WCF, the Service attribute value in the ServiceHost directive could not be found.

Server Error in '/InsusSiteCS' Application.

The type 'Catalog', provided as the Service attribute value in the ServiceHost directive, or provided in the configuration element system.serviceModel/serviceHostingEnvironment/serviceActivations could not be found.

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: The type 'Catalog', provided as the Service attribute value in the ServiceHost directive, or provided in the configuration element system.serviceModel/serviceHostingEnvironment/serviceActivations could not be found. 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: The type 'Catalog', provided as the Service attribute value in the ServiceHost directive, or provided in the configuration element system.serviceModel/serviceHostingEnvironment/serviceActivations could not be found.]
   System.ServiceModel.Activation.ServiceHostFactory.CreateServiceHost(String constructorString, Uri[] baseAddresses) +59638
   System.ServiceModel.HostingManager.CreateService(String normalizedVirtualPath, EventTraceActivity eventTraceActivity) +1434
   System.ServiceModel.HostingManager.ActivateService(ServiceActivationInfo serviceActivationInfo, EventTraceActivity eventTraceActivity) +52
   System.ServiceModel.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath, EventTraceActivity eventTraceActivity) +598

[ServiceActivationException: The service '/InsusSiteCS/WCF/Catalog.svc' cannot be activated due to an exception during compilation.  The exception message is: The type 'Catalog', provided as the Service attribute value in the ServiceHost directive, or provided in the configuration element system.serviceModel/serviceHostingEnvironment/serviceActivations could not be found..]
   System.Runtime.AsyncResult.End(IAsyncResult result) +495736
   System.ServiceModel.Activation.HostedHttpRequestAsyncResult.End(IAsyncResult result) +178
   System.ServiceModel.Activation.HostedHttpRequestAsyncResult.ExecuteSynchronous(HttpApplication context, String routeServiceVirtualPath, Boolean flowContext, Boolean ensureWFService) +229
   System.ServiceModel.Activation.HttpHandler.ProcessRequest(HttpContext context) +24
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +341
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +69

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.18010

Insus.NET有写一个WCF Service ，在测试时，出现如上错误。

经过仔细检查与debug，才发现原来是因为在建立Service时，自己添加上命名空间，而在.svc即没有去添加。

解决问题：