Remoting Example: CallContext
This topic is specific to a legacy technology that is retained for backward compatibility with existing applications and is not recommended for new development. Distributed applications should now be developed using the Windows Communication Foundation (WCF).
This sample uses the CallContext class and the ILogicalThreadAffinative interface to pass data between a remoting client application and a remoting server application.
This application runs on a single computer or across a network. If you want to run this application over a network, you must replace "localhost" in the client configuration with the name of the remote computer.
Caution |
---|
.NET Remoting does not do authentication or encryption by default. Therefore, it is recommended that you take all necessary steps to make certain of the identity of clients or servers before interacting with them remotely. Because .NET Remoting applications require FullTrust permissions to execute, if an unauthorized client were granted access on your server, the client could execute code as if it were fully trusted. Always authenticate your clients and encrypt the communication streams. For more information see Security in Remoting. |
To compile this sample
Type the following commands at the command prompt:
[Visual Basic]
vbc /r:System.Runtime.Remoting.dll /t:library MyRemoteType.vb vbc /r:System.Runtime.Remoting.dll /r:MyRemoteType.dll client.vb vbc /r:System.Runtime.Remoting.dll /r:MyRemoteType.dll server.vb
[C#]
csc /r:System.Runtime.Remoting.dll /t:library MyRemoteType.cs csc /r:System.Runtime.Remoting.dll /r:MyRemoteType.dll client.cs csc /r:System.Runtime.Remoting.dll /r:MyRemoteType.dll server.cs
MyRemoteType
Imports System
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Messaging
Namespace [Shared]
Public Class MyRemoteType
Inherits MarshalByRefObject
Private starttime As DateTime
Public Sub New()
Console.WriteLine("A MyRemoteObject instance has been created.")
starttime = DateTime.Now
End Sub
Protected Overrides Sub Finalize()
Console.WriteLine("MyRemoteObject being collected after " & (New TimeSpan(DateTime.Now.Ticks - starttime.Ticks)).ToString() & " seconds.")
End Sub
Public Function GetServerTime() As DateTime
Console.WriteLine("Time requested by a client.")
' This call overwrites the client's CallContextString.
CallContext.SetData("ServerThreadData", New CallContextString("This is the server side replacement."))
Return DateTime.Now
End Function
End Class
' One method of communicating between client and server is
' to use the CallContext. Calling CallContext.SetData essentially puts the data
' in a Thread Local Store. This means that the information is available
' to that thread or that "logical" thread (across application domains) only.
<Serializable()> _
Public Class CallContextString
Implements ILogicalThreadAffinative
Dim _str As String = ""
Public Sub New(ByVal str As String)
_str = str
Console.WriteLine("CallContextString created.")
End Sub
Public Overrides Function ToString() As String
Return _str
End Function
End Class
End Namespace
using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Messaging;
namespace Shared
{
public class MyRemoteType : MarshalByRefObject
{
private DateTime starttime;
public MyRemoteType()
{
Console.WriteLine("A MyRemoteObject instance has been created.");
starttime = DateTime.Now;
}
~MyRemoteType()
{
Console.WriteLine("MyRemoteObject being collected after " + (new TimeSpan(DateTime.Now.Ticks - starttime.Ticks)).ToString() + " seconds.");
}
public DateTime GetServerTime()
{
Console.WriteLine("Time requested by a client.");
// This call overwrites the client's CallContextString.
CallContext.SetData("ServerThreadData", new CallContextString("This is the server side replacement."));
return DateTime.Now;
}
}
// One method of communicating between client and server is
// to use the CallContext. Calling CallContext.SetData essentially puts the data
// in a Thread Local Store. This means that the information is available
// to that thread or that "logical" thread (across application domains) only.
[Serializable]
public class CallContextString : ILogicalThreadAffinative
{
String _str = "";
public CallContextString(String str)
{
_str = str;
Console.WriteLine("CallContextString created.");
}
public override String ToString()
{
return _str;
}
}
}
Client
[Visual Basic]
Imports System
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Channels
Imports System.Runtime.Remoting.Channels.Http
Imports System.Runtime.Remoting.Contexts
Imports System.Runtime.Remoting.Messaging
Imports [Shared]
Public Class Client
Public Shared Sub Main()
' Register Channel
Dim channel As HttpChannel = New HttpChannel()
ChannelServices.RegisterChannel(channel, False)
' Register MyRemoteObject
RemotingConfiguration.RegisterWellKnownClientType( _
GetType(MyRemoteType), _
"https://localhost:8080/MyRemoteObject")
' Add a CallContextString object to the call context
CallContext.SetData("ServerThreadData", New CallContextString("This is the thread data inserted on the client thread."))
Console.WriteLine("CallContextString prior to the call: " & CallContext.GetData("ServerThreadData").ToString())
Dim service As MyRemoteType = New MyRemoteType()
Console.WriteLine("Server time is: " & service.GetServerTime().ToLongTimeString())
Console.WriteLine("CallContextString after the call: " & CallContext.GetData("ServerThreadData").ToString())
End Sub
End Class
[C#]
using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Http;
using System.Runtime.Remoting.Contexts;
using System.Runtime.Remoting.Messaging;
using Shared;
namespace Client
{
public class Client
{
public static void Main(string[] args)
{
// Register Channel
HttpChannel channel = new HttpChannel();
ChannelServices.RegisterChannel(channel, false);
// Register MyRemoteObject
RemotingConfiguration.RegisterWellKnownClientType(
typeof(MyRemoteType),
"https://localhost:8080/MyRemoteObject");
// Add a CallContextString object to the call context
CallContext.SetData("ServerThreadData", new CallContextString("This is the thread data inserted on the client thread."));
Console.WriteLine("CallContextString prior to the call: " + CallContext.GetData("ServerThreadData").ToString());
MyRemoteType service = new MyRemoteType();
Console.WriteLine("Server time is: " + service.GetServerTime().ToLongTimeString());
Console.WriteLine("CallContextString after the call: " + CallContext.GetData("ServerThreadData").ToString());
}
}
}
Server
[Visual Basic]
Imports System
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Channels
Imports System.Runtime.Remoting.Channels.Http
Imports [Shared]
Public Class Server
Public Shared Sub Main()
' Register channel
Dim channel As HttpChannel = New HttpChannel(8080)
ChannelServices.RegisterChannel(channel, False)
' Register MyRemoteObject
RemotingConfiguration.RegisterWellKnownServiceType( _
GetType(MyRemoteType), _
"MyRemoteObject", _
WellKnownObjectMode.SingleCall)
Console.WriteLine("Press enter to stop this process.")
Console.ReadLine()
End Sub
End Class
[C#]
using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Http;
using Shared;
namespace Server
{
class Server
{
static void Main(string[] args)
{
// Register channel
HttpChannel channel = new HttpChannel(8080);
ChannelServices.RegisterChannel(channel, false);
// Register MyRemoteObject
RemotingConfiguration.RegisterWellKnownServiceType(
typeof(MyRemoteType),
"MyRemoteObject",
WellKnownObjectMode.SingleCall);
Console.WriteLine("Press enter to stop this process.");
Console.ReadLine();
}
}
}