c# - 尝试在 ASP.NET 网站中托管时出现 WCF 服务异常错误

Question

尝试浏览我的 .svc 文件时出现以下错误。

An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is:
System.NullReferenceException: Object reference not set to an instance of an object.
   at System.ServiceModel.Description.WsdlExporter.CreateWsdlBindingAndPort(ServiceEndpoint endpoint, XmlQualifiedName wsdlServiceQName, Port& wsdlPort, Boolean& newBinding, Boolean& bindingNameWasUniquified)
   at System.ServiceModel.Description.WsdlExporter.ExportEndpoint(ServiceEndpoint endpoint, XmlQualifiedName wsdlServiceQName)
   at System.ServiceModel.Description.WsdlExporter.ExportEndpoints(IEnumerable`1 endpoints, XmlQualifiedName wsdlServiceQName)
   at System.ServiceModel.Description.ServiceMetadataBehavior.MetadataExtensionInitializer.GenerateMetadata()
   at System.ServiceModel.Description.ServiceMetadataExtension.EnsureInitialized()
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.InitializationData.InitializeFrom(ServiceMetadataExtension extension)
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.GetInitData()
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.TryHandleDocumentationRequest(Message httpGetRequest, String[] queries, Message& replyMessage)
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.ProcessHttpRequest(Message httpGetRequest)
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.Get(Message message)
   at SyncInvokeGet(Object , Object[] , Object[] )
   at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
   at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage41(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage31(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage3(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage2(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage1(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)

这是我的 web.config 配置:

  <system.serviceModel>
    <services>
      <service name="WcfServiceLib.WcfService"
               behaviorConfiguration="Default">
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:8080/WebService"/>
          </baseAddresses>
        </host>
        <!-- Service Endpoints -->
        <!-- Unless fully qualified, address is relative to base address supplied above -->
        <endpoint address="" binding="wsHttpBinding" contract="WcfServiceContractLib.IWcfContract"/>
        <endpoint address="web" binding="webHttpBinding" contract="WcfServiceContractLib.IWcfContract"
                  behaviorConfiguration="web"/>
        <endpoint address="webJson" binding="webHttpBinding" contract="WcfServiceContractLib.IWcfContract"
                behaviorConfiguration="webJson"/>
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
      </service>
    </services>
    <behaviors>
      <endpointBehaviors>
        <behavior name="web">
          <webHttp defaultOutgoingResponseFormat="Xml" helpEnabled="true"/>
        </behavior>
        <behavior name="webJson">
          <webHttp defaultOutgoingResponseFormat="Json" helpEnabled="true"/>
        </behavior>
      </endpointBehaviors>
      <serviceBehaviors>
        <behavior name="Default">
          <serviceMetadata httpGetEnabled="true"/>
          <serviceDebug includeExceptionDetailInFaults="true"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <serviceHostingEnvironment aspNetCompatibilityEnabled ="true" />
  </system.serviceModel>

谁有类似情况？

我应该提到，当它托管在我用来运行测试的控制台应用程序中时，一切都很好。

[编辑] 尝试在控制台应用程序中加载服务时发生同样的错误。不显示 WCF 网页，您可以在其中查看 wsdl 信息等...

Answer 1

如果您正在使用 .NET 4.0 并尝试同时托管 SOAP、Xml 和 Json 端点，您将遇到异常。只需注释掉您的 Json 或 Xml 端点，就可以正常工作。

这是我在 Microsoft Connect 上提出的一个已知问题并且 MS 开发团队已将其关闭，因为无法修复。

为了同时支持 Json 和 Xml，如果客户端在请求中仅传递所需的 Accept header ，如“application/xml”或“application/json”，框架会自动处理它并以适当的格式发回响应。