calculating salary in a grid where at runtime the values has to be inputted

protected void GridView_RowDataBound(object sender, GridViewRowEventArgs e)
{

if (e.Row.RowType == DataControlRowType.DataRow)
{
TotalPrice += Convert.ToInt32(DataBinder.Eval(e.Row.DataItem, "Total"));
}
if (e.Row.RowType == DataControlRowType.Footer)
{
TextBox lbltotal = (TextBox)e.Row.FindControl("txttotalprice");
lbltotal.Text = TotalPrice.ToString();
}