任何想法如何解决问题？ ？ ？

Private void DownloadFile()
{
                DataSet objTable = ReadTableFromViewstate();
            if (objTable != null && objTable.Rows.Count > 0)
            {

                string strDownloadableFilename = "TestExcelFileName.xls";
                MemoryStream fs1 = new MemoryStream();
                if (CreateExcelFile.CreateExcelDocument(objTable,fs1))
                {
                    Response.Clear();
                        byte[] data1 = new byte[fs1.Length];
                        fs1.Read(data1,data1.Length);
                        fs1.Close();

                    Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
                    Response.AddHeader("Content-Disposition",string.Format("attachment; filename={0}",strDownloadableFilename));
                    Response.BinaryWrite(data1); ;
                   Response.End();

                }
                else
                {
                    LblErrorMessage.Text = "Error Exporting File.";
                }
            }

        }

..

public static bool CreateExcelDocument(DataSet ds,System.IO.Stream excelFileStream)
    {
        try
        {
            using (SpreadsheetDocument document = SpreadsheetDocument.Create(excelFileStream,SpreadsheetDocumentType.Workbook))
            {
                CreateParts(ds,document);
            }

            Trace.WriteLine("Successfully created: " + excelFileStream);
            return true;
        }
        catch (Exception ex)
        {
            Trace.WriteLine("Failed,exception thrown: " + ex.Message);
            return false;
        }
    }
..




private static void CreateParts(DataSet ds,SpreadsheetDocument document)
        {
            WorkbookPart workbookPart = document.AddWorkbookPart();
            Workbook workbook = new Workbook();
            workbookPart.Workbook = workbook;

            //  If we don't add a "WorkbookStylesPart",OLEDB will refuse to connect to this .xlsx file !

                WorkbookStylesPart workbookStylesPart = workbookPart.AddNewPart<WorkbookStylesPart>("rIdStyles");
            Stylesheet stylesheet = new Stylesheet();

            workbookStylesPart.Stylesheet = stylesheet;

            Sheets sheets = new Sheets();

            //  Loop through each of the DataTables in our DataSet,and create a new Excel Worksheet for each.
        uint worksheetNumber = 1;
        foreach (DataTable dt in ds.Tables)
        {
            //  For each worksheet you want to create
            string workSheetID = "rId" + worksheetNumber.ToString();
            string worksheetName = dt.TableName;

            WorksheetPart worksheetPart = workbookPart.AddNewPart<WorksheetPart>(workSheetID);
            WriteDataTableToExcelWorksheet(dt,worksheetPart);

            Sheet sheet = new Sheet() { Name = worksheetName,SheetId = (UInt32Value)worksheetNumber,Id = workSheetID };
            sheets.Append(sheet);

            worksheetNumber++;
        }

        workbook.Append(sheets);
    }