遠端處理範例：CallContext

發行項
08/20/2007

這個範例使用 CallContext 類別和 ILogicalThreadAffinative 介面，在跨應用程式定義域界限或內容界限呼叫的兩端執行緒間傳遞資料。

這個應用程式可在單一電腦上或跨網路執行。如果想要透過網路執行這個應用程式，則必須將用戶端組態中的 "localhost" 取代為遠端電腦的名稱。

雖然這個範例不會編譯 ServiceClass.vb，但是在此處會包含這個檔案，以示範 ILogicalThreadAffinative。

警告

.NET 遠端處理預設不會執行驗證或加密。因此，建議在與用戶端或伺服器進行遠端互動之前，先採取所有必要步驟以確定這些用戶端或伺服器的識別。因為 .NET 遠端處理應用程式需要 FullTrust 權限才能執行，所以如果將伺服器的存取權授與未授權用戶端，則該用戶端可如受到完全信任般地執行程式碼。請一律驗證您的端點並加密通訊資料流，方法是在網際網路資訊服務 (IIS) 中裝載遠端處理的型別，或建置自訂通道接收組，以完成這項作業。

編譯這個範例

在命令提示字元中輸入下列命令：

csc /r:System.Runtime.Remoting.dll /t:library ServiceClass.cs

csc /r:System.Runtime.Remoting.dll /r:ServiceClass.dll client.cs

vbc /r:System.Runtime.Remoting.dll /r:ServiceClass.dll clientvb.vb

csc /r:System.Runtime.Remoting.dll /r:ServiceClass.dll server.cs

ServiceClass.cs

using System;
using System.Collections;
using System.Diagnostics;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Messaging;
using System.Runtime.Remoting.Contexts;
using System.Runtime.Remoting.Channels;

public class ContextBoundType : ContextBoundObject{

    private DateTime starttime;

   public ContextBoundType(){
      Console.WriteLine("A ContextBoundType instance has been created.");
       starttime = DateTime.Now;
   }

    ~ContextBoundType(){
        Console.WriteLine("ContextBoundType 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 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;
    }
}

ServiceClass.vb

包含這個檔案僅供參考。

Imports System
Imports System.Collections
Imports System.Diagnostics
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Messaging
Imports System.Runtime.Remoting.Contexts
Imports System.Runtime.Remoting.Channels

Public Class ContextBoundType
   Inherits ContextBoundObject

   Private StartTime As DateTime

   Public Sub New()
      Console.WriteLine("A ContextBoundType instance has been created. (Constructor)")
      StartTime = DateTime.Now
   End Sub  'New

   Protected Overrides Sub Finalize()
      Console.WriteLine("ContextBoundType being collected after " & (New TimeSpan(DateTime.Now.Ticks - starttime.Ticks)).ToString() & " seconds.")
      MyBase.Finalize()
   End Sub   'Finalize

   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  'GetServerTime

End Class 'ContextBoundType


'  One of the methods of communicating between client and server is 
'  to use the CallContext. Calling CallContext 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

   Private _str As String = ""

   Public Sub New(ByVal Contents As String)
      _str = Contents
      Console.WriteLine("CallContextString created with string ""{0}""", Contents)
   End Sub  'New

   Public Overrides Function ToString() As String
      Return _str
   End Function  'ToString

End Class 'CallContextString

ClientVB.vb

Imports System
Imports System.Reflection
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Channels
Imports System.Runtime.Remoting.Channels.Tcp
Imports System.Runtime.Remoting.Channels.Http
Imports System.Runtime.Remoting.Contexts
Imports System.Runtime.Remoting.Messaging

Public Class ClientProcess
   <MTAThread()> _
   Public Shared Sub Main()

      Dim Channel As New HttpChannel()
      ChannelServices.RegisterChannel(Channel)

      Dim RemoteType As New WellKnownClientTypeEntry(GetType(ContextBoundType), "http://localhost:8080/TcpCBOService")
      RemotingConfiguration.RegisterWellKnownClientType(RemoteType)

      ' This sets a CallContextDataSlot on this thread. CallContextString      
      ' will convert the ThreadLocalDataStore into a property on the 
      ' message, which will then be merged into the ThreadLocalDataStore 
      ' on the server. This is a nice way to pass information from client 
      ' to server threads and back again. NOTE: This data store has 
      ' logical thread scope. If an application domain has more than one 
      ' thread making calls, each thread will have its own logical 
      ' CallContext, and the server thread will keep each separate.
      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 New ContextBoundType()

      Console.WriteLine("Server time is: " & service.GetServerTime().ToLongTimeString())

      Console.WriteLine("CallContextString after the call: " & CallContext.GetData("ServerThreadData").ToString())

   End Sub   'Main

End Class   'ClientProcess

Client.cs

using System;
using System.Reflection;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
using System.Runtime.Remoting.Channels.Http;
using System.Runtime.Remoting.Contexts;
using System.Runtime.Remoting.Messaging;

public class ClientProcess{

   public static void Main(string[] Args){

        HttpChannel channel = new HttpChannel();
        ChannelServices.RegisterChannel(channel);

        WellKnownClientTypeEntry remotetype = new WellKnownClientTypeEntry(typeof(ContextBoundType),"http://localhost:8080/TcpCBOService");
       RemotingConfiguration.RegisterWellKnownClientType(remotetype);

        // This sets a CallContextDataSlot on this thread. 
        // CallContextString will convert the ThreadLocalDataStore into 
        // a property on the message, which will then be merged into the 
        // ThreadLocalDataStore on the server. This is a nice way to pass 
        // information from client to server threads and back again. 
        // NOTE: This data store has logical thread scope. If an 
        // application domain has more than one thread making calls, 
        // each thread will have its own logical CallContext, and the 
        // server thread will keep each separate.
        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());

        ContextBoundType service = new ContextBoundType(); 

        Console.WriteLine("Server time is: " + service.GetServerTime().ToLongTimeString());

        Console.WriteLine("CallContextString after the call: " + CallContext.GetData("ServerThreadData").ToString());

   }
}

Server.cs

using System;
using System.Diagnostics;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
using System.Runtime.Remoting.Channels.Http;
using System.Runtime.Remoting.Contexts;
using System.Runtime.Remoting.Messaging;
using System.Threading;

public class ServerProcess{

   public static void Main(string[] Args){

      HttpChannel channel = new HttpChannel(8080);

      ChannelServices.RegisterChannel(channel);
        
      WellKnownServiceTypeEntry WKSTE = new WellKnownServiceTypeEntry(typeof(ContextBoundType),"TcpCBOService", WellKnownObjectMode.SingleCall);
      RemotingConfiguration.RegisterWellKnownServiceType(WKSTE);

      Console.WriteLine("Press enter to stop this process.");
      Console.ReadLine();

   }

}

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