title: Multiline mask for MaskedTextBox
body: <p>I have a <code>MaskedTextBox</code> in my Winforms application. I need a multiline mask on it, f.e:</p>
  
  <pre><code>"999999\r\n
   999999\r\n
   999999\r\n
   00/00/0000"
  </code></pre>
  
  <p>I read the <a href="http://msdn.microsoft.com/en-us/library/system.windows.forms.maskedtextbox.mask%28v=vs.110%29.aspx" rel="noreferrer">msdn documentation</a> and was suprised to see that there is no "new line"or something like that.</p>
  
  <p>I know that i can write my own user control to fix this issue, but a masked textbox would be an easier solution.
  So i have 2 Questions: Is there a way to add a new Line to a mask?
  If not, why does the Control supports multiline - isnt that useless?</p>
  
  <p>Thanks in advance</p>