wcf中的使用全雙工通信

wcf中的契約通信默認是請求恢復的方式，當客戶端發出請求后，一直到服務端回復時，才可以繼續執行下面的代碼。

除了使用請求應答方式的通信外，還可以使用全雙工。下面給出例子：

1.添加一個wcf類庫

2.在服務契約添加如下一個片段

[ServiceContract(Namespace = "http://Microsoft.ServiceModel.Samples", SessionMode = SessionMode.Required,?
??????? CallbackContract = typeof(ICalculatorDuplexCallback))]

public interface ICalculatorDuplex?
?? {?
?????? [OperationContract(IsOneWay = true)]?
?????? void Clear();?
?????? [OperationContract(IsOneWay = true)]?
?????? void AddTo(double n);?
?????? [OperationContract(IsOneWay = true)]?
?????? void SubtractFrom(double n);?
?????? [OperationContract(IsOneWay = true)]?
?????? void MultiplyBy(double n);?
?????? [OperationContract(IsOneWay = true)]?
?????? void DivideBy(double n);?
?? }

其中ICalculatorDuplexCallback為實現全雙工客戶端的接口

3.定義ICalculatorDuplexCallback接口。該接口目的主要是回調客戶端的方法。和服務端無關，所以讓該接口的方法設置為單向的

public interface ICalculatorDuplexCallback?
{?
??? [OperationContract(IsOneWay = true)]?
??? void Equals(double result);?
??? [OperationContract(IsOneWay = true)]?
??? void Equation(string eqn);?
}?
4.由于回話是必須的，那么在契約實現的時候也要加上一個特性

??[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession)]

public class Service1 : IService1?
?? {?
?????? double result;?
?????? string equation;?
?????? ICalculatorDuplexCallback callback = null;

?????? public Service1()?
?????? {?
?????????? result = 0.0D;?
?????????? equation = result.ToString();?
?????????? callback = OperationContext.Current.GetCallbackChannel<ICalculatorDuplexCallback>();?
?????? }

?????? public void Clear()?
?????? {?
?????????? callback.Equation(equation + " = " + result.ToString());?
?????????? result = 0.0D;?
?????????? equation = result.ToString();?
?????? }

?????? public void AddTo(double n)?
?????? {?
?????????? result += n;?
?????????? equation += " + " + n.ToString();?
?????????? callback.Equals(result);?
?????? }

?????? public void SubtractFrom(double n)?
?????? {?
?????????? result -= n;?
?????????? equation += " - " + n.ToString();?
?????????? callback.Equals(result);?
?????? }

?????? public void MultiplyBy(double n)?
?????? {?
?????????? result *= n;?
?????????? equation += " * " + n.ToString();?
?????????? callback.Equals(result);?
?????? }

?????? public void DivideBy(double n)?
?????? {?
?????????? result /= n;?
?????????? equation += " / " + n.ToString();?
?????????? callback.Equals(result);?
?????? }?
}

5.接著在項目中添加一個控制臺程序，添加服務。服務會報異常

System.InvalidOperationException: 協定需要會話，但是綁定“BasicHttpBinding”不支持它或者因配置不正確而無法支持它。?
?? 在 System.ServiceModel.Description.DispatcherBuilder.BuildChannelListener(StuffPerListenUriInfo stuff, ServiceHostBase serviceHost, Uri listenUri, ListenUriMode listenUriMode, Boolean supportContextSession, IChannelListener& result)?
?? 在 System.ServiceModel.Description.DispatcherBuilder.InitializeServiceHost(ServiceDescription description, ServiceHostBase serviceHost)?
?? 在 System.ServiceModel.ServiceHostBase.InitializeRuntime()?
?? 在 System.ServiceModel.ServiceHostBase.OnOpen(TimeSpan timeout)?
?? 在 System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)?
?? 在 Microsoft.Tools.SvcHost.ServiceHostHelper.OpenService(ServiceInfo info)

需要把服務端配置文件中改一下：

<system.serviceModel>
<services>
<service name="WcfService1.Service1" behaviorConfiguration="WcfService1.Service1Behavior">

<!-- Service Endpoints -->
<!-- 除非完全限定，否則地址將與上面提供的基址相關 -->
<endpoint address="" binding="wsDualHttpBinding" contract="WcfService1.IService1">
<!--
部署時，應刪除或替換下列標識元素，以反映
用來運行所部署服務的標識。刪除之后，WCF 將
自動推斷相應標識。
-->
<identity>
<dns value="localhost"/>
</identity>
</endpoint>
<!-- Metadata Endpoints -->
<!-- 元數據交換終結點供相應的服務用于向客戶端做自我介紹。 -->
<!-- 此終結點不使用安全綁定，應在部署前確保其安全或將其刪除-->
<endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
</service>
</services>
<behaviors>
<serviceBehaviors>
<behavior name="WcfService1.Service1Behavior">
<!-- 為避免泄漏元數據信息，
請在部署前將以下值設置為 false -->
<serviceMetadata httpGetEnabled="False" httpsGetEnabled="False"/>
<!-- 要接收故障異常詳細信息以進行調試，
請將以下值設置為 true。在部署前設置為 false
以避免泄漏異常信息-->
<serviceDebug includeExceptionDetailInFaults="True" />
</behavior>
</serviceBehaviors>
</behaviors>
</system.serviceModel>

6.在控制臺端，添加服務引用，實現服務定義的ICalculatorDuplexCallback接口（該接口自動生成的對應到服務引用中的IService1Callback）

public class CallbackHandler : IService1Callback?
? {?
????? public void Equals(double result)?
????? {?
????????? Console.WriteLine("Result({0})", result);?
????? }

????? public void Equation(string eqn)?
????? {?
????????? Console.WriteLine("Equation({0})", eqn);?
????? }?
? }

7.在main函數中，去調用服務

?????????? InstanceContext instanceContext = new InstanceContext(new CallbackHandler());

??????????? // Create a client?
??????????? ServiceReference1.Service1Client client = new ServiceReference1.Service1Client(instanceContext);

??????????? Console.WriteLine("Press <ENTER> to terminate client once the output is displayed.");?
??????????? Console.WriteLine();

??????????? // Call the AddTo service operation.?
??????????? double value = 100.00D;?
??????????? client.AddTo(value);

??????????? // Call the SubtractFrom service operation.?
??????????? value = 50.00D;?
??????????? client.SubtractFrom(value);

??????????? // Call the MultiplyBy service operation.?
??????????? value = 17.65D;?
??????????? client.MultiplyBy(value);

??????????? // Call the DivideBy service operation.?
??????????? value = 2.00D;?
??????????? client.DivideBy(value);

??????????? // Complete equation?
??????????? client.Clear();

??????????? Console.ReadLine();

??????????? //Closing the client gracefully closes the connection and cleans up resources?
??????????? client.Close();

8.運行結果

轉載于:https://www.cnblogs.com/fuchongjundream/p/3833248.html

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