ImportExcel

  1         /// <summary>
        /// 在磁盘上创建一个临时的excel文件
        /// </summary>
        private void CreateExcelFile(string filePath, List<Entity> list)
        {
            if (File.Exists(filePath))
            {
                File.Delete(filePath);
            }

            OleDbConnection oleDbConn = new OleDbConnection();
            OleDbCommand oleDbCmd = new OleDbCommand();
            string sSql = "";

            try
            {
                //打开Microsoft.Jet.OleDb.4.0连接
                oleDbConn.ConnectionString = "Provider=Microsoft.Jet.OleDb.4.0;Data Source=" + filePath + @";Extended ProPerties=""Excel 8.0;HDR=Yes;""";
                oleDbConn.Open();
                oleDbCmd.CommandType = System.Data.CommandType.Text;
                oleDbCmd.Connection = oleDbConn;

                //写列名
                sSql = "CREATE TABLE [Sheet1](";
                for (int i = 0; i < this.gvData.Columns.Count - 2; i++)
                {
                    if (i < this.gvData.Columns.Count - 1)
                        sSql += this.gvData.Columns[i].HeaderText + " Text(200),";
                }
                oleDbCmd.CommandText = sSql.Remove(sSql.Length - 1) + ")";
                oleDbCmd.ExecuteNonQuery();

                //写行数据 
                for (int j = 0; j < list.Count; j++)
                {
                    sSql = "INSERT INTO [Sheet1] VALUES('";
                    sSql += list[j].列1 + " ','";
                    sSql += list[j].列2 + " ');";
                    oleDbCmd.CommandText = sSql;
                    oleDbCmd.ExecuteNonQuery();
                }
            }
            catch (System.Exception ex)
            {
                throw ex;
            }
            finally
            {
                //断开连接
                oleDbCmd.Dispose();
                oleDbConn.Close();
                oleDbConn.Dispose();
            }

        }

        /// <summary>
        ///     数据导出
        /// </summary>
        private void ImportExcel(List<Entity> list)
        {
            try
            {
                //随机文件名 
                string FileName = "temp//Sheet1.xls";
                //临时文件路径
                string filePath = this.Request.PhysicalApplicationPath + FileName;

                //创建临时文件
                CreateExcelFile(filePath, list);

                using (FileStream fs = new FileStream(filePath, FileMode.OpenOrCreate))
                {
                    //让用户输入下载的本地地址
                    Response.Clear();
                    Response.Buffer = true;
                    Response.Charset = "GB2312";

                    Response.AppendHeader("Content-Disposition", "attachment;filename=Sheet1.xls");
                    Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
                    Response.ContentType = "application/ms-excel";

                    // 读取excel数据到内存
                    byte[] buffer = new byte[fs.Length - 1];
                    fs.Read(buffer, 0, (int)fs.Length - 1);

                    // 写到aspx页面
                    Response.BinaryWrite(buffer);
                    Response.Flush();
                    this.ApplicationInstance.CompleteRequest(); //停止页的执行


                    fs.Close();
                    fs.Dispose();

                    //删除临时文件
                    File.Delete(filePath);
                }

            }
            catch (Exception ex)
            {
            }
        }

        

来自http://blog.csdn.net/houlinghouling/article/details/3851128