文件上传与jQuery AJAX和处理程序(ashx)不工作

我试图上传一个图像文件与jQuery AJAX和通用处理程序。但似乎文件没有传递给处理程序。提交后，context.Request.Files[0];始终为空:-/

我做错了什么?

HTML:

<form id="form1" runat="server" method="post" enctype="multipart/form-data">
    <input name="file" id="file" type="file" />
    <input id="save" name="submit" value="Submit" type="submit" />
</form>

JS:

$().ready(function ()
{
    $('#file').change(function () 
    {
        sendFile(this.files[0]);
    });
});
function sendFile(file) 
{
    $.ajax({
        type: 'post',
        url: 'FileUpload.ashx',
        data: file,
        success: function () {
            // do something
        },
        xhrFields:
        {
            onprogress: function (progress) 
            {
                // calculate upload progress
                var percentage = Math.floor((progress.total / progress.totalSize) * 100);
                // log upload progress to console
                console.log('progress', percentage);
                if (percentage === 100) {
                    console.log('DONE!');
                }
            }
        },
        processData: false,
        contentType: 'multipart/form-data'
    });
}

ASHX:

public void ProcessRequest (HttpContext context) 
{
    HttpPostedFile file = context.Request.Files[0];
    if (file.ContentLength > 0)
    {
        //do something
    }
}

///create a new FormData object
var formData = new FormData(); //var formData = new FormData($('form')[0]);
///get the file and append it to the FormData object
formData.append('file', $('#file')[0].files[0]);
///AJAX request
$.ajax(
{
    ///server script to process data
    url: "fileupload.ashx", //web service
    type: 'POST',
    complete: function ()
    {
        //on complete event     
    },
    progress: function (evt)
    {
        //progress event    
    },
    ///Ajax events
    beforeSend: function (e) {
        //before event  
    },
    success: function (e) {
        //success event
    },
    error: function (e) {
        //errorHandler
    },
    ///Form data
    data: formData,
    ///Options to tell JQuery not to process data or worry about content-type
    cache: false,
    contentType: false,
    processData: false
});
///end AJAX request

var fd = new FormData();
fd.append(file.name,file);