asp.net mvc 上传下载文件的几种方式

view：

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title></title>
    <script src="~/Scripts/jquery-1.10.2.min.js"></script>
    <script src="~/Scripts/jquery.form.js"></script>
</head>
<body>
    <div>
        页面上传需要注意以下几点：<br />
        1、同一个页面可以有不止一个form但是不能嵌套<br />
        2、form：method="post" enctype="multipart/form-data"<br />
        3、input：type="file" name="XX" 必须要有name值<br />
    </div>

    <div style="margin-top:20px;">
        submit直接提交：提交后刷新页面,直接使用ajax不能把file传到后台处理<br />
        <form method="post" action="UpLoadPic" enctype="multipart/form-data">
            <input type="file" name="filename" id="filename" accept="image/*" />
            <input type="submit" value="提交" />
        </form>
    </div>

    <script>
        $(function () {
            var options = {
                success: function (data) {
                    alert("成功");
                }
            };

            //$("#myform1").ajaxForm(options);

            $("#myform1").submit(function () {
                $(this).ajaxSubmit(options);
                return false;
            });
        });
    </script>
    <div style="margin-top:20px;">
        jQuery.Form.js参照：http://www.cnblogs.com/heyuquan/p/form-plug-async-submit.html <br />
        http://www.vaikan.com/docs/jquery.form.plugin/jquery.form.plugin.html <br />
        http://www.cnblogs.com/xiaofeixiang/p/3676597.html <br />
        每次还会刷新页面
        <form id="myform1" method="post" action="UpLoadPic1" enctype="multipart/form-data">
            <input type="file" name="filename1" id="filename1" accept="image/*" />
            <input id="tijiao1" type="submit" value="提交" />
        </form>

        <div id="outputdiv"></div>
    </div>

    <script src="~/Scripts/ajaxfileupload.js"></script>
    <div style="margin-top:20px;">
        ajaxfileupload.js参照：http://www.cnblogs.com/kissdodog/archive/2012/12/15/2819025.html <br />
        <form method="post" action="GetPic" enctype="multipart/form-data">
            <input type="file" name="filename2" id="filename2" accept="image/*" />
            <input type="button" value="提交" onclick="f2submit();" />
        </form>
        <script>
            function f2submit() {
                //文件上传
                $.ajaxFileUpload({
                    url: 'UpLoadPic2',
                    secureuri: false,
                    fileElementId: 'filename2',
                    success: function () {
                        alert("成功");
                    },
                    error: function () {
                        alert("失败");
                    },
                });
                return false;
            }
        </script>
    </div>

    <script src="~/Scripts/uploadify/jquery.uploadify.min.js"></script>
    <div style="margin-top:20px;">
        jquery.uploadify.js参照：http://blog.sina.com.cn/s/blog_5079086b0101fkmh.html <br />
        局部刷新
        <form method="post" enctype="multipart/form-data">
            <input type="text" id="FilePathName" readonly="readonly" style="width: 300px;" />
            <input type="file" name="filename3" id="filename3" accept="image/*" />
            <input type="button" value="提交" onclick="f3submit()" />
        </form>
        <script>
            $(function () {
                $('#filename3').uploadify({
                    //'multi': false,
                    //'uploadLimit': 100,
                    auto: false, // 是否直接上传
                    //width: 64,
                    //height: 28,
                    buttonText: "浏览",
                    'fileSizeLimit': '20MB',
                    'fileTypeExts': '*.doc;*.docx;*.xlsx;*.pdf;*.ppt;*.pptx;*.xls;*.jpg;*.png;',
                    swf: '/Scripts/uploadify/uploadify.swf',
                    //uploader: '/Scripts/uploadify/UploadFile.ashx',
                    uploader: '/Home/UpLoadPic3',
                    onSelect: function (file) {
                        $("#FilePathName").val(file.name);
                    },
                    'onSelectError': function (file, errorCode, errorMsg) {
                        if (errorCode == -110) {
                            errorMsg = "文件大小不能超过20MB！";
                        }
                        else if (errorCode == -100) {
                            errorMsg = "已经有文件在队列中，请先取消之前的文件！";
                        }
                        else if (errorCode == -130) {
                            errorMsg = "文件格式错误，请选择正确格式的文件！";
                        }
                        else {
                            errorMsg = "未知错误！";
                        }
                        alert(errorMsg);

                        return false;
                    },
                    onUploadSuccess: function (file) {
                        alert("成功");
                    }
                });
            });
            function f3submit() {
                $('#filename3').uploadify('upload');
            }

        </script>
    </div>

    <div style="margin-top:20px;">
        FormData提交参照：http://www.cnblogs.com/hutuzhu/p/4409292.html <br />
        FormData为HTML5对象，只支持新浏览器<br />
        <form id="myform4" name="myform4">
            <input type="file" name="filename4" id="filename4" accept="image/*" />
            <input type="button" value="提交" onclick="f4submit()" />
        </form>
        <script type="text/javascript">
            function f4submit() {
                var form = document.getElementById("myform4");
                var formData = new FormData(form);
                var oReq = new XMLHttpRequest();
                oReq.onreadystatechange = function () {
                    if (oReq.readyState == 4) {
                        if (oReq.status == 200) {
                            alert(xhr.responseText);
                        }
                        else {
                            alert("失败");
                        }
                    }
                }
                oReq.open("POST", "UpLoadPic4");
                oReq.send(formData);
                return false;
            }
        </script>
    </div>

    <hr />
    <a href="/Home/GetFileByContent">根据文件内容下载二进制方式上传的文件</a>
    <br />
    <a href="/Home/GetFileByPath">根据文件保存路径下载上传的文件</a>
</body>
</html>

controller：

        public static string FilePath = string.Empty;
        public static byte[] FileContent;

        /// <summary>
        /// 视图
        /// </summary>
        /// <returns></returns>
        public ActionResult UpFile()
        {
            return View();
        }

        /// <summary>
        /// submit
        /// </summary>
        [HttpPost]
        public void UpLoadPic()
        {
            SaveFileDirect();
            //SaveFileStream();
            Response.Redirect("Upfile");
        }

        /// <summary>
        /// ajaxSubmit
        /// </summary>
        [HttpPost]
        public void UpLoadPic1()
        {
            SaveFileDirect();
            //SaveFileStream();
            Response.Redirect("Upfile");
        }

        /// <summary>
        /// ajaxfileupload.js
        /// </summary>
        [HttpPost]
        public void UpLoadPic2()
        {
            //SaveFileDirect();
            SaveFileStream();
        }

        /// <summary>
        /// jquery.uploadify.js
        /// </summary>
        public void UpLoadPic3()
        {
            //SaveFileDirect();
            SaveFileStream();
        }

        /// <summary>
        /// FormData
        /// </summary>
        public void UpLoadPic4()
        {
            //SaveFileDirect();
            SaveFileStream();
        }

        /// <summary>
        /// 直接保存上传文件到指定目录
        /// </summary>
        public void SaveFileDirect()
        {
            // 获取文件
            var upfile = Request.Files[];
            // 拼接保存路径
            string uppath = Server.MapPath("~/UpFile/") + Path.GetFileName(upfile.FileName);
            // 存入指定目录
            if (upfile.ContentLength > )
            {
                upfile.SaveAs(uppath);
            }

            FilePath = uppath;
            FileContent = null;
        }

        /// <summary>
        /// 通过二进制流保存文件，可以存入数据库
        /// </summary>
        public void SaveFileStream()
        {
            // 获取文件
            var upfile = Request.Files[];
            // 拼接保存路径
            string uppath = Server.MapPath("~/UpFile/") + Path.GetFileName(upfile.FileName);
            // 读入文件流
            byte[] temp = new byte[upfile.InputStream.Length];
            upfile.InputStream.Read(temp, , (int)upfile.InputStream.Length);
            // 写到指定目录
            using (FileStream fs = new FileStream(uppath, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite))
            {
                fs.Write(temp, , temp.Length);
            }
            FilePath = uppath;
            FileContent = temp;
        }

        /// <summary>
        /// FileContentResult方式下载
        /// </summary>
        /// <returns></returns>
        public FileResult GetFileByContent()
        {
            List<string> typeList = new List<string>() { ".png", ".jpg", ".jpeg" };
            string FileName = Path.GetFileName(FilePath);

            if (FileContent != null && FileContent.Length > )
            {
                if (typeList.Contains(Path.GetExtension(FileName)))
                {
                    return File(FileContent, "image/jpg");
                }
                // 存在fileDownLoad属性的FileResult以附件形式下载，默认会以内联方式打开
                return File(FileContent, "application/octet-stream", FileName);
            }
            return null;
        }

        /// <summary>
        /// FilePathResult方式下载
        /// </summary>
        /// <returns></returns>
        public FileResult GetFileByPath()
        {
            List<string> typeList = new List<string>() { ".png", ".jpg", ".jpeg" };
            string FileName = Path.GetFileName(FilePath);

            if (FileName != null)
            {
                if (typeList.Contains(Path.GetExtension(FileName)))
                {
                    return File(FilePath, "image/jpg");
                }
                // 存在fileDownLoad属性的FileResult以附件形式下载，默认会以内联方式打开
                return File(FilePath, "application/octet-stream", FileName);
            }
            return null;
        }