Asp.Net导出Excel表格

public void ExportExcel(string sql)
        {
            using (SqlDataReader reader = DTcms.DBUtility.DbHelperSQL.ExecuteReader(sql))
            {
                if (reader.HasRows)
                {
                    IWorkbook wk = new HSSFWorkbook();
                    ISheet sheet = wk.CreateSheet("Sheet2");
                    int rowIndex = 0;
                    NPOI.SS.UserModel.IRow row1 = sheet.CreateRow(rowIndex);
                    row1.HeightInPoints = 25;
                    sheet.SetColumnWidth(0, 35 * 256);
                    row1.CreateCell(0).SetCellValue("网址");
                    rowIndex++;
                    string str = "http://video.kaola100.com/yxsp/yjjz/";
                    while (reader.Read())
                    {
                        IRow row = sheet.CreateRow(rowIndex);
                        row.HeightInPoints = 20;
                        ICell cell = row.CreateCell(0);

                        cell.SetCellValue(str + reader.GetInt32(0).ToString());
                      
                        rowIndex++;
                    }
                    MemoryStream ms = new MemoryStream();
                    wk.Write(ms);
                    Response.Clear();
                    Response.ClearHeaders();
                    Response.ClearContent();
                    Response.ContentType = "application/x-xls";
                    Response.AddHeader("Content-Disposition", string.Format("attachment;filename={0}.xls", DateTime.Now.ToString("yyyyMMddHHmmssfff")));
                    // Response.AddHeader("Content-Disposition", string.Format("attachment; filename={0}.xls", HttpUtility.UrlEncode(DateTime.Now.ToString("yyyy-MM-dd"), System.Text.Encoding.UTF8)));
                    Response.BinaryWrite(ms.ToArray());
                    wk = null;
                    ms.Close();
                    ms.Dispose();
                }
            }
        }