ObjRef Class

Definition

Namespace:

System.Runtime.Remoting

Assembly:

mscorlib.dll

Stores all relevant information required to generate a proxy in order to communicate with a remote object.

public ref class ObjRef : System::Runtime::Serialization::IObjectReference, System::Runtime::Serialization::ISerializable

[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
[System.Security.SecurityCritical]
public class ObjRef : System.Runtime.Serialization.IObjectReference, System.Runtime.Serialization.ISerializable

[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
[<System.Security.SecurityCritical>]
type ObjRef = class
    interface IObjectReference
    interface ISerializable

Public Class ObjRef
Implements IObjectReference, ISerializable

Inheritance

Object

ObjRef

Attributes

SerializableAttribute ComVisibleAttribute SecurityCriticalAttribute

Implements

IObjectReference ISerializable

Examples

The following code example demonstrates the use of a custom ObjRef. To view the activation code that tests the custom ObjRef, see the example for the RegisterWellKnownServiceType method.

// a custom ObjRef class that outputs its status
[System::Security::Permissions::SecurityPermissionAttribute(
   System::Security::Permissions::SecurityAction::Demand, 
   Flags=System::Security::Permissions::SecurityPermissionFlag::SerializationFormatter)]
[System::Security::Permissions::SecurityPermissionAttribute
(System::Security::Permissions::SecurityAction::Demand, 
Flags=System::Security::Permissions::SecurityPermissionFlag::Infrastructure)]	
[System::Security::Permissions::SecurityPermissionAttribute
(System::Security::Permissions::SecurityAction::InheritanceDemand, 
Flags=System::Security::Permissions::SecurityPermissionFlag::Infrastructure)]
public ref class MyObjRef: public ObjRef
{
private:

   // only instantiate using marshaling or deserialization
   MyObjRef(){}

public:
   MyObjRef( MarshalByRefObject^ o, Type^ t )
      : ObjRef( o, t )
   {
      Console::WriteLine( "Created MyObjRef." );
      ORDump();
   }

   MyObjRef( SerializationInfo^ i, StreamingContext c )
      : ObjRef( i, c )
   {
      Console::WriteLine( "Deserialized MyObjRef." );
   }

   virtual void GetObjectData( SerializationInfo^ s, StreamingContext c ) override
   {
      // After calling the base method, change the type from ObjRef to MyObjRef
      ObjRef::GetObjectData( s, c );
      s->SetType( GetType() );
      Console::WriteLine( "Serialized MyObjRef." );
   }

   virtual Object^ GetRealObject( StreamingContext context ) override
   {
      if ( IsFromThisAppDomain() || IsFromThisProcess() )
      {
         Console::WriteLine( "Returning actual Object^ referenced by MyObjRef." );
         return ObjRef::GetRealObject( context );
      }
      else
      {
         Console::WriteLine( "Returning proxy to remote Object^." );
         return RemotingServices::Unmarshal( this );
      }
   }

   void ORDump()
   {
      Console::WriteLine( " --- Reporting MyObjRef Info --- " );
      Console::WriteLine( "Reference to {0}.", TypeInfo->TypeName );
      Console::WriteLine( "URI is {0}.", URI );
      Console::WriteLine( "\nWriting EnvoyInfo: " );
      if ( EnvoyInfo != nullptr )
      {
         IMessageSink^ EISinks = EnvoyInfo->EnvoySinks;
         while ( EISinks != nullptr )
         {
            Console::WriteLine( "\tSink: {0}", EISinks );
            EISinks = EISinks->NextSink;
         }
      }
      else
            Console::WriteLine( "\t {no sinks}" );

      Console::WriteLine( "\nWriting ChannelInfo: " );
      for ( int i = 0; i < ChannelInfo->ChannelData->Length; i++ )
         Console::WriteLine( "\tChannel: {0}", ChannelInfo->ChannelData[ i ] );
      Console::WriteLine( " ----------------------------- " );
   }

};

// a class that uses MyObjRef
public ref class LocalObject: public MarshalByRefObject
{
public:

   // overriding CreateObjRef will allow us to return a custom ObjRef
   [System::Security::Permissions::SecurityPermissionAttribute
   (System::Security::Permissions::SecurityAction::LinkDemand,
   Flags=System::Security::Permissions::SecurityPermissionFlag::Infrastructure)]
   virtual ObjRef^ CreateObjRef( Type^ t ) override
   {
      return gcnew MyObjRef( this,t );
   }
};

// a custom ObjRef class that outputs its status
public class MyObjRef : ObjRef {

   // only instantiate using marshaling or deserialization
   private MyObjRef() { }

   public MyObjRef(MarshalByRefObject o, Type t) : base(o, t)  {
      Console.WriteLine("Created MyObjRef.");
      ORDump();
   }

   public MyObjRef(SerializationInfo i, StreamingContext c) : base(i, c) {
      Console.WriteLine("Deserialized MyObjRef.");
   }

   public override void GetObjectData(SerializationInfo s, StreamingContext c) {
      // After calling the base method, change the type from ObjRef to MyObjRef
      base.GetObjectData(s, c);
      s.SetType(GetType());
      Console.WriteLine("Serialized MyObjRef.");
   }

   public override Object GetRealObject(StreamingContext context) {

      if ( IsFromThisAppDomain() || IsFromThisProcess() ) {
         Console.WriteLine("Returning actual object referenced by MyObjRef.");
         return base.GetRealObject(context);
      }
      else {
         Console.WriteLine("Returning proxy to remote object.");
         return RemotingServices.Unmarshal(this);
      }
   }

   public void ORDump() {

      Console.WriteLine(" --- Reporting MyObjRef Info --- ");
      Console.WriteLine("Reference to {0}.", TypeInfo.TypeName);
      Console.WriteLine("URI is {0}.", URI);
      Console.WriteLine("\nWriting EnvoyInfo: ");

      if ( EnvoyInfo != null) {

         IMessageSink EISinks = EnvoyInfo.EnvoySinks;
         while (EISinks != null) {
            Console.WriteLine("\tSink: " + EISinks.ToString());
            EISinks = EISinks.NextSink;
         }
      }
      else
        {
            Console.WriteLine("\t {no sinks}");
        }

        Console.WriteLine("\nWriting ChannelInfo: ");
      for (int i = 0; i < ChannelInfo.ChannelData.Length; i++)
         Console.WriteLine ("\tChannel: {0}", ChannelInfo.ChannelData[i]);
      Console.WriteLine(" ----------------------------- ");
   }
}

// a class that uses MyObjRef
public class LocalObject : MarshalByRefObject {
   // overriding CreateObjRef will allow us to return a custom ObjRef
   public override ObjRef CreateObjRef(Type t) {
      return new MyObjRef(this, t);
   }
}

' a custom ObjRef class that outputs its status
<PermissionSet(SecurityAction.Demand, Name:="FullTrust")> _
Public Class MyObjRef
   Inherits ObjRef

   ' only instantiate using marshaling or deserialization
   Private Sub New()
   End Sub

   Public Sub New(ByVal o As MarshalByRefObject, ByVal t As Type)
      MyBase.New(o, t)
      Console.WriteLine("Created MyObjRef.")
      ORDump()
   End Sub

   Public Sub New(ByVal i As SerializationInfo, ByVal c As StreamingContext)
      MyBase.New(i, c)
      Console.WriteLine("Deserialized MyObjRef.")
   End Sub

   Public Overrides Sub GetObjectData(ByVal s As SerializationInfo, ByVal c As StreamingContext)
      ' After calling the base method, change the type from ObjRef to MyObjRef
      MyBase.GetObjectData(s, c)
      s.SetType([GetType]())
      Console.WriteLine("Serialized MyObjRef.")
   End Sub

   Public Overrides Function GetRealObject(ByVal context As StreamingContext) As [Object]
      If IsFromThisAppDomain() Or IsFromThisProcess() Then
         Console.WriteLine("Returning actual object referenced by MyObjRef.")
         Return MyBase.GetRealObject(context)
      Else
         Console.WriteLine("Returning proxy to remote object.")
         Return RemotingServices.Unmarshal(Me)
      End If
   End Function

   Public Sub ORDump()
      Console.WriteLine(" --- Reporting MyObjRef Info --- ")
      Console.WriteLine("Reference to {0}.", TypeInfo.TypeName)
      Console.WriteLine("URI is {0}.", URI)

      Console.WriteLine(ControlChars.Cr + "Writing EnvoyInfo: ")
      If Not (EnvoyInfo Is Nothing) Then
         Dim EISinks As IMessageSink = EnvoyInfo.EnvoySinks
         Dim count As Integer = 0
         While Not (EISinks Is Nothing)
            Console.WriteLine(ControlChars.Tab + "Interated through sink #{0}", (count = count + 1))
            EISinks = EISinks.NextSink
         End While
      Else
         Console.WriteLine(ControlChars.Tab + " {no sinks}")
      End If
      Console.WriteLine(ControlChars.Cr + "Writing ChannelInfo: ")
      Dim i As Integer
      For i = 0 To ChannelInfo.ChannelData.Length - 1
         Console.WriteLine(ControlChars.Tab + "Channel: {0}", ChannelInfo.ChannelData(i))
      Next i
      Console.WriteLine(" ----------------------------- ")
   End Sub
   
End Class


' a class that uses MyObjRef
<PermissionSet(SecurityAction.Demand, Name:="FullTrust")> _
Public Class LocalObject
   Inherits MarshalByRefObject

   ' overriding CreateObjRef will allow us to return a custom ObjRef
   Public Overrides Function CreateObjRef(ByVal t As Type) As ObjRef
      Return New MyObjRef(Me, t)
   End Function

End Class

Remarks

A ObjRef is a serializable representation of an object that extends MarshalByRefObject (MBR). A ObjRef is used to transfer an object reference across a AppDomain boundary. Creating a ObjRef for an object is known as marshaling. You can create a ObjRef (marshal a MarshalByRefObject) either explicitly, by registering the MBR object with the remoting infrastructure (see RemotingConfiguration and RemotingServices.Marshal), or implicitly, by passing an MBR object as a parameter when calling a remote object. Remoting uses ObjRef objects to store and transmit all the relevant information about the MarshalByRefObject being remoted.

The ObjRef contains information that describes the Type and class of the object being marshaled, its exact location, and communication-related information on how to reach the remoting subdivision where the object is located.

After a class implementing MarshalByRefObject is marshaled, the ObjRef that represents it is transferred through a channel into another application domain, possibly in another process or computer. When the ObjRef is deserialized (see XML and SOAP Serialization) in the target application domain, it is parsed to create a transparent proxy for the remote MBR object. This operation is known as unmarshaling.

A transparent proxy is an object that 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 run-time class of type RealProxy. The RealProxy implements a part of the functionality needed to forward the operations from the transparent proxy.

A proxy object can be used without regard to any remoting subdivisions within a AppDomain. Applications need not distinguish between proxy references and object references. However, service providers dealing with issues such as activation, lifetime management, and transactions need to make such distinctions.

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.

Constructors

ObjRef()	Initializes a new instance of the ObjRef class with default values.
ObjRef(MarshalByRefObject, Type)	Initializes a new instance of the ObjRef class to reference a specified MarshalByRefObject of a specified Type.
ObjRef(SerializationInfo, StreamingContext)	Initializes a new instance of the ObjRef class from serialized data.

Properties

ChannelInfo	Gets or sets the IChannelInfo for the ObjRef.
EnvoyInfo	Gets or sets the IEnvoyInfo for the ObjRef.
TypeInfo	Gets or sets the IRemotingTypeInfo for the object that the ObjRef describes.
URI	Gets or sets the URI of the specific object instance.

Methods

Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetObjectData(SerializationInfo, StreamingContext)	Populates a specified SerializationInfo with the data needed to serialize the current ObjRef instance.
GetRealObject(StreamingContext)	Returns a reference to the remote object that the ObjRef describes.
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsFromThisAppDomain()	Returns a Boolean value that indicates whether the current ObjRef instance references an object located in the current AppDomain.
IsFromThisProcess()	Returns a Boolean value that indicates whether the current ObjRef instance references an object located in the current process.
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)

See also

• ISerializable
• Marshal(MarshalByRefObject)
• Unmarshal(ObjRef)
• RealProxy