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
{
}

}
}
}