<input type="file" id="projectFile" name="projectFile"/>

$(function () {
        $('#projectFile').live('change', function () {
            $.ajaxFileUpload({
                    url: '/Management/SaveProjrctFile/',            //需要链接到服务器地址
                    secureuri: false,
                    fileElementId:'projectFile',                        //文件选择框的id属性
                    dataType:'json',                                    //服务器返回的格式，可以是json
                    success: function (data, status)            //相当于java中try语句块的用法
                    {

                        alert("OK" + data.name + "-" + data.path);

                    },
                    error: function (data, status, e)            //相当于java中catch语句块的用法
                    { 
                        alert( e );
                    }
                });
        });

    });

 public ActionResult SaveProjrctFile(HttpPostedFileBase projectFile)
        {
            HttpPostedFileBase file = projectFile;
            if (file != null)
            {
                try
                {
                    string filePath = AppDomain.CurrentDomain.BaseDirectory + "Content\\UploadFiles";
                    string fileName = Path.GetFileName(file.FileName);
                    string savePath = string.Format(@"{0}\{1}", filePath, fileName);
                    file.SaveAs(savePath);
                   
                    return Json(new { name = fileName });
                }
                catch (Exception ex)
                {
                    return Json(new { error = ex });
                }
            }
            else
            {
                return Json(new { error = "未选择文件"});
            }
        }