Get openned Form

Hello,

I have one form (frmHome) and one page (pgNetwork).

I navigate to the page with a Frame.

How can i Hide button on frmHome from pgNetwork?

I tried: 

var Home = Application.Current.Windows.Cast<Window>().FirstOrDefault(window => window is frmHome) as frmHome;

But VS returns me an error, I already use this code in another program, but I use it inside a UserControl, and now I need in Page.

Regards, ADAE.