WCF 学习笔记之双工实现

 

其中 Client 和Service为控制台程序 Service.Interface为类库

首先了解契约Interface两个接口

using System.ServiceModel;
using System.ServiceModel.Channels;
namespace Artech.WcfServices.Service.Interface
{
    [ServiceContract(Namespace = "http://www.artech.com/", CallbackContract = typeof(ICalculatorCallback))]
    public interface ICalculator
    {
        [OperationContract(IsOneWay = true)]
        void Add(double x, double y);
    }
}

这边要注意两个地方：一个是明确回调查的接口，和设置让它为单向模式[CallbackContract = typeof(ICalculatorCallback)]；IsOneWay = true

回调接口的代码如下：     

using System.ServiceModel;
namespace Artech.WcfServices.Service.Interface
{
    public interface ICalculatorCallback
    {
        [OperationContract(IsOneWay = true)]
        void DisplayResult(double result, double x, double y);
    }
}

此处也有两个地方要注意：回调契约没有定义[ServiceContact]的特性是因为在指定CallbackContract属性时就隐含对应的接口是个服务契约；此外同样也要设置为单向IsOneWay = true

接下来是服务实现层的代码：

using System.ServiceModel;
using Artech.WcfServices.Service.Interface;
using System.Threading;
namespace Artech.WcfServices.Service
{
    public class CalculatorService : ICalculator
    {
        public void Add(double x, double y)
        {
            double result = x + y;
            ICalculatorCallback callback = OperationContext.Current.GetCallbackChannel<ICalculatorCallback>();
            callback.DisplayResult(result, x, y);
        }
    }
}

相对应的App.config配置

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.serviceModel>    
    <behaviors>
      <serviceBehaviors>
        <behavior name="exposeExceptionDetail">
          <serviceDebug includeExceptionDetailInFaults="true"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <services>
      <service name="Artech.WcfServices.Service.CalculatorService"
               behaviorConfiguration="exposeExceptionDetail">
        <endpoint address="net.tcp://127.0.0.1:3721/calculatorservice"
                  binding="netTcpBinding"
                  contract="Artech.WcfServices.Service.Interface.ICalculator"/>
      </service>
    </services>
  </system.serviceModel>
</configuration>

关于绑定类型的选择必须明确是支持双向通信的类型才可以；比如NetTcpBinding,WSDualHttpBinding ;这边应该注意在采用WSDualHttpBinding时要把可靠会话打开，因为它是通过可靠会话维护两个HTTP通道之间的匹配；
例如：<reliableSession enabled="true"/>

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.serviceModel>
    <bindings>
      <netTcpBinding>
        <binding name="reliableSessionBinding">
          <reliableSession enabled="true"/>
        </binding>
      </netTcpBinding>
    </bindings>
    <behaviors>
      <serviceBehaviors>
        <behavior name="exposeExceptionDetail">
          <serviceDebug includeExceptionDetailInFaults="true"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <services>
      <service name="Artech.WcfServices.Service.CalculatorService"
               behaviorConfiguration="exposeExceptionDetail">
        <endpoint address="net.tcp://127.0.0.1:3721/calculatorservice"
                  binding="netTcpBinding"
                  bindingConfiguration="reliableSessionBinding"
                  contract="Artech.WcfServices.Service.Interface.ICalculator"/>
      </service>
    </services>
  </system.serviceModel>
</configuration>

服务层还有一个代码就是宿主打开

using System.ServiceModel;
using Artech.WcfServices.Service.Interface;
using System.Threading;
using System.ServiceModel.Description;
namespace Artech.WcfServices.Service
{
    class Program
    {
        static void Main(string[] args)
        {
            using (ServiceHost host = new ServiceHost(typeof(CalculatorService)))
            {
                host.Open();
                Console.Read();
            }
        }
    }
}

接下来是客户端的实现，要实现回调接口的

using Artech.WcfServices.Service.Interface;
namespace Artech.WcfServices.Client
{
    public class CalculatorCallbackService : ICalculatorCallback
    {
        public void DisplayResult(double result, double x, double y)
        {
            Console.WriteLine("x + y = {2} when x = {0}  and y = {1}", x, y, result);
        }
    }
}

以及相对应的配置文件内容：

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.serviceModel>    
    <client>
      <endpoint name ="calculatorservice"
                address="net.tcp://127.0.0.1:3721/calculatorservice"
                binding="netTcpBinding"
                contract="Artech.WcfServices.Service.Interface.ICalculator"/>
    </client>
  </system.serviceModel>
</configuration>

以及运行的代码：

using System.ServiceModel;
using Artech.WcfServices.Service.Interface;
using System.ServiceModel.Channels;
using System.Threading;
namespace Artech.WcfServices.Client
{
    class Program
    {
        static void Main(string[] args)
        {
            InstanceContext callback = new InstanceContext(new CalculatorCallbackService());
            using (DuplexChannelFactory<ICalculator> channelFactory = new DuplexChannelFactory<ICalculator>(callback, "calculatorservice"))
            {
                ICalculator calculator = channelFactory.CreateChannel();
                calculator.Add(1, 2);
            }
            Console.Read();
        }
    }
}

针对TCP协议要把服务器的相对应服务打开；或者可能会报错；

错误一：TransportManager 无法使用 NetTcpPortSharing 服务侦听提供的 URI: 无法启动服务，因为该服务已禁用。管理员运行 "sc.exe config NetTcpPortSharing start= demand" 可以将其启用 [NetTcpPortSharing 服务没有启动]

错误二：TransportManager 无法使用 NetTcpPortSharing 服务侦听提供的 URI: 服务侦听失败 [端口被占用，换个端口]