public void ExportToExcel(string Filename, DataGrid gridview, Page page)
    {
        gridview.EnableViewState = false;
        gridview.AllowSorting = false;
        gridview.AllowPaging = false;
        gridview.HeaderStyle.ForeColor = System.Drawing.Color.Black;
        DataTable temp = (DataTable)ViewState["view"];//把你前边绑定数据的DataTable暂存ViewState.
        gridview.DataSource = temp;
        gridview.DataBind();

        page.Response.Clear();
        // 防止中文内容为乱码 
        page.Response.ContentEncoding = System.Text.Encoding.GetEncoding("utf-8");
        //可令中文文件名不为乱码 
        page.Response.AppendHeader("content-disposition", "attachment;filename=\"" + System.Web.HttpUtility.UrlEncode(Filename + DateTime.Now.ToShortDateString(), System.Text.Encoding.UTF8) + ".xls\"");
        System.IO.StringWriter sw = new System.IO.StringWriter();
        HtmlTextWriter htw = new HtmlTextWriter(sw);

        gridview.RenderControl(htw);
        page.Response.Write(sw.ToString());
        page.Response.End();
    }