WPF : How to set a Dialog position to show at the center of the application?

Question

How to set Dialog\'s position that came from .ShowDialog(); to show at the center of the mainWindows.

This is the way I try to set position.

Answer 1

To get a WPF Dialog to position at the centre of a Windows Forms parent form I passed the parent form to the dialog since Application.Current didn't return the Windows Form parent (I assume it only works if the parent app is WPF).

public partial class DialogView : Window
{
    private readonly System.Windows.Forms.Form _parent;

    public DialogView(System.Windows.Forms.Form parent)
    {
        InitializeComponent();

        _parent = parent;
    }

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        this.Left = _parent.Left + (_parent.Width - this.ActualWidth) / 2;
        this.Top = _parent.Top + (_parent.Height - this.ActualHeight) / 2;
    }
}

set the WindowStartupLocation on the WPF Dialog:

and the way the Windows Form loads the WPF dialog is like this:

DialogView dlg = new DialogView();
dlg.Owner = this;

if (dlg.ShowDialog() == true)
{
    ...