Getting the handle of window in C#

Question

I have the following class declared:

public partial class MainWindow : Window

And I need to get the actual handle of the window once the window has one. How can I do that and where should I put the query function.

What I tried so far was:

IntPtr hwnd = new WindowInteropHelper(this).Handle;

But the handle I get back is 0, which might be because it was planted in OnInitialized - maybe the window is not ready yet at that stage. And, yes - it is connected via WPF, thank you for pointing it out!

Thanks

Answer 1

 [DllImport("user32.dll", EntryPoint = "FindWindowEx")]
        public static extern int FindWindowEx(int hwndParent, int hwndEnfant, int lpClasse, string lpTitre);


int hwnd = FindWindowEx(0, 0, 0, title);//where title is the windowtitle

                //verification of the window
                if (hwnd == 0)
                {
                    throw new Exception("Window not found");
                }

Answer 2

In the OnInitialized method the handle has not yet been created. But you are on the right track. If you put your call in the Loaded event the handle will have been created and it should return the correct handle.

Answer 3

Thank you Stephen for you answer, I'm sure it'll work.

I finally found that it was enough to catch it in the OnActivated function and so the end code looked something like:

public partial class MainWindow : Window
{
    protected override void OnActivated(EventArgs e)
    {
        WindowInteropHelper WIH = new WindowInteropHelper(this);
        IntPtr hwnd = new WindowInteropHelper(this).Handle;
       ...
    }

  ...

}

Thank you guys.

Answer 4

The earliest place you can get the handle is OnSourceInitialized