c# - 由于 Service 的 'FaultedState'，WCF.ServiceChannel 无法通信

Question

我正在创建一个自托管的 WCF Service .

[ServiceContract(Namespace = "http://Microsoft.ServiceModel.Samples")]
public interface IStateChecker
{
    [OperationContract]
    void SetState(string state);
}

这是我的Service :

public class StateCheckerService : IStateChecker
{
    public void SetState(string state)
    {
        Console.WriteLine($"{DateTime.Now.ToString("dd.MM.yyyy HH:mm:sss")} : {state}");
    }
}

这是我的实现:

//Define baseaddres:
Uri baseAddress = new Uri("http://localhost:8000/ServiceModelSamples/Service");

//create host:
ServiceHost selfHost = new ServiceHost(typeof(StateCheckerService), baseAddress);

try
{
     //Add endpoint to host:
     selfHost.AddServiceEndpoint(typeof(IStateChecker), new WSHttpBinding(), "StateCheckerService");

     //Add metadata exchange:
     ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
     smb.HttpGetEnabled = true;
     selfHost.Description.Behaviors.Add(smb);


     selfHost.Faulted += SelfHost_Faulted;

     //Start service
     selfHost.Open();

     Console.WriteLine("Starting Service...");
     if (selfHost.State == CommunicationState.Opened)
     {
         Console.WriteLine("The service is ready.");
     }

     Console.WriteLine("Press <ENTER> to terminate service.");
     Console.ReadLine();

     //Shutdown service
     selfHost.Close();
}
catch (CommunicationException ce)
{
    Console.WriteLine("An exception occurred: {0}", ce.Message);
    selfHost.Abort();
}

private static void SelfHost_Faulted(object sender, EventArgs e)
{
    ServiceHost host = sender as ServiceHost;
    Console.WriteLine(host?.State);
    Console.WriteLine(e?.ToString());

    host?.Open();
}

现在谈到 客户我得到一个错误。

try
{
    //Works using the ServiceReference (wsdl ... created by VisualStudio):
    using (StateCheckerServiceReference.StateCheckerClient client = new StateCheckerClient())
    {
        client.SetState("Test");
    }

    //Does not work:
    EndpointAddress endpointAddress = new EndpointAddress("http://localhost:8000/ServiceModelSamples/Service");
    using (ChannelFactory<IStateCheckerChannel> factory = new ChannelFactory<IStateCheckerChannel>("WSHttpBinding_IStateChecker", endpointAddress))
    {
        using (IStateCheckerChannel channel = factory.CreateChannel(endpointAddress))
        {
            channel?.SetState("Test");
        }
    }
}
catch (Exception ex)
{
    Console.WriteLine(ex.Message);
}

异常(exception):

The communication object, "System.ServiceModel.Channels.ServiceChannel",
cannot be used for communication because it is in the Faulted state.

I never enter SelfHost_Faulted nor are there any Exceptions on my Service

我这样做是因为我想更改 Endpoint客户端应在运行时连接。

如果我做错了，请告诉我。否则，任何关于我的代码有什么问题的提示都将受到高度赞赏。

Answer 1

这个问题非常微不足道，但被 WCF 基础结构隐藏(标准模式的奇怪实现)。

如果你改变

channel?.SetState("Test");

到

try
{
    channel?.SetState("Test");
}
catch (Exception ex)
{
    Console.WriteLine(ex.Message);
}

您将看到 2 条消息:

There was no endpoint listening at http://localhost:8000/ServiceModelSamples/Service that could accept the message. This is often caused by an incorrect address or SOAP action. See InnerException, if present, for more details.

和

The communication object, System.ServiceModel.Channels.ServiceChannel, cannot be used for communication because it is in the Faulted state.

第一个是由内部 EndpointNotFoundException 捕获的真正异常(类型为 catch ) .

第二个(误导性的)异常是 CommunicationObjectFaultedException 类型。并被 channel.Dispose() 抛出(?!) 在您的 using 末尾调用 block ，因此隐藏了原始的。 WCF 实现根本不遵循 Dispose() 的规则。不应该扔!

话虽如此，问题出在您的客户端端点上。根据服务配置应该是"baseAddress/StateCheckerService"而目前它只是 "baseAddress" .所以只需使用正确的端点地址

var endpointAddress = new EndpointAddress(
    "http://localhost:8000/ServiceModelSamples/Service/StateCheckerService");

问题将得到解决。