web页面导出到Excel乱码解决

引言:
前几天 在做web项目的时候 需要导出页面上的数据 到Excel里面
但有的时候出现乱码(有de时候不出现 很奇怪)
原来的代码是这样的:
        HttpContext.Current.Response.Clear();
        HttpContext.Current.Response.AddHeader("content-disposition",
        "attachment;filename=FileName.xls");
        HttpContext.Current.Response.Charset = "GB2312";
        HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");//.Unicode;//.UTF8;//
        HttpContext.Current.Response.ContentType = "xls"; //"application/vnd.xls";
        System.IO.StringWriter stringWrite = new System.IO.StringWriter();
        System.Web.UI.HtmlTextWriter htmlWrite = new HtmlTextWriter(stringWrite);
        mygridview.RenderControl(htw);
        HttpContext.Current.Response.Write(sw.ToString());
        HttpContext.Current.Response.End();

如何解决?

修改为下面的代码 问题就解决了

        HttpContext.Current.Response.ClearContent();
        HttpContext.Current.Response.Write("<meta http-equiv=Content-Type; content=text/html;charset=gb2312>");            
        HttpContext.Current.Response.AddHeader("content-disposition", "attachment; filename=MyExcelFile.xls");
        HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
        HttpContext.Current.Response.ContentType = "application/excel";
        System.IO.StringWriter sw = new System.IO.StringWriter();
        System.Web.UI.HtmlTextWriter htw = new System.Web.UI.HtmlTextWriter(sw);
        mygridview.RenderControl(htw);
        HttpContext.Current.Response.Write(sw.ToString());
        HttpContext.Current.Response.End();

仔细比较一下 就是

       HttpContext.Current.Response.Write("<meta http-equiv=Content-Type; content=text/html;charset=gb2312>"); 
      这句话起的作用 (这句话的作用是声明该网页使用gb2312进行编码)
      原来是 HttpContext.Current.Response.Charset = "GB2312";
      我以为有这句话 就可以  看来不行
      还是 使用 <meta http-equiv=Content-Type; content=text/html;charset=gb2312> 比较保险