Reopening a dialog box after it is closed.

I have the following code:

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Window1 test =  new Window1();

private void button1_click(object sender, RoutedEventArgs e)

{  

     test.Owner = this;

     test.ShowDialog();

}

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If using Windows forms: On the Widows1 form I have a button with the property set as CancelButton. When I cancel it I can re-open it with the button click event on the main form without a problem.

When I try the same thing in WPF with the button on Windows1 property set to IsCancel, I get an Exception error: Cannot set visibility or call show [...] after a window has closed.

Any solutions to this?