WCF Server/Client connection handling

Question

Hi everyone,

I'm having some problems with my WCF server and client connections.

If I use my service and client normally, meaning my client connects and disconnects thru normal operations (myclient.Close()) everything works fine. But in the instance that I have the server running and I use the visual studio "Stop" button to exit my client application, my server and client communications seems to mess up and the server doesn't clean up the connection correctly and any new connections from my client are very unstable and only certain function calls work until one function will throw an exception of:

System.ServiceModel.CommunicationException: An error occurred while receiving the HTTP response to http://localhost:8080/Design_Time_Addresses/Service_Beta1/Service. This could be due to the service endpoint binding not using the HTTP protocol. This could also be due to an HTTP request context being aborted by the server (possibly due to the service shutting down). See server logs for more details. ---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive.

And many other exceptions after that, and I'll spare you from reading those.

If I shutdown the server and client and restart both, all my calls work fine until I do the drastic "Stop" in visual studio. How can I force the server to clean up improperly closed connections? I know in production the "Stop" button is gone and in theory there shouldn't be problems, but I don't want to have server connection problems from crashes of clients or bad disconnects. Because inevitably there will be those cases. It's best to fix this now before you have 20+ clients trying to connect and getting exceptions.

Thanks

Answer 1

Can you provide more details about your service behaviors -- concurrency mode and instance mode -- and operation contracts/fault contracts? Are the calls that "succeed" one-way calls? And the one that fails a two-way call? Do you have any client callbacks involved?

Answer 2

Sorry for taking such a long time to post a reply. My problem is I was passing back a datatable to the client but wasn't giving the table a name on creation. See below.

Dim dt As New DataTable() 'Passing just a blank un-named table to client gave errors.
Dim dt As New DataTable("Table") 'Naming the table like so passes just fine.