第一种：导出gridVIEW中的数据，用hansTABLE做离线表，将数据库中指定表中的所有数据按GRIDVIEW中绑定的ID导出

只能导出数据不能去操作相应的EXCEl表格，不能对EXCEL中的数据进行格式化操作，如：字体颜色，大小，单元格合并等

/// <summary>
    /// 导出
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void ImageButton2_Click(object sender, ImageClickEventArgs e)
    {
        string IDList = "'0'";
        for (int i = 0; i < GVData.Rows.Count; i++)
        {
            Label LabVis = (Label)GVData.Rows[i].FindControl("LabVisible");
            IDList = IDList + ",'" + LabVis.Text.ToString() + "'";
        }
        Hashtable MyTable = new Hashtable();
        MyTable.Add("TrueName", "姓名");
        MyTable.Add("DateType", "请假类别及事由");
        MyTable.Add("DateFR", "开始时间");
        MyTable.Add("DateTo", "结束时间");
        MyTable.Add("BuMenName", "组别");
        MyTable.Add("Days", "休假天数");
        MyTable.Add("SDays", "实修天数");
        MyTable.Add("Note", "备注");
        string sql = "select  TrueName "+"姓名"+",DateType "+"请假类别及事由"+",DateFR "+"开始时间"+",DateTO "+"结束时间"+",Note "+"备注"+",BuMenName "+"所属部门"+",Days "+"休假天数"+",SDays "+"实修天数"+" from T_ProjectLeave,Erpuser,erpbumen where T_ProjectLeave.userid= Erpuser.id and T_projectLeave.bumenID=erpbumen.ID and T_projectLeave.ID in (" + IDList + ") order by userID desc";
        ZWL.Common.DataToExcel.GridViewToExcel(ZWL.DBUtility.DbHelperSQL.GetDataSet(sql), MyTable, "Excel报表");
    }

GRIDVIEWToExcel方法：

  #region 将DataTable的数据导出显示为报表(不使用Excel对象，使用COM.Excel)这里必须要引入Com.EXCEl.dll文件

        #region 使用示例
        public static void GridViewToExcel(DataSet MyData, Hashtable nameList,string ReportTitle)
        {
            string FilePath = System.Web.HttpContext.Current.Server.MapPath("../") + "ReportFile\\";
            //利用excel对象
            DataToExcel dte = new DataToExcel();
            string filename = "";
            try
            {
                if (MyData.Tables[0].Rows.Count > 0)
                {
                    filename = dte.DataExcel(MyData.Tables[0], ReportTitle, FilePath, nameList);
                }
            }
            catch
            {}
            if (filename != "")
            {
                System.Web.HttpContext.Current.Response.Redirect("../ReportFile/" + filename, true);
            }
        }

        #endregion

        /// <summary>
        /// 将DataTable的数据导出显示为报表(不使用Excel对象)
        /// </summary>
        /// <param name="dt">数据DataTable</param>
        /// <param name="strTitle">标题</param>
        /// <param name="FilePath">生成文件的路径</param>
        /// <param name="nameList"></param>
        /// <returns></returns>
        public string DataExcel(System.Data.DataTable dt, string strTitle, string FilePath, Hashtable nameList)
        {
            COM.Excel.cExcelFile excel = new COM.Excel.cExcelFile();
            ClearFile(FilePath);
            string filename = DateTime.Now.ToString("yyyyMMddHHmmssff") + ".xls";
            excel.CreateFile(FilePath + filename);
            excel.PrintGridLines = false;

            COM.Excel.cExcelFile.MarginTypes mt1 = COM.Excel.cExcelFile.MarginTypes.xlsTopMargin;
            COM.Excel.cExcelFile.MarginTypes mt2 = COM.Excel.cExcelFile.MarginTypes.xlsLeftMargin;
            COM.Excel.cExcelFile.MarginTypes mt3 = COM.Excel.cExcelFile.MarginTypes.xlsRightMargin;
            COM.Excel.cExcelFile.MarginTypes mt4 = COM.Excel.cExcelFile.MarginTypes.xlsBottomMargin;

            double height = 1.5;
            excel.SetMargin(ref mt1, ref height);
            excel.SetMargin(ref mt2, ref height);
            excel.SetMargin(ref mt3, ref height);
            excel.SetMargin(ref mt4, ref height);

            COM.Excel.cExcelFile.FontFormatting ff = COM.Excel.cExcelFile.FontFormatting.xlsNoFormat;
            string font = "宋体";
            short fontsize = 9;
            excel.SetFont(ref font, ref fontsize, ref ff);

            byte b1 = 1,
                b2 = 12;
            short s3 = 12;
            excel.SetColumnWidth(ref b1, ref b2, ref s3);

            string header = "页眉";
            string footer = "页脚";
            excel.SetHeader(ref header);
            excel.SetFooter(ref footer);

            COM.Excel.cExcelFile.ValueTypes vt = COM.Excel.cExcelFile.ValueTypes.xlsText;
            COM.Excel.cExcelFile.CellFont cf = COM.Excel.cExcelFile.CellFont.xlsFont0;
            COM.Excel.cExcelFile.CellAlignment ca = COM.Excel.cExcelFile.CellAlignment.xlsCentreAlign;
            COM.Excel.cExcelFile.CellHiddenLocked chl = COM.Excel.cExcelFile.CellHiddenLocked.xlsNormal;

            // 报表标题
            int cellformat = 1;
            //   int rowindex = 1,colindex = 3;     
            //   object title = (object)strTitle;
            //   excel.WriteValue(ref vt, ref cf, ref ca, ref chl,ref rowindex,ref colindex,ref title,ref cellformat);

            int rowIndex = 1;//起始行
            int colIndex = 0;

            //取得列标题    
            foreach (DataColumn colhead in dt.Columns)
            {
                colIndex++;
                string name = colhead.ColumnName.Trim();
                object namestr = (object)name;
                IDictionaryEnumerator Enum = nameList.GetEnumerator();
                while (Enum.MoveNext())
                {
                    if (Enum.Key.ToString().Trim() == name)
                    {
                        namestr = Enum.Value;
                    }
                }
                excel.WriteValue(ref vt, ref cf, ref ca, ref chl, ref rowIndex, ref colIndex, ref namestr, ref cellformat);

              
            }

            //取得表格中的数据   
            foreach (DataRow row in dt.Rows)
            {
                rowIndex++;
                colIndex = 0;
                foreach (DataColumn col in dt.Columns)
                {
                    colIndex++;
                    if (col.DataType == System.Type.GetType("System.DateTime"))
                    {
                        object str;
                        try
                        {
                             str = (object)(Convert.ToDateTime(row[col.ColumnName].ToString())).ToString("yyyy-MM-dd");
                        }
                        catch
                        {
                            str = "";
                        }
                        excel.WriteValue(ref vt, ref cf, ref ca, ref chl, ref rowIndex, ref colIndex, ref str, ref cellformat);
                    }
                    else
                    {
                        object str = (object)row[col.ColumnName].ToString();
                        excel.WriteValue(ref vt, ref cf, ref ca, ref chl, ref rowIndex, ref colIndex, ref str, ref cellformat);
                    }
                }
            }
            int ret = excel.CloseFile();

            //   if(ret!=0)
            //   {
            //    //MessageBox.Show(this,"Error!");
            //   }
            //   else
            //   {
            //    //MessageBox.Show(this,"请打开文件c:\\test.xls!");
            //   }
            return filename;

        }

        #endregion

        #region  清理过时的Excel文件

        private void ClearFile(string FilePath)
        {
            String[] Files = System.IO.Directory.GetFiles(FilePath);
            if (Files.Length > 10)
            {
                for (int i = 0; i < 10; i++)
                {
                    try
                    {
                        System.IO.File.Delete(Files[i]);
                    }
                    catch
                    {
                    }

                }
            }
        }
        #endregion