[Code] 导出excel2007

     private void ExportToExcel2007(DataGrid dtData)
        {
            if (dtData != null)
            {
                if (dtData.Items.Count == 0)
                {
                    Tools.Alert("当前无数据导出", this.Page);
                    return;
                }
                dtData.AllowPaging = false;
                dtData.AutoGenerateColumns = false;

                System.Web.HttpResponse httpResponse = Page.Response;
                httpResponse.Clear();
                httpResponse.Buffer = true;
                httpResponse.Charset = "gb2312";
                string fileName = DateTime.Now.ToString("yyyyMMddHHmmssms") + ".xls";                
                httpResponse.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));
                httpResponse.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
                httpResponse.ContentType = "application/ms-excel";
                System.IO.StringWriter tw = new System.IO.StringWriter();
                System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);
                dtData.RenderControl(hw);
                string directoryPath = Server.MapPath("~/") + "TempExcel";
                string filePath = Server.MapPath("~/") + "TempExcel\\" + fileName;
                if (!System.IO.Directory.Exists(directoryPath))
                {
                    System.IO.Directory.CreateDirectory(directoryPath);
                }                
                System.IO.StreamWriter sw = System.IO.File.CreateText(filePath);
                sw.Write(tw.ToString());
                sw.Close();
                DownFile(httpResponse, fileName, filePath);
                httpResponse.End();
            }
        }

        private bool DownFile(System.Web.HttpResponse Response, string fileName, string fullPath)
        {
            System.IO.FileStream fs = System.IO.File.OpenRead(fullPath);
            try
            {
                Response.ContentType = "application/octet-stream";

                Response.AppendHeader("Content-Disposition", "attachment;filename=" +
                HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8) + ";charset=GB2312");                
                long fLen = fs.Length;
                int size = 102400;//每100K同时下载数据 
                byte[] readData = new byte[size];//指定缓冲区的大小 
                if (size > fLen) size = Convert.ToInt32(fLen);
                long fPos = 0;
                bool isEnd = false;
                while (!isEnd)
                {
                    if ((fPos + size) > fLen)
                    {
                        size = Convert.ToInt32(fLen - fPos);
                        readData = new byte[size];
                        isEnd = true;
                    }
                    fs.Read(readData, 0, size);//读入一个压缩块
                    if (readData.Length > 0)
                        Response.BinaryWrite(readData);
                    fPos += size;
                }                          
                return true;
            }
            catch
            {
                return false;
            }
            finally
            {
                fs.Close();
                System.IO.File.Delete(fullPath);
            }
        }