title: How to rotate camera in ViewPort3D using mouse in WPF?
body: <p>I was able to set the position and direction of the perspective camera placed in the viewport3d directly in XAML.
  But i would like to know how can i rotate the camera using the mouse input.
  I would prefer C# lang.
  I was actually stuck at the point how to rotate the camera using the input of the mouse.
  Please help me.
  It would be helpful if someone gives me a sample code....</p>