Self-Hosting WCF and System.ServiceModel.FaultException

Question

I have a simple WCF Service Library Project (call this Project W) with a handful of DLLs in directory X. I set the startup directory of W to X, all methods work correctly using WcfServiceHost in Visual Studio 2010.

I want to self-host W, so, I created a console Project (call this Project C), added a reference to W, set the startup directory of W to X, then have essentially the following main lines of code

var host = new ServiceHost(typeof(EvalService));
host.Open();

When I now test the methods in W, I am getting System.ServiceModel.FaultException with {"The specified module could not be found. (Exception from HRESULT: 0x8007007E)"} .

What can this mean? How can I tell what module it is trying to load?

I am fairly new to both C# and WCF, any hint would be apprecited.

Answer 1

You can subscribe to event AppDomain.AssemblyResolve and see in the debugger, which assembly is problematic.

AppDomain currentDomain = AppDomain.CurrentDomain;
currentDomain.AssemblyResolve += OnAssemblyResolve;

...

private static Assembly OnAssemblyResolve(object sender, ResolveEventArgs args)
{
   Console.WriteLine(args.RequestingAssembly); //set breakpoint there
   return null;
}

Answer 2

You need to determine if this error is in the service or the client.

From the error message it seems this is a service side error. You could implement IErrorHandler from http://msdn.microsoft.com/en-us/library/gg281715.aspx .

This will give you access to all errors in your service. You can then log all exceptions and their inner exceptions.

Hope this helps.