HTML：

<form id="upload">
        <div>
            <label for="myFile"></label>
            <div>
                <input type="file" id="myFile" />
            </div>
        </div>
        <button type="submit">Upload</button>
    </form>

使用Javascript：

// Hook into the form's submit event.
    $('#upload').submit(function () {

        // To keep things simple in this example,we'll
        // use the FormData XMLHttpRequest Level 2 object (which
        // requires modern browsers e.g. IE10+,Firefox 4+,Chrome 7+,Opera 12+ etc).
        var formData = new FormData();

        // We'll grab our file upload form element (there's only one,hence [0]).
        var opmlFile = $('#opmlFile')[0];

        // If this example we'll just grab the one file (and hope there's at least one).
        formData.append("opmlFile",opmlFile.files[0]);

        // Now we can send our upload!
        $.ajax({
            url: 'api/upload',// We'll send to our Web API UploadController
            data: formData,// Pass through our fancy form data

            // To prevent jQuery from trying to do clever things with our post which
            // will break our upload,we'll set the following to false
            cache: false,contentType: false,processData: false,// We're doing a post,obvIoUsly.
            type: 'POST',success: function () {
                // Success!
                alert('Woot!');
            }
        });

        // Returning false will prevent the event from
        // bubbling and re-posting the form (synchronously).
        return false;
    });

控制人如下：

using System;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Web;
using System.Web.Http;

class UploadController : ApiController
{
    public async void Post()
    {
        if (!Request.Content.IsMimeMultipartContent())
        {
            throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.NotAcceptable,"This request is not properly formatted"));
        }

        // We'll store the uploaded files in an Uploads folder under the web app's App_Data special folder
        var streamProvider = new MultipartFormDataStreamProvider(HttpContext.Current.Server.MapPath("~/App_Data/Uploads/"));

        // Once the files have been written out,we can then process them.
        await Request.Content.ReadAsMultipartAsync(streamProvider).ContinueWith(t =>
        {
            if (t.IsFaulted || t.IsCanceled)
            {
                throw new HttpResponseException(HttpStatusCode.InternalServerError);
            }

            // Here we can iterate over each file that got uploaded.
            foreach (var fileData in t.Result.FileData)
            {
                // Some good things to do are to check the MIME type before we do the processing,e.g. for XML:
                if (fileData.Headers.ContentType.MediaType.Equals("text/xml",StringComparison.InvariantCultureIgnoreCase))
                {
                    // And this is how we can read the contents (note you would probably want to do this asychronously
                    // but let's try keep things simple for now).
                    string contents = File.ReadAllText(fileData.LocalFileName);
                }
            }
        });
    }
}

该操作命中,但该文件未上传.