[MVC]使用Ajax.BeginForm取得檔案欄位

form裡面一定要加入enctype = "multipart/form-data" Controller才會取得二進位制資料

@using (Ajax.BeginForm("FileUpload", "xxx", null, new AjaxOptions { HttpMethod = "Post",               OnSuccess = "" }, new{  @enctype = "multipart/form-data" }))
{
   <input type="file" name="files" class="form-control">
}

[Authorize]
[HttpPost]
public ActionResult FileUpload(FormCollection form, IEnumerable<HttpPostedFileBase> files)
{

}