title: Save WriteableBitmap to file using WPF
body: <p>I have:</p>
  
  <pre><code>WriteableBitmap bmp;
  </code></pre>
  
  <p>I basicly want to save it into a file on the disk like the following:</p>
  
  <pre><code>C:\bmp.png
  </code></pre>
  
  <p>I read some forums which mentions to read:</p>
  
  <pre><code>bmp.Pixels
  </code></pre>
  
  <p>and save those pixels into a <code>Bitmap</code> then use <code>Bitmap.SaveImage()</code> function. However, I can't access any <code>Pixels</code>. Apperantly my <code>WriteableBitmap</code> does not have any property named <code>Pixels</code>.</p>
  
  <p>I use .NET Framework 4.0.</p>