How to compare Date values in DataGrid with Current date?

Question

I have tried with
protected void gridCustomer_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
DateTime olddate = Convert.ToDateTime(e.Row.Cells[9].Text);  /*Error : String was not recognized as a valid DateTime.*/
DateTime today = DateTime.Now;

if (olddate > today)

                {

                    Label status = (Label) e.Row.FindControl("lblStatus");

                    status.Text = "AutoHold";

                }    

}
}