On the issue of modal windows

[BlameTwo]

5月I ask how to implement a modal window similar to the Windows ShowDialog() on Windows App SDK? I have seen the relevant API, but I am unable to set a Control to a new modal window. When can I do this?

[BlameTwo]

I know that ContentDialogs can solve related problems, but in some cases, such as browser login or better blocking user operations, this problem is inevitable

[castorix]

This test works for me with Windows App SDK 1.42, but maybe there is a simpler method with latest versions...

{
    Button btn1;
    Grid grid1 = new Grid()
    {
        Background = new SolidColorBrush(Microsoft.UI.Colors.Blue),
        HorizontalAlignment = HorizontalAlignment.Stretch,
        VerticalAlignment = VerticalAlignment.Stretch,
        Children =
    {
        (btn1 = new Button()
        {
            HorizontalAlignment = HorizontalAlignment.Center,
            VerticalAlignment = VerticalAlignment.Center,
            Content = "Click" }
        ),
    }
    };

    btn1.Click += (sender, e) =>
    {
        Console.Beep(5000, 10);
    };

    Window wnd1 = new Window()
    {
        Content = grid1
    };
    IntPtr hWnd1 = WinRT.Interop.WindowNative.GetWindowHandle(wnd1);
    Microsoft.UI.WindowId windowId1 = Microsoft.UI.Win32Interop.GetWindowIdFromWindow(hWnd1);
    Microsoft.UI.Windowing.AppWindow appWindow1 = Microsoft.UI.Windowing.AppWindow.GetFromWindowId(windowId1);
    appWindow1.Resize(new Windows.Graphics.SizeInt32(400, 300));
    appWindow1.Move(new Windows.Graphics.PointInt32(600, 400));
    Microsoft.UI.Windowing.OverlappedPresenter presenter = appWindow1.Presenter as Microsoft.UI.Windowing.OverlappedPresenter;

    IntPtr hWnd = WinRT.Interop.WindowNative.GetWindowHandle(this);
    // e = "Paramètre incorrect.\r\n\r\nThe window should have an owner when IsModal=true."
    SetWindowLong(hWnd1, GWL_HWNDPARENT, hWnd);
    presenter.IsModal = true;

    wnd1.Closed += (sender, e) =>
    {
        // Otherwise the focus on main window is lost...
        EnableWindow(hWnd, true);
    };

    wnd1.Activate();
    appWindow1.Show();

    return;
}

with :

    [DllImport("User32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
    public static extern bool EnableWindow(IntPtr hWnd, bool bEnable);

    public const int GWL_STYLE = (-16);
    public const int GWL_EXSTYLE = (-20);
    public const int GWL_HWNDPARENT = (-8);
    public static IntPtr SetWindowLong(IntPtr hWnd, int nIndex, IntPtr dwNewLong)
    {
        if (IntPtr.Size == 4)
        {
            return SetWindowLongPtr32(hWnd, nIndex, dwNewLong);
        }
        return SetWindowLongPtr64(hWnd, nIndex, dwNewLong);
    }

    [DllImport("User32.dll", CharSet = CharSet.Auto, EntryPoint = "SetWindowLong")]
    public static extern IntPtr SetWindowLongPtr32(IntPtr hWnd, int nIndex, IntPtr dwNewLong);

    [DllImport("User32.dll", CharSet = CharSet.Auto, EntryPoint = "SetWindowLongPtr")]
    public static extern IntPtr SetWindowLongPtr64(IntPtr hWnd, int nIndex, IntPtr dwNewLong);

    public static long GetWindowLong(IntPtr hWnd, int nIndex)
    {
        if (IntPtr.Size == 4)
        {
            return GetWindowLong32(hWnd, nIndex);
        }
        return GetWindowLongPtr64(hWnd, nIndex);
    }

    [DllImport("User32.dll", EntryPoint = "GetWindowLong", CharSet = CharSet.Auto)]
    public static extern long GetWindowLong32(IntPtr hWnd, int nIndex);

    [DllImport("User32.dll", EntryPoint = "GetWindowLongPtr", CharSet = CharSet.Auto)]
    public static extern long GetWindowLongPtr64(IntPtr hWnd, int nIndex);

[DarranRowe]

It should also be noted that this is technically undocumented behaviour.
Neither SetWindowLong nor SetWindowLongPtr are documented to allow the use of GWL(P)_HWNDPARENT in the current version of the documentation.

[BlameTwo]

thanks