How to explicitely set z-order of windows in WPF app?

Question

I need to set windows in my app in certain order programmatically. I tried to set TopMost on all of them to true in the order I need and then to false, hoping it would override the z-index but the behaviour on the screen is not what it supposed to be:

var windows = Application.Current.Windows.Cast<Window>().ToList();

            foreach (var window in windows)
            {
                window.Topmost = true;
            }

            disp.DelayedAction(() =>
            {
                foreach (var window in windows)
                {
                    if (window is CuteButton) continue;

                    window.Topmost = false;
                }
            },
            500);

Answer 1

You can use SetWindowPos Win32 API to order the windows, e.g.:

Window window1;
Window window2;
...
IntPtr firstWindowHandle = ((HwndSource)PresentationSource.FromVisual(window1)).Handle;
IntPtr secondWindowHandle = ((HwndSource)PresentationSource.FromVisual(window2)).Handle;

const int SWP_NOSIZE = 0x0001;
const int SWP_NOMOVE = 0x0002;
SetWindowPos(thisWindowHandle, anotherWindowHandle, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);