把Excel中的数据导入gridView显示，再导入数据库

  using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.OleDb;

//创建一个临时DataTable，为了把Excel中的数据导入gridView后再导入数据库。
        private static DataTable dtTemp;

        /// <summary>
        /// 把Excel导入Gridview，首先把文件上传到服务器
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void btnImport_Click(object sender, EventArgs e)
        {
            //导入Excel文件
            //检查文件是否存在
            //HasFile用来检查上传文件控件FileUpload是否有指定文件
            if (FileUpload1.HasFile == false)
            {
                Page.ClientScript.RegisterStartupScript(Page.GetType(), "message", "<script language='javascript' defer>alert('请您选择Excel文件! ');</script>");
                return;//当无文件时,返回
            }

            string filename = DateTime.Now.ToString("yyyymmddhhMMss") + FileUpload1.FileName;
            //获取Execle文件名  DateTime日期函数
            string savePath = Server.MapPath(("../Doc/") + filename);//Server.MapPath 获得虚拟服务器相对路径

            //如果已经存在就清空
            ClearFile(Server.MapPath("../Doc/"));

            FileUpload1.SaveAs(savePath);                        //SaveAs 将上传的文件内容保存在服务器上
            DataTable dt = createDataSource(savePath);
            if (dtTemp == null)
            {
                dtTemp = new DataTable();
                dtTemp = dt;
            }

            GridView1.DataSource = dt;
            GridView1.DataBind();
        }

        /// <summary>
        /// 从gridview导入数据库
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void btnSubmit_Click(object sender, EventArgs e)
        {
            DataTable dt = new DataTable();
            dt = dtTemp;

            for (int i = 0; i < dt.Rows.Count; i++)
            {
                //导入数据库的代码省略
            }
            Response.Write("<script>alert('添加成功！！')</script>");


        }
     
        /// <summary>
        /// 将路径下的Excel文件转换为DataTable类型的数据源
        /// </summary>
        /// <param name="strPath">Excel路径</param>
        /// <returns></returns>
        private DataTable createDataSource(string strPath)
        {
            string strCon;
            strCon = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + strPath + ";Extended Properties=Excel 8.0";
            OleDbConnection con = new OleDbConnection(strCon);
            OleDbDataAdapter da = new OleDbDataAdapter("select * from [Sheet1$]", con);
            DataTable dt = new DataTable();
            da.Fill(dt);
            return dt;
        }

        /// <summary>
        /// 将Excel文件暂存到服务器端的一个文件夹中，用这个方法删除掉
        /// </summary>
        /// <param name="FilePath">Excel路径</param>
        private void ClearFile(string FilePath)
        {
            String[] files = System.IO.Directory.GetFiles(FilePath);
            if (files.Length > 5)
            {
                for (int i = 0; i < 5; i++)
                {
                    try
                    {
                        System.IO.File.Delete(files[i]);
                    }
                    catch
                    {
                    }

                }
            }
        }