A: 

Use .defaultcellstyle.backcolor. It works for us.

Novice Coder
But i just want to color a single Cell.and i tried that for the whole row but it doesnt workI can not change any cellstyle....'that's so weird
Willem
grid.Rows[0].DefaultCellStyle.BackColor = Color.Red; works for the whole row for me... But this is for the whole row, not an individual cell.
Novice Coder
We are using this to display red for expired dates and yellow for products which will expire soon.
Novice Coder
i tried that too but it doesnt work at all I never change to color of the row
Willem
Try it once more after your grid is fully displayed. Instead of setting the color during fill out, fill it up, display and then loop through all rows and then set the color.
Novice Coder
A: 

If you want to change the backcolor of the entire grid do this:

        GridView1.BackColor = System.Drawing.Color.Navy;
RJ
just want to change the color of a cellbut my grid is databoud so i dont know if it will work then
Willem