title: ref argument in C#
body: <p>First of all I am new to C# programming.</p>
  
  <p>I read the parameter of </p>
  
  <pre><code>ImageObj.getBounds(ref GraphicsUnit unit);
  </code></pre>
  
  <p>When I tried this,</p>
  
  <pre><code>ImageObj.getBounds(ref GraphicsUnit.Pixel);
  </code></pre>
  
  <p>I still got the error. But this seemed to work perfectly fine. </p>
  
  <pre><code>GraphicsUnit u = GraphicsUnit.Pixel;
  ImageObj.getBounds(ref u);
  </code></pre>
  
  <p>What is the difference between the two and how is the first wrong? Thank You.</p>