Response.Clear();  //清空输出流
        Response.Buffer = true; //开启缓冲输出  
        Response.Charset = "GB2312";  //输出字符集中文
        Response.AppendHeader("Content-Disposition", "attachment;filename=你要存成的文件名字.xls");
        // 如果设置为 GetEncoding("GB2312");否则导出的文件将会出现乱码！！！
       
        Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
        Response.ContentType = "application/ms-excel";//设置输出文件类型为excel文件。
        System.IO.StringWriter oStringWriter = new System.IO.StringWriter();
        System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
        this.GridView1.RenderControl(oHtmlTextWriter);    //GridView 内容输出到流,其他数据组件类似
        Response.Output.Write(oStringWriter.ToString());
        Response.Flush();
        Response.End();

  注意:另外一定要加上下面的方法  这个是重写的注册方法,否则会报错
 public override void VerifyRenderingInServerForm(Control control)
    {

    }