I've got a WPF app that references a WPF controls library. When I try to launch (myWindow.Show()) a window that is inside the control library, I get the following exception:
InvalidDeploymentException Application identity not set.
The bizarre thing is that I'm not doing a click once application, so why is it complaining about this?
Does the window defined in the control library access the System.Deployment namespace? Do you have a stack trace that we could take a look at?
The MSDN doc for InvalidDeploymentException states that this exception indicates that the system "could not read either the deployment or application manifests". Some googling indicates that this exception could be raised when accessing the System.Deployment.Application.ApplicationDeployment.CurrentDeployment property and the application is not a ClickOnce app. I suspect this Window you are using the controls library is accessing this property or something similar in the System.Deployment namespace.
You didn't say whether this was under the VS debugger, but...
I was getting this one today from code that set a control's ImageSource to be a BitmapImage(someURI). The code had been working perfectly, and I was puzzled until I realized that I had for other reasons just told the debugger to break on CLR exceptions. So I unchecked the System.Deployment subcategory of exceptions, and my code once again ran perfectly. Kind of a pain that MS uses the exception system internally to handle cases that I shouldn't have to care about.