C#此种方法导出Excel2007打不开，2003可以打开。怎么解决？多谢

C#此种方法导出Excel2007打不开，2003可以打开。如何解决？谢谢
 System.Web.UI.WebControls.DataGrid dgExport = null;
            // 当前对话
            System.Web.HttpContext curContext = System.Web.HttpContext.Current;
            // IO用于导出并返回excel文件
             System.IO.StringWriter strWriter = null;
            System.Web.UI.HtmlTextWriter htmlWriter = null;

            if (dt != null)
            {
                // 设置编码和附件格式
                curContext.Response.ContentType = "application/vnd.ms-excel";
                curContext.Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(strTitle, System.Text.Encoding.UTF8).ToString() + ".xls");
                curContext.Response.ContentEncoding = System.Text.Encoding.UTF7;
                curContext.Response.Charset = "";
                // 导出excel文件
                strWriter = new System.IO.StringWriter();

                htmlWriter = new System.Web.UI.HtmlTextWriter(strWriter);

                // 为了解决dgData中可能进行了分页的情况，需要重新定义一个无分页的DataGrid
                dgExport = new System.Web.UI.WebControls.DataGrid();
                dgExport.DataSource = dt.DefaultView;
                dgExport.AllowPaging = false;
                dgExport.DataBind();

                // 返回客户端
                dgExport.RenderControl(htmlWriter);
                curContext.Response.Write(strWriter.ToString());
                curContext.Response.End();
            } 
[最优解释]
static public void GridViewExportToExcel(Page pageParam, GridView gvParam,string fileName)
        {
            pageParam.Response.Clear();
            pageParam.Response.Buffer = true;

            pageParam.Response.Charset = "UTF-8";
            pageParam.Response.ContentType = "application/ms-excel";
            pageParam.Response.AppendHeader("Content-Disposition", "attachment;filename=" + fileName + ".xls");
            pageParam.Response.ContentEncoding = System.Text.Encoding.Default;

 
            System.IO.StringWriter oStringWriter = new System.IO.StringWriter();
            System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
            gvParam.RenderControl(oHtmlTextWriter);
            pageParam.Response.Output.Write(oStringWriter.ToString());
            pageParam.Response.Flush();
            pageParam.Response.End();
            pageParam.Response.Clear();

        }

这个方法兼容07与03都可以！
[其他解释]
 Response.Clear();
            Response.Buffer = false;
            Response.Charset = "GB2312";
            Response.AppendHeader("Content-Disposition", "attachment;filename=baobiao.xls");
            Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
            Response.ContentType = "application/ms-excel";
            Response.Write("<meta http-equiv=Content-Type content="text/html; charset=GB2312">");
            this.EnableViewState = false;
            System.IO.StringWriter oStringWriter = new System.IO.StringWriter();
            HtmlTextWriter oHtmlTextWriter = new HtmlTextWriter(oStringWriter);
            Repeater1.RenderControl(oHtmlTextWriter);
            Response.Write(oStringWriter.ToString());
            Response.End();


07可以打开