dim myValue As Object = myIDictionaryEnumerator.Value

         Console.WriteLine(ControlChars.Tab + "{0} : {1}", myKeyName, myIDictionaryEnumerator.Value)
         If myKeyName = "__Args" Then
            Dim myObjectArray As Object() = CType(myValue, Object())
            Dim aIndex As Integer
            For aIndex = 0 To myObjectArray.Length - 1
               Console.WriteLine(ControlChars.Tab + ControlChars.Tab + "arg: {0} myValue: {1}", _
                                                              aIndex, myObjectArray(aIndex))
             Next aIndex
         End If

         If myKeyName = "__MethodSignature" And Not Nothing Is myValue Then
            Dim myObjectArray As Object() = CType(myValue, Object())
            Dim aIndex As Integer
            For aIndex = 0 To myObjectArray.Length - 1
               Console.WriteLine(ControlChars.Tab + ControlChars.Tab + "arg: {0} myValue: {1}", _
                                                           aIndex, myObjectArray(aIndex))
            Next aIndex
         End If
      End While

        Dim myReturnMessage As IMessage

        myIDictionary("__Uri") = myURIString
        Console.WriteLine("__Uri {0}", myIDictionary("__Uri"))

        Console.WriteLine("ChannelServices.SyncDispatchMessage")
        myReturnMessage = ChannelServices.SyncDispatchMessage(CObj(myIMessage))

        ' Push return value and OUT parameters back onto stack.
        Dim myMethodReturnMessage As IMethodReturnMessage = CType(myReturnMessage, IMethodReturnMessage)
        Console.WriteLine("IMethodReturnMessage.ReturnValue: {0}", myMethodReturnMessage.ReturnValue)

        Console.WriteLine("MyProxy.Invoke - Finish")

        Return myReturnMessage
    End Function 'Invoke
End Class 'MyProxy

// Create a custom 'RealProxy'.
public class MyProxy : RealProxy
{
   String myURIString;
   MarshalByRefObject myMarshalByRefObject;   

   [PermissionSet(SecurityAction.LinkDemand)]
   public MyProxy(Type myType) : base(myType)
   {
      // RealProxy uses the Type to generate a transparent proxy.
      myMarshalByRefObject = (MarshalByRefObject)Activator.CreateInstance((myType));
      // Get 'ObjRef', for transmission serialization between application domains.
      ObjRef myObjRef = RemotingServices.Marshal(myMarshalByRefObject);
      // Get the 'URI' property of 'ObjRef' and store it.
      myURIString = myObjRef.URI;
      Console.WriteLine("URI :{0}", myObjRef.URI);
   }

   [SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags=SecurityPermissionFlag.Infrastructure)]
   public override IMessage Invoke(IMessage myIMessage)
   {
      Console.WriteLine("MyProxy.Invoke Start");
      Console.WriteLine("");

      if (myIMessage is IMethodCallMessage)
         Console.WriteLine("IMethodCallMessage");

      if (myIMessage is IMethodReturnMessage)
         Console.WriteLine("IMethodReturnMessage");

      Type msgType = myIMessage.GetType();
      Console.WriteLine("Message Type: {0}", msgType.ToString());
      Console.WriteLine("Message Properties");
      IDictionary myIDictionary = myIMessage.Properties;
      // Set the '__Uri' property of 'IMessage' to 'URI' property of 'ObjRef'.
      myIDictionary["__Uri"] = myURIString;
      IDictionaryEnumerator myIDictionaryEnumerator = 
         (IDictionaryEnumerator) myIDictionary.GetEnumerator();

      while (myIDictionaryEnumerator.MoveNext())
      {
         Object myKey = myIDictionaryEnumerator.Key;
         String myKeyName = myKey.ToString();
         Object myValue = myIDictionaryEnumerator.Value;

         Console.WriteLine("\t{0} : {1}", myKeyName, 
            myIDictionaryEnumerator.Value);
         if (myKeyName == "__Args")
         {
            Object[] myObjectArray = (Object[])myValue;
            for (int aIndex = 0; aIndex < myObjectArray.Length; aIndex++)
               Console.WriteLine("\t\targ: {0} myValue: {1}", aIndex, 
                  myObjectArray[aIndex]);
         }

         if ((myKeyName == "__MethodSignature") && (null != myValue))
         {
            Object[] myObjectArray = (Object[])myValue;
            for (int aIndex = 0; aIndex < myObjectArray.Length; aIndex++)
               Console.WriteLine("\t\targ: {0} myValue: {1}", aIndex, 
                  myObjectArray[aIndex]);
         }
      }

      IMessage myReturnMessage;

      myIDictionary["__Uri"] = myURIString;
      Console.WriteLine("__Uri {0}", myIDictionary["__Uri"]);

      Console.WriteLine("ChannelServices.SyncDispatchMessage");
      myReturnMessage = ChannelServices.SyncDispatchMessage(myIMessage);

      // Push return value and OUT parameters back onto stack.

      IMethodReturnMessage myMethodReturnMessage = (IMethodReturnMessage)
         myReturnMessage;
      Console.WriteLine("IMethodReturnMessage.ReturnValue: {0}", 
         myMethodReturnMessage.ReturnValue);

      Console.WriteLine("MyProxy.Invoke - Finish");

      return myReturnMessage;
   }
}

Visual C++

// Create a custom 'RealProxy'.
public ref class MyProxy: public RealProxy
{
private:
   String^ myURIString;
   MarshalByRefObject^ myMarshalByRefObject;

public:
   MyProxy( Type^ myType )
      : RealProxy( myType )
   {

      // RealProxy uses the Type to generate a transparent proxy.
      myMarshalByRefObject = dynamic_cast<MarshalByRefObject^>(Activator::CreateInstance(myType));

      // Get 'ObjRef', for transmission serialization between application domains.
      ObjRef^ myObjRef = RemotingServices::Marshal( myMarshalByRefObject );

      // Get the 'URI' property of 'ObjRef' and store it.
      myURIString = myObjRef->URI;
      Console::WriteLine( "URI :{0}", myObjRef->URI );
   }

   virtual IMessage^ Invoke ( IMessage^ myIMessage ) override 
    {
      Console::WriteLine( "MyProxy.Invoke Start" );
      Console::WriteLine( "" );
      if ( dynamic_cast<IMethodCallMessage^>(myIMessage) )
            Console::WriteLine( "IMethodCallMessage" );

      if ( dynamic_cast<IMethodReturnMessage^>(myIMessage) )
            Console::WriteLine( "IMethodReturnMessage" );

      Type^ msgType = myIMessage->GetType();
      Console::WriteLine( "Message Type: {0}", msgType );
      Console::WriteLine( "Message Properties" );
      IDictionary^ myIDictionary = myIMessage->Properties;

      // Set the '__Uri' property of 'IMessage' to 'URI' property of 'ObjRef'.
      myIDictionary->default[ "__Uri" ] = myURIString;
      IDictionaryEnumerator^ myIDictionaryEnumerator = dynamic_cast<IDictionaryEnumerator^>(myIDictionary->GetEnumerator());
      while ( myIDictionaryEnumerator->MoveNext() )
      {
         Object^ myKey = myIDictionaryEnumerator->Key;
         String^ myKeyName = myKey->ToString();
         Object^ myValue = myIDictionaryEnumerator->Value;
         Console::WriteLine( "\t{0} : {1}", myKeyName, myIDictionaryEnumerator->Value );
         if ( myKeyName->Equals( "__Args" ) )
         {
            array<Object^>^myObjectArray = (array<Object^>^)myValue;
            for ( int aIndex = 0; aIndex < myObjectArray->Length; aIndex++ )
               Console::WriteLine( "\t\targ: {0} myValue: {1}", aIndex, myObjectArray[ aIndex ] );
         }

         if ( (myKeyName->Equals( "__MethodSignature" )) && (nullptr != myValue) )
         {
            array<Object^>^myObjectArray = (array<Object^>^)myValue;
            for ( int aIndex = 0; aIndex < myObjectArray->Length; aIndex++ )
               Console::WriteLine( "\t\targ: {0} myValue: {1}", aIndex, myObjectArray[ aIndex ] );
         }
      }

      IMessage^ myReturnMessage;
      myIDictionary->default[ "__Uri" ] = myURIString;
      Console::WriteLine( "__Uri {0}", myIDictionary->default[ "__Uri" ] );
      Console::WriteLine( "ChannelServices.SyncDispatchMessage" );
      myReturnMessage = ChannelServices::SyncDispatchMessage( myIMessage );

      // Push return value and OUT parameters back onto stack.
      IMethodReturnMessage^ myMethodReturnMessage = dynamic_cast<IMethodReturnMessage^>(myReturnMessage);
      Console::WriteLine( "IMethodReturnMessage.ReturnValue: {0}", myMethodReturnMessage->ReturnValue );
      Console::WriteLine( "MyProxy.Invoke - Finish" );
      return myReturnMessage;
   }
};

// Create a custom 'RealProxy'.
/** @attribute SecurityPermission(SecurityAction.Demand, Flags = SecurityPermissionFlag.Infrastructure) */
public class MyProxy extends RealProxy
{
    private String myURIString;
    private MarshalByRefObject myMarshalByRefObject;

    public MyProxy(Type myType)
    {
        super(myType);

        // RealProxy uses the Type to generate a transparent proxy.
        myMarshalByRefObject = 
            (MarshalByRefObject)(Activator.CreateInstance(myType));

        // Get 'ObjRef', for transmission serialization between 
        // application domains.
        ObjRef myObjRef = RemotingServices.Marshal(myMarshalByRefObject);

        // Get the 'URI' property of 'ObjRef' and store it.
        myURIString = myObjRef.get_URI();
        Console.WriteLine("URI :{0}", myObjRef.get_URI());
    } //MyProxy

    public IMessage Invoke(IMessage myIMessage)
    {
        Console.WriteLine("MyProxy.Invoke Start");
        Console.WriteLine("");
        if (myIMessage instanceof IMethodCallMessage) {
            Console.WriteLine("IMethodCallMessage");
        }

        if (myIMessage instanceof IMethodReturnMessage) {
            Console.WriteLine("IMethodReturnMessage");
        }

        Type msgType = myIMessage.GetType();

        Console.WriteLine("Message Type: {0}", msgType.ToString());
        Console.WriteLine("Message Properties");

        IDictionary myIDictionary = myIMessage.get_Properties();

        // Set the '__Uri' property of 'IMessage' to 'URI' property of 'ObjRef'.
        myIDictionary.set_Item("__Uri", myURIString);

        IDictionaryEnumerator myIDictionaryEnumerator = 
            (IDictionaryEnumerator)(myIDictionary.GetEnumerator());
        while (myIDictionaryEnumerator.MoveNext()) {
            Object myKey = myIDictionaryEnumerator.get_Key();
            String myKeyName = myKey.ToString();
            Object myValue = myIDictionaryEnumerator.get_Value();
            Console.WriteLine("\t{0} : {1}", myKeyName, 
                myIDictionaryEnumerator.get_Value());

            if (myKeyName.Equals("__Args")) {
                Object myObjectArray[] = (Object[])myValue;
                for (int aIndex = 0; aIndex < myObjectArray.length; aIndex++) {
                    Console.WriteLine("\t\targ: {0} myValue: {1}", 
                        (Int32)aIndex, myObjectArray.get_Item(aIndex));
                }
            }

            if (myKeyName.Equals("__MethodSignature") && null != myValue) {
                Object myObjectArray[] = (Object[])myValue;
                for (int aIndex = 0; aIndex < myObjectArray.length; aIndex++) {
                    Console.WriteLine("\t\targ: {0} myValue: {1}", 
                        (Int32)aIndex, myObjectArray.get_Item(aIndex));
                }
            }
        }

        IMessage myReturnMessage;
        myIDictionary.set_Item("__Uri", myURIString);
        Console.WriteLine("__Uri {0}", myIDictionary.get_Item("__Uri"));
        Console.WriteLine("ChannelServices.SyncDispatchMessage");
        myReturnMessage = ChannelServices.SyncDispatchMessage(myIMessage);

        // Push return value and OUT parameters back onto stack.
        IMethodReturnMessage myMethodReturnMessage = 
            (IMethodReturnMessage)myReturnMessage;
        Console.WriteLine("IMethodReturnMessage.ReturnValue: {0}", 
            myMethodReturnMessage.get_ReturnValue());
        Console.WriteLine("MyProxy.Invoke - Finish");
        return myReturnMessage;
    } //Invoke
} //MyProxy

Permissions

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

Inheritance Hierarchy

System..::.Object
System.Runtime.Remoting.Proxies..::.RealProxy

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.

Platforms

Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

Reference

RealProxy Members

System.Runtime.Remoting.Proxies Namespace

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