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IMessage Interface

Contains communication data sent between cooperating message sinks.

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

'Declaration
<ComVisibleAttribute(True)> _
Public Interface IMessage
'Usage
Dim instance As IMessage

Message sinks that use IMessage can be placed in the client sink chains or in the server sink chains. A message object is passed from message sink to message sink through the chain, and carries a set of named properties such as action identifiers, envoy information, and parameters.

An object that implements the IMessage interface meets the minimum qualifications to be considered a message object. The exact object received by a message sink does not have to be passed on to the next sink, but this is often the case.

Although the objects in the property bag do not have to be serializable, the message sink implementer needs to consider this, since the properties that flow out of the application domain must be serializable.

' 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 __gc class MyProxy : public RealProxy
{
   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(S"URI :{0}", myObjRef->URI);
   }

   IMessage* Invoke(IMessage* myIMessage)
   {
      Console::WriteLine(S"MyProxy.Invoke Start");
      Console::WriteLine(S"");

      if (dynamic_cast<IMethodCallMessage*>(myIMessage))
         Console::WriteLine(S"IMethodCallMessage");

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

      Type* msgType = myIMessage->GetType();
      Console::WriteLine(S"Message Type: {0}", msgType);
      Console::WriteLine(S"Message Properties");
      IDictionary* myIDictionary = myIMessage->Properties;
      // Set the '__Uri' property of 'IMessage' to 'URI' property of 'ObjRef'.
      myIDictionary->Item[S"__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(S"\t{0} : {1}", myKeyName, 
            myIDictionaryEnumerator->Value);
         if (myKeyName->Equals(S"__Args"))
         {
            Object* myObjectArray[] = (Object*[])myValue;
            for (int aIndex = 0; aIndex < myObjectArray->Length; aIndex++)
               Console::WriteLine(S"\t\targ: {0} myValue: {1}", __box(aIndex), 
                  myObjectArray[aIndex]);
         }

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

      IMessage* myReturnMessage;

      myIDictionary->Item[S"__Uri"] = myURIString;
      Console::WriteLine(S"__Uri {0}", myIDictionary->Item[S"__Uri"]);

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

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

      IMethodReturnMessage* myMethodReturnMessage = dynamic_cast<IMethodReturnMessage*>(myReturnMessage);
      Console::WriteLine(S"IMethodReturnMessage.ReturnValue: {0}", 
         myMethodReturnMessage->ReturnValue);

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

      return myReturnMessage;
   }
};

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, 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.

.NET Framework

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