title: prevent multiple open .XMAL windows when button pressed
body: <p>guys how can I prevent the opening already open WPF window (without using the user control and not adding in to windows form) when button press event ?</p>
  
  <p>I have following codes, but each time I press the button it will open WPF window according to button pressed amount.</p>
  
  <p>Dose anybody know how to prevent that error
  Thank you,</p>
  
  <pre><code> private void button1_Click(object sender, RoutedEventArgs e)
      {
          win2 v2 = new win2();
          v2.Show();
  
      }
  </code></pre>
  
  <p>here , when each time i click the above button it will open a window, but when its already open; if I clicked the same button it will open another window instead of focusing to the already open window.</p>
  
  <p>how can I prevent that?
  (I'm using C# )</p>