You will have a defined RowDataBound handler for a given grid. You should know the Grid ID at all time as the event for a given grid will be called only when you trigger the DataBind event.
This event is for handling row level feature, example:
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) {
if(e.Row.RowType == DataControlRowType.DataRow)
{
Decimal Price = (decimal)DataBinder.Eval(e.Row.DataItem, "Price");
if(Price<20)
{
e.Row.ForeColor = System.Drawing.Color.Red;
e.Row.BackColor = System.Drawing.Color.Black;
}
}
}