我有以下代码 . 我想使用c＃asp.net在.xlsx中为excel 2010或更高版本生成excel但无法生成我的代码如下

string attachment = "attachment; filename=Students.xlsx";
            HttpContext.Current.Response.ClearContent();
            HttpContext.Current.Response.AddHeader("content-disposition", attachment);
            HttpContext.Current.Response.ContentType = "application/application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
            StringWriter stw = new StringWriter();
            HtmlTextWriter htextw = new HtmlTextWriter(stw);
            excel.RenderControl(htextw);
            HttpContext.Current.Response.Write(stw.ToString());
            FileInfo fi = new FileInfo(Server.MapPath("~/css/main.css"));
            System.Text.StringBuilder sb = new System.Text.StringBuilder();
            StreamReader sr = fi.OpenText();
            while (sr.Peek() >= 0)
            {
                sb.Append(sr.ReadLine());
            }
            sr.Close();
            Response.Write("<html><head><style type='text/css'>" + sb.ToString() + "</style></head>" + stw.ToString() + "</html>");
            stw = null;
            htextw = null;
            Response.Flush();
            Response.End();

指导我如何在excel 2010中打开我的文件

c# asp.net excel