asp.net 下载文件（图片、word、excel等）

    string filePath = Server.MapPath("~/excel.xlsx"); 

        if (File.Exists(filePath))

        {

            FileStream fs = new FileStream(filePath, FileMode.Open);

            byte[] bytes = new byte[(int)fs.Length];

            fs.Read(bytes, 0, bytes.Length);

            fs.Close();

            Response.ContentType = "application/octet-stream";

            //通知浏览器下载文件而不是打开

            Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(Path.GetFileName(filePath), System.Text.Encoding.UTF8));

            Response.BinaryWrite(bytes);

            Response.Flush();

            Response.End();

        }