Turns out, after a little more exploration, that the Template property will be null unless the control has been rendered on the screen.

It appears that when you construct a WPF control in code, its Template property isn't initialized. For example: ListBox listBox = new ListBox(); If you instantiate a ListBox like this, then walk the object hierarchy down to the Template property of the Control base class, you'll see that it hasn't been initilaized.

The error is obviously thrown by the line: XamlWriter.Save(template, writer); since template is null.

I ran your first version which looks promising, only the line: ControlTemplate template = control.Template; Always assigns a null value to the template variable. The error message is typically: << Error generating template: Parameter name: obj>> Are you seeing the same thing? Thanks for your reply, Bob

Does anyone know where to find the complete default control template xaml listings for the WPF controls? Thanks. Bob