问Excel导出问题

EN

public class HomeController : Controller
    {
        public ActionResult Index()
        {
            ViewBag.Message = "Precise Technology Consultants";
            var DataContext = new EmployeeAtdDataContext();
            //var EmployeeAtd = DataContext.GetAttendance_Sp();
            IEnumerable<GetAtdRecord_SpResult> EmployeeAtd = DataContext.GetAtdRecord_Sp(null).ToList();
            var names = (from n in DataContext.EmployeeAtds select n).Distinct();
            ViewData["EmplID"] = new SelectList(names, "EmplID", "EmplName");
            return View(EmployeeAtd);

        }

        public ActionResult About()
        {
            return View();
        }

        public ActionResult ToExcel()
        {
            var DataContext = new EmployeeAtdDataContext();

            var grid = new GridView();
            grid.DataSource = DataContext.GetAtdRecord_Sp(null).ToList();
            grid.DataBind();

            Response.ClearContent();
            Response.Buffer = true;
            Response.AddHeader("content-disposition", "attachment; filename=AttendanceSheet.xls");
            Response.ContentType = "application/ms-excel";

            Response.Charset = "";
            StringWriter sw = new StringWriter();
            System.Web.UI.HtmlTextWriter htw = new System.Web.UI.HtmlTextWriter(sw);

            grid.RenderControl(htw);

            Response.Output.Write(sw.ToString());
            Response.Flush();
            Response.End();
            return RedirectToAction("Index");
        }

WITH Times AS
(   SELECT  emp.EmplID, 
            emp.EmplName,
            InTime = MIN(atd.RecTime),
            OutTime = MAX(atd.RecTime),
            TimeWorked = DATEDIFF(MINUTE, MIN(atd.RecTime), MAX(atd.RecTime)),
            OverTime = DATEDIFF(MINUTE, MIN(atd.RecTime), MAX(atd.RecTime)) - 480,
            [DateVisited] = atd.RecDate
    FROM    AtdRecord atd 
            INNER JOIN HrEmployee emp 
                ON atd.EmplID = emp.EmplID 
    GROUP BY emp.EmplID, emp.EmplName, atd.RecDate
    HAVING COUNT(atd.RecTime) > 1
)
SELECT  t.EmplID,
        t.EmplName,
        t.InTime,
        t.OutTime,
        t.DateVisited,

        TimeWorked = CONVERT(CHAR(5), DATEADD(MINUTE, t.TimeWorked, 0), 8),
        OverTime = CASE WHEN t.OverTime < 0 THEN '-' ELSE '' END +
                                CONVERT(CHAR(5), DATEADD(MINUTE, ABS(t.OverTime), 0), 8)
FROM    Times t