Wpf window title bar mouse activity

Question

I'm trying to get event on window title bar (for a standard wpf window).

A simple mouse down event (no matter the button) would be enough. The idea is that i want to perform action on a custom control (which contain a textbox) when user click outside the control.

For now i'm adding two events handler to the control to help that: UIElement.IsKeyboardFocusWithinChanged and Window.PreviewMouseDown. It works almost perfectly with this two event, except when user click on the window title bar as none of these two events are being fired...

Any ideas ? Thanks

Answer 1

You can use the following code to check if a window border has been clicked:

private const int WM_NCLBUTTONDOWN = 0x00a1;

// added after window loaded
HwndSource source = HwndSource.FromHwnd(new WindowInteropHelper(this).Handle);
source.AddHook(new HwndSourceHook(WndProc));

private static IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
    switch (msg)
    {
        case WM_NCLBUTTONDOWN:
            // your action
            break;
    }

    return IntPtr.Zero;
}