Show gridview rows in a different colour

You can use and handle the RowDataBound event and then manipulate the DataRow.

 decimal priceTotal = 0;
int quantityTotal = 0;
void detailsGridView_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
// add the UnitPrice and QuantityTotal to the running total variables
priceTotal += Convert.ToDecimal(DataBinder.Eval(e.Row.DataItem, _
"UnitPrice"));
quantityTotal += Convert.ToInt32(DataBinder.Eval(e.Row.DataItem, _
"Quantity"));
}
else if (e.Row.RowType == DataControlRowType.Footer)
{
e.Row.Cells[0].Text = "Totals:";
// for the Footer, display the running totals
e.Row.Cells[1].Text = priceTotal.ToString("c");
e.Row.Cells[2].Text = quantityTotal.ToString("d");

e.Row.Cells[1].HorizontalAlign = _
e.Row.Cells[2].HorizontalAlign = HorizontalAlign.Right;
e.Row.Font.Bold = true;
}
}