title: How to underline the whole text of a WinRT TextBox?
body: <p>I want to set the underline for the whole text in a TextBox like setting TextDecorations in WPF TextBox. But there is no similar property in WinRT TextBox. So can anyone please suggest any solution to achieve my requirement?</p>
  
  <p>Note: I don't want to use RichEditBox</p>