导出Excel类

using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Drawing;
using System.IO;

/// <summary>
///ExcelData 的摘要说明
/// </summary>
public class ExcelData
{
    public ExcelData()
    {
        //
        //TODO: 在此处添加构造函数逻辑
        //
  }
  public static void Export(System.Web.UI.Page page, System.Data.DataTable tab, string FileName)
  {
    System.Web.HttpResponse httpResponse = page.Response;
    DataGrid dataGrid = new DataGrid();
    dataGrid.DataSource = tab.DefaultView;
    dataGrid.AllowPaging = false;
    dataGrid.HeaderStyle.ForeColor = Color.White;
    dataGrid.HeaderStyle.BackColor = Color.FromName("#aaaadd");
    dataGrid.HeaderStyle.HorizontalAlign = HorizontalAlign.Center;
    dataGrid.HeaderStyle.Font.Bold = true;
    dataGrid.DataBind();
    httpResponse.AppendHeader("Content-Disposition", "attachment;filename=" +
      HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8)); //filename="*.xls";
    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);
    dataGrid.RenderControl(hw);

    string filePath = page.Server.MapPath(" .") + "\\Files\\" + FileName;
    if (!Directory.Exists(Path.GetDirectoryName(filePath)))
      Directory.CreateDirectory(Path.GetDirectoryName(filePath));

    System.IO.StreamWriter sw = System.IO.File.CreateText(filePath);
    sw.Write(tw.ToString());
    sw.Close();

    DownFile(httpResponse, FileName, filePath);

    httpResponse.End();
  }
  private static bool DownFile(System.Web.HttpResponse Response, string fileName, string fullPath)
  {
    try
    {
      Response.ContentType = "application/octet-stream";

      Response.AppendHeader("Content-Disposition", "attachment;filename=" +
        HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8) + ";charset=GB2312");
      System.IO.FileStream fs = System.IO.File.OpenRead(fullPath);
      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
        Response.BinaryWrite(readData);
        fPos += size;
      }
      fs.Close();
      System.IO.File.Delete(fullPath);
      return true;
    }
    catch
    {
      return false;
    }
  }
}