ShowDialog() behind the parent window

Question

I am using ShowDialog() with WindowStyle = WindowStyle.SingleBorderWindow; to open a modal window in my WPF (MVVM) application, but it lets me navigate to parent window using the Windows taskbar (Windows 7).

I've found an answer here: WPF and ShowDialog() but it isn't suitable for me because I don't need an "always on top" tool window.

Thanks in advance

Answer 1

Try setting the Owner property of the dialog. That should work.

Window dialog = new Window();
dialog.Owner = mainWindow;
dialog.ShowDialog();

Edit: I had a similar problem using this with MVVM. You can solve this by using delegates.

public class MainWindowViewModel
{
    public delegate void ShowDialogDelegate(string message);
    public ShowDialogDelegate ShowDialogCallback;

    public void Action()
    {
        // here you want to show the dialog
        ShowDialogDelegate callback = ShowDialogCallback;
        if(callback != null)
        {
            callback("Message");
        }
    }
}

public class MainWindow
{
    public MainWindow()
    {
        // initialize the ViewModel
        MainWindowViewModel viewModel = new MainWindowViewModel();
        viewModel.ShowDialogCallback += ShowDialog;
        DataContext = viewModel;
    }

    private void ShowDialog(string message)
    {
        // show the dialog
    }
}

Answer 2

I had this problem but as the Window was being opened from a view model I didn't have a reference to the current window. To get round it I used this code:

var myWindow = new MyWindowType();
myWindow.Owner = Application.Current.Windows.OfType<Window>().SingleOrDefault(x => x.IsActive);

You can use: myWindow.Owner = Application.Current.MainWindow;

However, this method causes problems if you have three windows open like this:

MainWindow
   |
   -----> ChildWindow1

               |
               ----->  ChildWindow2

Then setting ChildWindow2.Owner = Application.Current.MainWindow will set the owner of the window to be its grandparent window, not parent window.

Answer 3

When the parent window makes (and shows) the child window, that is where you need to set the owner.

public partial class MainWindow : Window
{

    private void openChild()
    {
        ChildWindow child = new ChildWindow ();
        child.Owner = this; // "this" is the parent
        child.ShowDialog();
    }
 }

Aditionally, if you don't want an extra taskbar for all the children... then

<Window x:Class="ChildWindow"           
        ShowInTaskbar="False" >
</Window>