c# - 使用 WCF 服务拒绝连接

Question

我使用 WCF 创建了一个服务但无法连接到它，我不断收到以下错误:

Could not connect to net.tcp://localhost:5555/ControlChannel. The connection attempt lasted for a time span of 00:00:02.0139182. TCP error code 10061: No connection could be made because the target machine actively refused it 127.0.0.1:5555.

这是代码:

契约(Contract):

[ServiceContract(CallbackContract = typeof(IControlChannelCallback))]
public interface IControlChannel
{
    [OperationContract]
    void Join();
}

回调合约:

public interface IControlChannelCallback
{
    [OperationContract(IsOneWay = true)]
    void ShowMessage(string message);
}

服务:

[ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Single, IncludeExceptionDetailInFaults = true)]
public sealed class ControlChannel : IControlChannel
{
    public static readonly IList<IControlChannelCallback> Callbacks = new List<IControlChannelCallback>(); 

    public void Join()
    {
        var client = OperationContext.Current.GetCallbackChannel<IControlChannelCallback>();

        if (!Callbacks.Contains(client))
            Callbacks.Add(client);

        client.ShowMessage("This message came from the server");
    }
}

服务器:

public MainForm()
{
     InitializeComponent();

     using (var host = new ServiceHost(typeof(ControlChannel)))
     {
          host.Open();
     }
 }

客户:

public MainForm()
{
     InitializeComponent();

     var callback = new ControlChannelCallbackClient();

     using (var factory = new DuplexChannelFactory<IControlChannel>(callback, "Client"))
     {
          var proxy = factory.CreateChannel();

          proxy.Join();
     }
 }

App.config 客户端:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    </startup>
    <system.serviceModel>
      <client>
        <endpoint name="Client"
                  contract="Service.Contracts.Interfaces.IControlChannel"
                  binding="netTcpBinding"
                  address="net.tcp://localhost:5555/ControlChannel" />
      </client>
    </system.serviceModel>
</configuration>

App.config 服务器

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    </startup>
    <system.serviceModel>
      <services>
        <service name="Service.Contracts.Objects.ControlChannel">
          <endpoint contract="Service.Contracts.Interfaces.IControlChannel"
                    binding="netTcpBinding"
                    address="net.tcp://localhost:5555/ControlChannel" >
          </endpoint>
        </service>
      </services>
    </system.serviceModel>
</configuration>

我做错了什么？是代码问题还是我应该开始在其他地方寻找问题？

Answer 1

只是一种预感，但我怀疑没有任何监听，因为即使托管您的服务的应用程序可能仍在运行，但服务主机却没有。在你的构造函数中:

public MainForm()
{
    InitializeComponent();

    using (var host = new ServiceHost(typeof(ControlChannel)))
    {
        host.Open();
    }
}

您的 ServiceHost 位于 using block 中 - 一旦 using block 退出(就在构造函数完成之前)，ServiceHost 将是关闭并处置。

将您的代码更改为:

public MainForm()
{
    InitializeComponent();

    var host = new ServiceHost(typeof(ControlChannel))
    host.Open();
}

您可以挂接到应用程序关闭事件以在程序运行结束时关闭 ServiceHost。

我还建议将 host.Open() 包装在 try-catch block 中，以防在尝试打开它时出现问题。