OperationContext.GetCallbackChannel<T> 方法

参考

定义

命名空间:: System.ServiceModel

程序集:: System.ServiceModel.Primitives.dll

程序集:: System.ServiceModel.dll

重要

一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。

获取调用当前操作的客户端实例的通道。

public:
generic <typename T>
 T GetCallbackChannel();

public T GetCallbackChannel<T> ();

member this.GetCallbackChannel : unit -> 'T

Public Function GetCallbackChannel(Of T) () As T

类型参数

T

用于回调到客户端的通道的类型。

T

一个客户端实例的通道，该客户端实例调用 CallbackContract 属性中指定类型的操作。

示例

下面的代码示例使用 Current 属性和 GetCallbackChannel 方法从操作内创建回调用方通道。此示例中的所有操作都是单向操作，使服务和客户端能够独立地进行双向通信。在这种情况下，示例客户端应用程序在退出之前只需要一个返回调用，但另一个客户端（例如Windows 窗体客户端）可以从服务接收任意数量的调用。

using System;
using System.Collections.Generic;
using System.ServiceModel;
using System.Threading;

namespace Microsoft.WCF.Documentation
{
  [ServiceContract(
    Name = "SampleDuplexHello",
    Namespace = "http://microsoft.wcf.documentation",
    CallbackContract = typeof(IHelloCallbackContract),
    SessionMode = SessionMode.Required
  )]
  public interface IDuplexHello
  {
    [OperationContract(IsOneWay = true)]
    void Hello(string greeting);
  }

  public interface IHelloCallbackContract
  {
    [OperationContract(IsOneWay = true)]
    void Reply(string responseToGreeting);
  }

  public class DuplexHello : IDuplexHello
  {
    public DuplexHello()
    {
      Console.WriteLine("Service object created: " + this.GetHashCode().ToString());
    }

    ~DuplexHello()
    {
      Console.WriteLine("Service object destroyed: " + this.GetHashCode().ToString());
    }

    public void Hello(string greeting)
    {
      Console.WriteLine("Caller sent: " + greeting);
      Console.WriteLine("Session ID: " + OperationContext.Current.SessionId);
      Console.WriteLine("Waiting two seconds before returning call.");
      // Put a slight delay to demonstrate asynchronous behavior on client.
      Thread.Sleep(2000);
      IHelloCallbackContract callerProxy
        = OperationContext.Current.GetCallbackChannel<IHelloCallbackContract>();
      string response = "Service object " + this.GetHashCode().ToString() + " received: " + greeting;
      Console.WriteLine("Sending back: " + response);
      callerProxy.Reply(response);
    }
  }
}



Imports System.Collections.Generic
Imports System.ServiceModel
Imports System.Threading

Namespace Microsoft.WCF.Documentation
    <ServiceContract(Name:="SampleDuplexHello", Namespace:="http://microsoft.wcf.documentation", _
                     CallbackContract:=GetType(IHelloCallbackContract), SessionMode:=SessionMode.Required)> _
  Public Interface IDuplexHello
        <OperationContract(IsOneWay:=True)> _
        Sub Hello(ByVal greeting As String)
    End Interface

  Public Interface IHelloCallbackContract
    <OperationContract(IsOneWay := True)> _
    Sub Reply(ByVal responseToGreeting As String)
  End Interface

  Public Class DuplexHello
      Implements IDuplexHello
    Public Sub New()
      Console.WriteLine("Service object created: " & Me.GetHashCode().ToString())
    End Sub

    Protected Overrides Sub Finalize()
      Console.WriteLine("Service object destroyed: " & Me.GetHashCode().ToString())
    End Sub

    Public Sub Hello(ByVal greeting As String) Implements IDuplexHello.Hello
      Console.WriteLine("Caller sent: " & greeting)
      Console.WriteLine("Session ID: " & OperationContext.Current.SessionId)
      Console.WriteLine("Waiting two seconds before returning call.")
      ' Put a slight delay to demonstrate asynchronous behavior on client.
      Thread.Sleep(2000)
            Dim callerProxy = OperationContext.Current.GetCallbackChannel(Of IHelloCallbackContract)()
            Dim response = "Service object " & Me.GetHashCode().ToString() & " received: " & greeting
      Console.WriteLine("Sending back: " & response)
      callerProxy.Reply(response)
    End Sub
  End Class
End Namespace

以下客户端实现 SampleDuplexHelloCallback 接收回调消息。由于在前面的示例中使用 Name 属性，导入的回调协定与服务中的回调协定不同。请注意，客户端不对其是否或何时可能收到回调作出任何假设；服务器回调与客户端的出站调用完全无关。

备注

有关在客户端方案中使用该 OperationContext 类的示例，请参阅 OperationContextScope。

using System;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.Threading;

namespace Microsoft.WCF.Documentation
{
  public class Client : SampleDuplexHelloCallback
  {
    AutoResetEvent waitHandle;

    public Client()
    {
      waitHandle = new AutoResetEvent(false);
    }

    public void Run()
    {
      // Picks up configuration from the config file.
      SampleDuplexHelloClient wcfClient
        = new SampleDuplexHelloClient(new InstanceContext(this));
      try
      {
        Console.ForegroundColor = ConsoleColor.White;
        Console.WriteLine("Enter a greeting to send and press ENTER: ");
        Console.Write(">>> ");
        Console.ForegroundColor = ConsoleColor.Green;
        string greeting = Console.ReadLine();
        Console.ForegroundColor = ConsoleColor.White;
        Console.WriteLine("Called service with: \r\n\t" + greeting);
        wcfClient.Hello(greeting);
        Console.WriteLine("Execution passes service call and moves to the WaitHandle.");
        this.waitHandle.WaitOne();
        Console.ForegroundColor = ConsoleColor.Blue;
        Console.WriteLine("Set was called.");
        Console.Write("Press ");
        Console.ForegroundColor = ConsoleColor.Red;
        Console.Write("ENTER");
        Console.ForegroundColor = ConsoleColor.Blue;
        Console.Write(" to exit...");
        Console.ReadLine();
        wcfClient.Close();
      }
      catch (TimeoutException timeProblem)
      {
        Console.WriteLine("The service operation timed out. " + timeProblem.Message);
        Console.ReadLine();
        wcfClient.Abort();
      }
      catch (CommunicationException commProblem)
      {
        Console.WriteLine("There was a communication problem. " + commProblem.Message);
        Console.ReadLine();
        wcfClient.Abort();
      }
    }

    public static void Main()
    {
      Client client = new Client();
      client.Run();
    }

    public void Reply(string response)
    {
      Console.WriteLine("Received output.");
      Console.WriteLine("\r\n\t" + response);
      this.waitHandle.Set();
    }
  }
}


Imports System.ServiceModel
Imports System.ServiceModel.Channels
Imports System.Threading

Namespace Microsoft.WCF.Documentation
  Public Class Client
      Implements SampleDuplexHelloCallback
    Private waitHandle As AutoResetEvent

    Public Sub New()
      waitHandle = New AutoResetEvent(False)
    End Sub

    Public Sub Run()
      ' Picks up configuration from the config file.
      Dim wcfClient As New SampleDuplexHelloClient(New InstanceContext(Me))
      Try
        Console.ForegroundColor = ConsoleColor.White
        Console.WriteLine("Enter a greeting to send and press ENTER: ")
        Console.Write(">>> ")
        Console.ForegroundColor = ConsoleColor.Green
                Dim greeting = Console.ReadLine()
        Console.ForegroundColor = ConsoleColor.White
        Console.WriteLine("Called service with: " & Constants.vbCrLf & Constants.vbTab & greeting)
        wcfClient.Hello(greeting)
        Console.WriteLine("Execution passes service call and moves to the WaitHandle.")
        Me.waitHandle.WaitOne()
        Console.ForegroundColor = ConsoleColor.Blue
        Console.WriteLine("Set was called.")
        Console.Write("Press ")
        Console.ForegroundColor = ConsoleColor.Red
        Console.Write("ENTER")
        Console.ForegroundColor = ConsoleColor.Blue
        Console.Write(" to exit...")
        Console.ReadLine()
        wcfClient.Close()
      Catch timeProblem As TimeoutException
        Console.WriteLine("The service operation timed out. " & timeProblem.Message)
        Console.ReadLine()
        wcfClient.Abort()
      Catch commProblem As CommunicationException
        Console.WriteLine("There was a communication problem. " & commProblem.Message)
        Console.ReadLine()
        wcfClient.Abort()
      End Try
    End Sub

    Public Shared Sub Main()
      Dim client As New Client()
      client.Run()
    End Sub

    Public Sub Reply(ByVal response As String) Implements SampleDuplexHelloCallback.Reply
      Console.WriteLine("Received output.")
      Console.WriteLine(Constants.vbCrLf & Constants.vbTab & response)
      Me.waitHandle.Set()
    End Sub
  End Class
End Namespace

注解

GetCallbackChannel调用该属性以获取可用于调用服务的客户端实例上的操作的通道。

适用于

通过

OperationContext.GetCallbackChannel<T> 方法

定义

类型参数

返回

示例

注解

适用于

其他资源