今天玩WCF时候碰到一个异常，到各大搜索引擎上搜索均没有结果。厉害~！
异常如下：
Server Error in '/' Application.
DistrictWebService must contain either a single ServiceKnownTypeAttribute that refers to a method or a set of ServiceKnownTypeAttributes, each specifying a valid type
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.InvalidOperationException: DistrictWebService must contain either a single ServiceKnownTypeAttribute that refers to a method or a set of ServiceKnownTypeAttributes, each specifying a valid type
Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. |
Stack Trace: [InvalidOperationException: DistrictWebService must contain either a single ServiceKnownTypeAttribute that refers to a method or a set of ServiceKnownTypeAttributes, each specifying a valid type]
System.ServiceModel.Description.TypeLoader.GetKnownTypes(Object[] knownTypeAttributes, ICustomAttributeProvider provider) +11559698
System.ServiceModel.Description.TypeLoader.UpdateOperationsWithInterfaceAttributes(ContractDescription contractDesc, ContractReflectionInfo reflectionInfo) +77
System.ServiceModel.Description.TypeLoader.LoadContractDescriptionHelper(Type contractType, Type serviceType, Object serviceImplementation) +201
System.ServiceModel.Description.ContractDescription.GetContract(Type contractType, Type serviceType) +62
System.ServiceModel.ServiceHost.CreateDescription(IDictionary`2& implementedContracts) +310
System.ServiceModel.ServiceHostBase.InitializeDescription(UriSchemeKeyedCollection baseAddresses) +152
System.ServiceModel.ServiceHost.InitializeDescription(Type serviceType, UriSchemeKeyedCollection baseAddresses) +32
System.ServiceModel.ServiceHost..ctor(Type serviceType, Uri[] baseAddresses) +139
System.ServiceModel.Activation.ServiceHostFactory.CreateServiceHost(Type serviceType, Uri[] baseAddresses) +28
System.ServiceModel.Activation.ServiceHostFactory.CreateServiceHost(String constructorString, Uri[] baseAddresses) +331
System.ServiceModel.HostingManager.CreateService(String normalizedVirtualPath) +11687036
System.ServiceModel.HostingManager.ActivateService(String normalizedVirtualPath) +42
System.ServiceModel.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath) +479
[ServiceActivationException: The service '/DistrictWebService.svc' cannot be activated due to an exception during compilation. The exception message is: DistrictWebService must contain either a single ServiceKnownTypeAttribute that refers to a method or a set of ServiceKnownTypeAttributes, each specifying a valid type.]
System.ServiceModel.AsyncResult.End(IAsyncResult result) +11592858
System.ServiceModel.Activation.HostedHttpRequestAsyncResult.End(IAsyncResult result) +194
System.ServiceModel.Activation.HostedHttpRequestAsyncResult.ExecuteSynchronous(HttpApplication context, Boolean flowContext) +176
System.ServiceModel.Activation.HttpModule.ProcessRequest(Object sender, EventArgs e) +275
System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +68
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75
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Version Information: Microsoft .NET Framework Version:2.0.50727.4927; ASP.NET Version:2.0.50727.4927
