title: How to draw a line in windows which fill width in xaml
body: <p>I have a window which is its size can be change during run time by user.</p>
  
  <p>I want to draw a horizontal line which extends to the width of window.</p>
  
  <p>I can do this by code behind (on window resize event, change the size of line), </p>
  
  <p>but  am looking for a way to change the size of line in xaml, so for example bind x1,x2,y1 and y2 to their parents (or window) size in a way that line resize itself when the size of window changes. </p>
  
  <p>How can I do this?</p>