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I have been creating a Calculator in C# and it’s a WPF Application. I have enabled a few keys like numbers, addition key, multiplication key etc. As I have enabled few keys only, the user cannot exit the application using alt+F4. I have used PreviewKeyDown Even and I have handled other irrelevant keys. Is there a solution to enable alt+F4 ?
Thanks in advance.

Here is a piece of my code:

private void Window_PreviewKeyDown(object sender, KeyEventArgs e)

            switch (e.Key)
                case Key.D0: Number0_Click(sender, e); break;
                case Key.D1: Number1_Click(sender, e); break;
                case Key.D2: Number2_Click(sender, e); break;
                case Key.NumPad6: Number6_Click(sender, e); break;
                case Key.NumPad7: Number7_Click(sender, e); break;
                case Key.NumPad8: Number8_Click(sender, e); break;
                case Key.NumPad9: Number9_Click(sender, e); break;

                    e.Handled = true;
Updated 1-Apr-14 0:14am

I don't know about WPF. I guess the issue is due to e.Handled = true; which blocks the event from executing the default behavior i.e. for Alt+F4 close the window.
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Change the default code:
    e.Handled = false;

If you return true for everything you don't do anything with, none of those will ever work...
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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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