Error while browing WCF service

Question

2009-11-03 16:36:10,818 [3404] ERROR WebApplication.Global [UserHostAddress: [::1] ApplicationSource [//TestService.svc]] - Application_Error handled Exception: Stack trace for 1 exception(s). Root cause at the top. 1: An item with the same key has already been added. System.ArgumentException inside C:\Windows\assembly\GAC_MSIL\System.ServiceModel\3.0.0.0__b77a5c561934e089\System.ServiceModel.dll at System.ServiceModel.AsyncResult.EndTAsyncResult at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.End(IAsyncResult result) at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.ExecuteSynchronous(HttpApplication context, Boolean flowContext) at System.ServiceModel.Activation.HttpModule.ProcessRequest(Object sender, EventArgs e)

Answer 1

Check your config file. You probably have two entries that have the same name, same contract, or some other duplication.