Trying to find out why my WCF service is not working

Question

Over a year ago I had been working on a WCF service, which I wrote using VS 2008. It runs under a Windows service, which I also wrote. It’s been running there ever since. And unfortunately, other projects/priorities have come up, preventing me from continuing with that project, until now.

Now I’m trying to get back to it. However, this go around I’m trying to find out if I can use VS 2010 and .NET 4, instead of .NET 3.5. I’ve brought up the command prompt, to run SvcUtil, to get the wsdl information, which I’ll put into the config file for the new WPF app I’m trying to get started writing. Only thing is, I keep getting an error, saying that I can’t reach the server, etc.

So, I copied the .exe.config file from the server to my machine, where I could edit it with SvcConfigEditor. I’ve made those changes, put it back onto the server, and got an error while trying to run SvcUtil, but worse than that I didn’t see the .svclog files I expected to see. So I got into the server’s Services app. I found the Windows service I wrote a year ago; saw that it was running, and stopped and started it again.

Now I’ve got a different problem. My Windows service starts, but then stops immediately. I get this message saying that the service had started and then stopped, and saying that sometimes that happens with different sorts of services, like Performance Logs and Alerts services. I’ve checked the event log on the server, and then only thing there related to this Windows service is that it entered the start state and then entered the stopped state.

Ah, after attempting to start it 4 times, it finally gave me an error in the event log! (Why didn’t it do that in the first place? And who says that trying to do the same thing over and over again, and expecting different results is a sign of insanity, when clearly the first 3 times it didn’t register anything in the event log, but on the 4th try it did.)

Here’s the error:

Event Type: Error Event Source: Service1 Event Category: None Event ID: 0 Date: 5/4/2011 Time: 10:14:46 AM User: N/A Computer: HELIOS Description: Service cannot be started. System.TypeInitializationException: The type initializer for 'System.ServiceModel.DiagnosticUtility' threw an exception. --->System.Configuration.ConfigurationErrorsException: Couldn't find type for class System.Diagnostics.XmlWriterTraceListener, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089. at System.Diagnostics.TraceUtils.GetRuntimeObject(String className, Type baseType, String initializeData)

and here’s the new section of code put into the .config file by SvcConfigEditor:

<sharedListeners>
<add initializeData="C:\Program Files\ASIWindowsService\ASIWindowsService_tracelog.svclog"
type="System.Diagnostics.XmlWriterTraceListener, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
name="ServiceModelTraceListener" traceOutputOptions="Timestamp">
<filter type="" />
</add>
<add initializeData="C:\Program Files\ASIWindowsService\ASIWindowsService_messages.svclog"
type="System.Diagnostics.XmlWriterTraceListener, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
name="ServiceModelMessageLoggingListener" traceOutputOptions="Timestamp">
<filter type="" />
</add>
</sharedListeners>

Answer 1

This question was answered in the comments but there is a gotcha that I've seen in Visual Studio 2010 that could result in a similar situation.

Even if the target framework is set to version 3.x for a WCF project, using the 2010 SvcConfigEditor will automatically insert "System.Diagnostics.XmlWriterTraceListener, System, Version=4.0.0.0..." although it should be inserting "System.Diagnostics.XmlWriterTraceListener, System, Version=2.0.0.0..." This will bite you when deploying the altered web.config to an IIS hosted service where the AppPool is not configured to use the .NET 4.0 framework. The fix is simply edit the web.config back to "Version=2.0.0.0".