Hi,
OnRowDataBound event you can make the color against cell using conditions, Refer below sample.
protected void gv_OnRowDataBound(object sender, GridViewRowEventArgs e)
{
if(e.Row.RowType==DataControlRowType.DataRow)
{
int value=Convert.ToInt32(((Label)e.Row.FindControl("lblValue")).Text);
if(value > 1 && value < 20 )
{
e.Item.BackColor = System.Drawing.Color.Green;
}
else if(value > 21 && value < 40 )
{
e.Item.BackColor = System.Drawing.Color.Orange;
}
else if(value > 41 && value < 60 )
{
e.Item.BackColor = System.Drawing.Color.Red;
}
}
}