<div>

        <span>最原始的方式</span><br />

        <span>条件1:必须是 post 方式</span><br />

        <span>条件2:必须注明是传输文件 enctype="multipart/form-data"</span><br />

        <span>条件3:必须设置name属性,name="myFile"</span><br />

        <form id="myForm1" method="post" enctype="multipart/form-data" action="http://localhost:42561/api/upload/upload">

            <input type="file" name="myFile" />

            <input type="submit" value="原始form表单上传文件" />

        </form>

    </div>

        public async Task<HttpResponseMessage> Upload()

        {

            var files = HttpContext.Current.Request.Files;

            var path = HttpContext.Current.Server.MapPath("/img/");

            if (files.Count > )

            {

                foreach (string file in files)

                {

                    //这里的 file ,就是 input[type="file"] 标签的name属性的值,

                    //这也是为什么上传文件,input[type="file"] 标签必须设置name属性的值的原因之一.

                    var img = files[file];

                    if (img?.ContentLength > )

                    {

                        var fileName = img.FileName;

                        await Task.Run(() => img.SaveAs(path + fileName));

                    }

                }

                return new HttpResponseMessage(HttpStatusCode.OK);

            }

            return Request.CreateErrorResponse(HttpStatusCode.BadRequest, "没有文件");

        }

    <div>

        <span>利用FormData上传单个文件</span><br />

        <form id="myForm2">

            <input type="file" name="myFile" />

            <input type="button" value="利用FormData上传单个文件" onclick="uploadOne()" />

        </form>

    </div>

        function uploadOne() {

            var url = "http://localhost:42561/api/upload/upload";

            //这里之所以会写成[0],是因为$(...)是JQ对象,是个数组,而这里需要传入的是JS对象.

            var data = new FormData($("#myForm2")[0]);

            $.ajax({

                url: url,

                data: data,

                type: "post",

                processData: false,//表示提交的时候不会序列化 data,而是直接使用 data,默认为 true

                contentType: false,//表示不要去设置Content-Type请求头

                cache: false,//设置为 false 将不会从浏览器缓存中加载请求信息。

                success: function () { }

            });

        }

    <div>

        <span>利用FormData上传多个文件</span><br />

        <form id="myForm3">

            <input type="file" id="myFile" multiple />

            <input type="button" value="利用FormData上传多个文件" onclick="uploadSome()" />

        </form>

    </div>

        function uploadSome() {

            var url = "http://localhost:42561/api/upload/upload";

            var data = new FormData();

            var files = $("#myFile")[0].files;

            for (var i = 0; i < files.length; i++) {

                //这里的 myFile0,myFile1,myFile2就是input type="file" 标签的name属性,所以标签里面可以不用写name属性了

                data.append("myFile" + i, $("#myFile")[0].files[i]);

            }

            $.ajax({

                url: url,

                data: data,

                type: "post",

                processData: false,

                contentType: false,

                cache: false,

                success: function () { }

            });

        }

    <div>

        <span>分片上传单个文件</span><br />

        <form id="myForm4">

            <input type="file" id="myFileStep" />

            <input type="button" value="分片上传单个文件" onclick="uploadStep()"/>

        </form>

        <br />

        <span class="result"></span>

    </div>

   function uploadStep() {

            var upload = function (file, skip) {

                var data = new FormData();

                var blockSize = 1000;

                var nextSize = Math.min((skip + 1) * blockSize, file.size);

                var fileData = file.slice(skip * blockSize, nextSize);

                data.append("myFile", fileData);

                //由于传输的是二进制数据(fileData),后台(MVC或者Api无法通过files[0].FileName获取文件名

                //所以只能通过构造form表单数据传递(键值对形式,fileName=xxx.jpg&aaa=yyy),后台再通过request.Form[fileName]获取

                data.append("fileName", file.name);

                var url = "http://localhost:42561/api/upload/uploadStep";

                $.ajax({

                    url: url,

                    type: "POST",

                    data: data,

                    processData: false, // 告诉jQuery不要去处理发送的数据

                    contentType: false, // 告诉jQuery不要去设置Content-Type请求头

                    success: function () {

                        $(".result").html("已经上传了" + (skip + 1) + "块文件");

                        if (file.size <= nextSize) { //如果上传完成，则跳出继续上传

                            alert("上传完成");

                            return;

                        }

                        upload(file, ++skip); //递归调用

                    }

                });

            };

            var file = $("#myFileStep")[0].files[0];

            upload(file, 0);

        }

        public HttpResponseMessage UploadStep()

        {

            var path = HttpContext.Current.Server.MapPath("/img/");

            var name = HttpContext.Current.Request.Form["fileName"];

            var filePath = path + name;

            //创建一个追加（FileMode.Append）方式的文件流

            using (FileStream fs = new FileStream(filePath, FileMode.Append, FileAccess.Write))

            {

                var file = HttpContext.Current.Request.Files[];

                //方法一

                using (BinaryWriter bw = new BinaryWriter(fs))

                {

                    //读取文件流

                    BinaryReader br = new BinaryReader(file.InputStream);

                    //将文件流转成字节数组

                    byte[] bytes = br.ReadBytes((int)file.InputStream.Length);

                    //将字节数组追加到文件

                    bw.Write(bytes);

                    br.Dispose();

                }

                //方法二

                //Stream sm = file.InputStream;

                //byte[] bytes = new byte[sm.Length];

                //sm.Read(bytes, 0, bytes.Length);

                //fs.Write(bytes, 0, bytes.Length);

                //sm.Dispose();

            }

            return new HttpResponseMessage(HttpStatusCode.OK);

        }