How do I know if a WPF window is opened

Question

In a WPF window, how do I know if it is opened?

My goal to open only 1 instance of the window at the time.

So, my pseudo code in the parent window is:

<

Answer 1

If you need to activate the window if it is found, you can use the code below:

//activate a window found
//T = Window

 Window wnd = Application.Current.Windows.OfType().Where(w => w.Name.Equals(nome)).FirstOrDefault();
 wnd.Activate();