Is it possible to avoid Windows Forms namespace in WPF?

Question

The other day I've seen my second window (runs on a different thread) opens in Primary Screen while the MainWindow is Maximised in Secondary Screen. It opens wherever the MainWindow is if the MainWindow isn't Maximized. If I use same thread and set MainWindow as its Owner and WindowStartupLocation = WindowStartupLocation.CenterOwner, it also opens wherever the MainWindow is.

To solve the issue I'd to add <UseWindowsForms>true</UseWindowsForms> in <PropertyGroup> and this if/else:

public static void Activate(string message) {
    double left, top, width, height;
    if App.Current.MainWindow.WindowState == WindowState.Maximized) {
        var screen = System.Windows.Forms.Screen.FromHandle(new System.Windows.Interop.WindowInteropHelper(App.Current.MainWindow).Handle);
        left = screen.WorkingArea.Left;
        top = screen.WorkingArea.Top;
        width = screen.WorkingArea.Width;
        height = screen.Bounds.Height;
    }
    else {
        left = App.Current.MainWindow.Left;
        top = App.Current.MainWindow.Top;
        width = App.Current.MainWindow.Width;
        height = App.Current.MainWindow.Height;
    }
    App.Current.MainWindow.IsEnabled = false;
    var thread = new Thread(() => {
        window = new BusyWindow(width, height, message) {
            Left = left,
            Top = top
        };
        window.Show();
        Dispatcher.Run();
    });
    thread.SetApartmentState(ApartmentState.STA);
    thread.Start();
}

It works BUT looks weird because I've System.Windows.Forms and <UseWindowsForms>true</UseWindowsForms> in a WPF app!

EDIT

The original issue was WindowState:

public static void Activate(string message) {
    double left = App.Current.MainWindow.Left;
    double top = App.Current.MainWindow.Top;
    double width = App.Current.MainWindow.Width;
    double height = App.Current.MainWindow.Height;
    var state = App.Current.MainWindow.WindowState;
    App.Current.MainWindow.IsEnabled = false;
    var thread = new Thread(() => {
        window = new BusyWindow(width, height, message) {
            Left = left,
            Top = top,
            WindowState = state
        };
        window.Show();
        Dispatcher.Run();
    });
    thread.SetApartmentState(ApartmentState.STA);
    thread.Start();
    IsOpened = true;
}

If I keep WindowState = state, it opens the BusyWindow in primary screen when MainWindow is maximised in secondary screen so I've removed that and got into another issue! If I maximize MainWindow in Primary/Secondary screen and hit refresh, button that opens BusyWindow, the Top/Left of BusyWindow get the old Top/Left of MainWindow in Normal State. This behavior doesn't change even if I set Top/Left in OnSourceInitialized, here you can see the problem. If I move MainWindow between screens after maximizing it's alright.

I've seen some example like this where extern method's been used to get actual Top/Left, haven't tried that yet. Is there any simpler way to fix the issue?

Answer 1

Sure, you do not need to use Windows Forms in WPF. If however you need to use Windows Forms in WPF then you must reference Windows Forms.

In C# and in most languages, a namespace is just a name that qualifies things; for C# it qualifies classes. So I really do not understand what you are asking.