Force close all open popups from code

Question

I want to cause all open popups (with StaysOpen == false) to close from code. Basically I want to simulate the user clicking the mouse (which would close the popups) from code.

I don't need to actually simulate the click, I just need the resulting behavior. I've thought about just going through the visual tree looking for popups and closing each one, but that doesn't seem like the cleanest approach.

Thanks in advance for any help or opinions.

Answer 1

Going through the visual tree is the way to do it that isn't dependent in any way on how you've created them in the first place. There may be much cleaner ways of doing it, but they all really depend on your implementation.

For instance, all of the Popups in my application are bound to view model objects that expose some kind of IsOpen property that the Popup binds to. If I needed to implement this functionality in my project, I'd just maintain a collection of these objects (or a generator method) that I could iterate over, and set IsOpen to false on each. This obviously won't work if you aren't building your UI the way I am, though.

Answer 2

A WPF popup actually creates a new window (a Win32 window, not a WPF Window instance). So you can't find it in the Application.Windows collection, but you can probably find it using a Win32 API like EnumChildWindows.

Once you have the handle, you can retrieve the associated HwndSource. I think the RootVisual of the HwndSource is the Popup (didn't check, you might have to look deeper in the visual tree).

So the code should be similar to this (completely untested):

public static class PopupCloser
{
    public static void CloseAllPopups()
    {
        foreach(Window window in Application.Current.Windows)
        {
            CloseAllPopups(window);
        }
    }

    public static void CloseAllPopups(Window window)
    {
        IntPtr handle = new WindowInteropHelper(window).Handle;
        EnumChildWindows(handle, ClosePopup, IntPtr.Zero);
    }

    private static void ClosePopup(IntPtr hwnd, IntPtr lParam)
    {
        HwndSource source = HwndSource.FromHwnd(hwnd);
        if (source != null)
        {
            Popup popup = source.RootVisual as Popup;
            if (popup != null)
            {
                popup.IsOpen = false;
            }
        }
        return true; // to continue enumeration
    }

    private delegate bool EnumWindowsProc(IntPtr hwnd, IntPtr lParam);

    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool EnumChildWindows(IntPtr hwndParent, EnumWindowsProc lpEnumFunc, IntPtr lParam);

}