c# - Constant based on variable? -

i'm making small game in xna @ moment.

and want base size of array on screen's resolution.

i did this:

public const int intboardheight = (graphicsadapter.defaultadapter.currentdisplaymode.height -150) / 10 ; public const int intboardwidth = (graphicsadapter.defaultadapter.currentdisplaymode.width - 200) / 10;  public bool[,] gameboard = new bool[intboardheight,intboardwidth]; public bool[,] gameboardupdate = new bool[intboardheight, intboardwidth]; public int[,] gameboardint = new int[intboardheight, intboardwidth]; 

but gives me error "the expression being assigned 'game_of_life_2.game1.intboardheight' must constant".

so, how base constant on variable?

thanks in advance!

simon.

edit: guys! worked well!

you can't. make public static readonly int