title: What does IntPtr.Zero mean in System.Drawing.Graphics
body: <p>I need to get the exact meaning of IntPtr.Zero in below function.
  I used this function for convert word document text range position pixel value to WPF unit value.</p>
  
  <pre><code>Graphics g = Graphics.FromHwnd(IntPtr.Zero)
  </code></pre>
  
  <p>That normally said to pass the handle,but I didn't get it.</p>