Question

I am using reflection to invoke a method in an external assembly. The external class / method is in a WCF data service.

The WCF data service uses information loaded from a custom configuration section in the web.config,

 <configSections>
  <section name="myCustomSection" type="MyWcfService.MyCustomSection, MyWcfService" />
 </configSections>

Loading the configuration variables works fine in the wcf service but not when trying to invoke its methods through reflection via a seperate app. I tried putting the configuration information in the local app.config but I get the same error.

This is the code in the local application:

 Assembly assembly = Assembly.LoadFile
            ("C:\\MyProject\\MyWcfService.dll");

        Type[] t = assembly.GetTypes();

        foreach (var v in t)
        {
            if (v.Name == "MyType")
            {
                var instance = Activator.CreateInstance(v); 
                v.InvokeMember("MyMethod", BindingFlags.InvokeMethod, null, instance, null);
            }
        }  

And this is the code from the external assembly (wcf service) that is producing the error,

   MyCustomSection configSection = ConfigurationManager.GetSection("myCustomSection")
          as MyCustomSection ;

configSection is coming up null – ‘object reference not set to an instance of an object’.

If its looking in the local applications app.config rather than the web.config, adding the same config information locally should work, I would think.

Thanks.

Answer 1

You may need to register with the AppDomain.CurrentDomain.TypeResolve event. This link has an example of how to use it.
http://msdn.microsoft.com/en-us/library/system.appdomain.typeresolve.aspx