MVC的的文件下载如何实现

Question

上网搜了搜 以前WebForm的好多方法都不支持了！还有控件，相问问有没有什么方法能实现
我自己也写了一个,在Controller中写了一个把文件下载到本地的方法带有2个参数 文件名和路径
然后再View中的一个超链接想调用这个方法，就是点超链接然后下载！可是 最后那个下载路径完全乱套了！

Answer 1

给你看一下我以前做的一个MVC文件下载：
Controller：
 /// <summary>
        /// 下载文件，需传入Filename、Filepath，及Extension
        /// </summary>
        /// <returns></returns>
        public ActionResult DownloadFile()
        {
            //判断用户是否登录
            if (Session["user"] == null)
            {
                Response.Write("Sorry,please login");
                return null;
            }
            try
            {
                if (CommonFunctions.CommonFunctions.hasSecurity(((User)Session["user"]).Role_id, 17))
                {
                    string doc_serial_no = Request.QueryString["doc_serial_no"];
                    using (MDMSDBContext dbContext = new MDMSDBContext())
                    {
                        var js_record = from t_doc in dbContext.DsDocuments
                                        join t_doc_type in dbContext.DsDocTypes on t_doc.Type_id equals t_doc_type.Id
                                        where t_doc.Serial_No == doc_serial_no
                                        select new
                                        {
                                            doc_name = t_doc.Name,
                                            doc_path = t_doc.path,
                                            doc_extention = t_doc_type.Extension_name
                                        };
                        string filename = js_record.First().doc_name;
                        string filepath = js_record.First().doc_path;
                        string fileextension = js_record.First().doc_extention;                        filepath = Server.MapPath(Request.ApplicationPath + "/Documents/") + filepath;
                        System.IO.FileStream r = new System.IO.FileStream(filepath, System.IO.FileMode.Open);    //创建文件流读取要下载的文件
                        Response.Clear();   //清空响应流
                        Response.AddHeader("connection", "Keep-Alive");
                        Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(filename) + "." + fileextension);    //指定文件名
                        //Response.ContentType = fileextension;    //
                        Response.AddHeader("Content-Length", r.Length.ToString());   //指定文件长度
                        while (true)
                        {
                            byte[] buffer = new byte[1024];     //开辟1024的缓冲区
                            int len = r.Read(buffer, 0, 1024);
                            if (len == 0)    //到达文件末尾，跳出循环
                            {
                                break;
                            }
                            if (len == 1024)    //读出的文件长度等于1024，就向客户端发送数据
                            {
                                Response.BinaryWrite(buffer);
                            }
                            else    //如果小于1024，重新定义长度
                            {
                                byte[] b = new byte[len];
                                for (int i = 0; i < len; i++)
                                    b[i] = buffer[i];
                                Response.BinaryWrite(b);   //数据发送到客户端                            }
                        }
                        r.Close();   //关闭流
                        Response.End();  //下载完成                        updateDocument(doc_serial_no);                        string log_content = "Download File Name:" + filename + "<br>";                        CommonFunctions.CommonFunctions.writeOperationLog("Download File", "Download File", ((User)Session["user"]).Name, log_content);
                    }                }
                else
                {
                    Response.Write("You have no security to download this document!");
                }
            }
            catch (Exception ex)
            {
                Response.Write("Sorry,download file error！<br>" + ex.ToString());
            }            return null;
        }
View中用超链接指向这个Controller就行了，我是在js脚本中创建超链接的：obj_td_title.innerHTML = '<a class="index_page_icon2" href="../Download.ashx/DownloadFile?doc_serial_no=' + jsonDoc[i].Serial_No +
                                         '" target="_blank" title="' + jsonDoc[i].Description + '">' + jsonDoc[i].Name + '</a>';