[WPF]Accessing a public method

Question

Hi

I am working on a WPF application.

In the object Application I create a new object windows :

Code :

toolkit = new Toolkit(this);

Toolkit is defined as public partial class Toolkit : Window
And if i try :

Code :

toolkit.AnyMethod();

The compilator say to me the method is undefined. I can't understand.

I hope you will help me