将gridview cell dd-MMM-yyyy格式化的日期值与当前日期进行比较

Question

我尝试将gridview单元格日期与当前日期进行比较，下面是我的代码。

protected void gridCustomer_RowDataBound(object sender, GridViewRowEventArgs e)  
{  
    if (e.Row.RowType == DataControlRowType.DataRow)  
    {

        //DateTime olddate = DateTime.Parse(e.Row.Cells[9].Text, CultureInfo.CreateSpecificCulture("en-US"));//Convert.ToDateTime(e.Row.Cells[9].Text);
        DateTime today = DateTime.Now;
        string s_today = today.ToString("dd-MMM-yyyy");
        DateTime formatted=Convert.ToDateTime(s_today);
        DateTime olddate = DateTime.ParseExact(e.Row.Cells[9].Text, "dd-MMM-yyyy", CultureInfo.InvariantCulture);
        //DateTime.TryParseExact(e.Row.Cells[9].Text, "dd-MMM-yyyy", CultureInfo.InvariantCulture, DateTimeStyles.None, out olddate);    

        if (olddate < formatted)
        {
            Label status = (Label)e.Row.FindControl("lblStatus");
            status.Text = "AutoHold";
        }       
    }   
}   

在过去的日子里，它总是得到01年1月1日和在gridview中显示＆＃39; 02-Mar-2015＆＃39;。

如果我使用注释代码，则会抛出错误

"String was not recognized as a valid DateTime". 

如何解决？