c# 新方法 数据导入Excel

//Excel导出方法
        public void ExportToExcel()
        {
            //模板文件路径
            string SaveDicPath = Server.MapPath("~/TemplateFiles/");
            string SaveFilePath = SaveDicPath +  "userfile.xls";

            //导出文件路径
            string TempPath = Server.MapPath("~/TempFiles/");
            if (!Directory.Exists(TempPath))
            {
                Directory.CreateDirectory(TempPath);
            }
            //excel文件名
            string FileName = DateTime.Now.ToString("yyyyMMddHHmmss") + ".xls";

            string newFileName = TempPath + FileName;

            //文件存在则删除,避免复制发生错误
            if (File.Exists(newFileName))
            {
                File.Delete(newFileName);
            }

            //将模板文件复制新的excel文件,用来下载
            File.Copy(SaveFilePath, newFileName);

            //初始化对象
            Application app = null;

            Workbook MyBook = null;

            Worksheet mySheet = null;
         
                app = new Application();

                MyBook = app.Workbooks.Open(newFileName, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

                mySheet = (Worksheet)MyBook.Worksheets[1];
           
                System.Data.DataTable dt = (System.Data.DataTable)Session["datatable"];
       
                //向EXCEL循环插入值
                for (int i = 0; i < dt.Rows.Count; i++)
                {           
                    mySheet.Cells[2 + i, 1] = dt.Rows[i][1].ToString().Trim(); //部门
                    mySheet.Cells[2 + i, 2] = dt.Rows[i][3].ToString().Trim(); //工号
                    mySheet.Cells[2 + i, 3] = dt.Rows[i][4].ToString().Trim(); //姓名
                    mySheet.Cells[2 + i, 4] = "";
                }

                //保存工作簿
                MyBook.Save();
                MyBook.Saved = true;

                if (mySheet != null)
                {
                    System.Runtime.InteropServices.Marshal.ReleaseComObject(mySheet);
                    mySheet = null;
                }
                if (MyBook != null)
                {
                    System.Runtime.InteropServices.Marshal.ReleaseComObject(MyBook);
                    MyBook = null;
                }

                //关闭对象
                app.Workbooks.Close();
                app.Quit();
           
                if (app != null)
                {
                    System.Runtime.InteropServices.Marshal.ReleaseComObject(app);
                    app = null;
                }

                GC.Collect(); //垃圾回收

                //跳转到相应的excel文件,进行下载
                Response.Redirect("..//TempFiles//" + FileName);         
        }