ServiceContractAttribute.CallbackContract 屬性

定義

命名空間:

System.ServiceModel

組件:

System.ServiceModel.Primitives.dll

套件:

System.ServiceModel.Primitives v8.0.0

來源:

ServiceContractAttribute.cs

當合約是雙工合約時，取得或設定回呼合約的型別。

public:
 property Type ^ CallbackContract { Type ^ get(); void set(Type ^ value); };

public Type CallbackContract { get; set; }

member this.CallbackContract : Type with get, set

Public Property CallbackContract As Type

屬性值

Type

表示回呼合約的 Type。 預設為 null。

範例

下列程式碼範例顯示指定回呼合約的服務，表示型 IDuplexHello 別的服務必須具有實作 型 IHelloCallbackContract 別服務的對應項。 此外， IHelloCallbackContract 實作單向回呼方法，讓服務呼叫用戶端，而不需要等候回復以支援分散式事件驅動用戶端。

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

備註

在 CallbackContract 屬性中指定介面，這個介面表示雙向 (或雙工) 訊息結算所需的相反合約。 這可讓用戶端應用程式接聽傳入作業呼叫，伺服器端服務應用程式可傳送該呼叫給用戶端，不論用戶端的活動為何。 擁有單向作業的回呼合約，代表從服務端的呼叫，用戶端可處理此呼叫。

注意

回呼合約會忽略 屬性 ServiceContractAttribute 。 若要設定回呼物件的執行時間行為，請使用 System.ServiceModel.CallbackBehaviorAttribute 。