You should explain better what your problem is, something more than "it is not working".
Anyway, the velocity of your player is 100px/s but you took App.GetFrameTime() as the velocity per frame of your background (Offset).
Compute your OffsetX and OffsetY (forgot Y at line 49 btw) the same way you're doing it for your player.
OffsetX = 100 * App.GetFrameTime(); Ditto for OffsetY
That is, of course, if you want the view to follow the player. Alternatively you could center the view on the player position with SetCenter.
Maybe you could also read again the thread you linked to.