How to change the aspect ratio of an Windows media player by using C#

Question

Watching a Video on windows media player will produce black bars on the left and right.

this.MPlayer.stretchToFit = true;
AxWindowsMediaPlayer mPlayer = this.MPlayer;
mPlayer.URL = "Location of a file";

Below attached file output of the code.

 

Please suggest me how to change the aspect ratio of an Windows media player.