title: C# SaveFileDialog setting one from multiple extensions Automatically adding extension when extensions are not typed
body: <p>I am using <code>SaveFileDialog</code> to save an image.</p>
  
  <p>The filter of the control is : <code>PNG|*png;|GIF|*gif;|BMP|*bmp;|JPEG|*jpg;*jpeg;</code></p>
  
  <p>However, if the extension is not typed in filename, it does not automatically add the extension.</p>
  
  <p>I know that i can set a <code>DefaultExt</code>, however, I do not know how to handle this when it comes to selecting from multiple extensions.</p>