Question

I have web services written on WCF. I use request/response pattern and don’t use FaultException. I return an error code in response contract as string. I need to expose error codes for clients in order to clients can handle exceptions. 

For example:

Var r = client.DoSomething();
Switch (r.ErrorCode)
{
   Case ERROR_CODES.SomeCode:
   //TODO:
}

Clients are WS-*, not only .Net.

UPDATE:

Sorry, my English is elementary. I’ve tried to explain in a different way.
When I use class File, I know that this class can throws some exceptions, for example, FileNotFoundException or DirectoryNotFoundException. If I create a File service How can I tell client that my service can returns “FileNotFound” or other error codes?

Answer 1

We generally try and use FaultContracts.

When we cannot we use a Response object that inherits from ResponseBase. ResponseBase has 2 properties, StatusCode and StatusMessage.

In your case ErrorCode, just add this property to your data contract.