How to go full screen/full resolution?

How do I go fullscreen programmatically without getting any letterboxing?

 

Code (CSharp):

1. public void ToggleFullscreen(bool fullscreen)
2.      {
3.          Screen.fullScreen = fullscreen;
4.          if (Screen.fullScreen)
5.          {
6.              Screen.fullScreenMode = FullScreenMode.ExclusiveFullScreen;
7.          }
8.          else
9.          {
10.              Screen.fullScreenMode = FullScreenMode.Windowed;
11.          }
12.      }

something like this should work