mvvm windows app DataBinding

前台html 绑定(view):
<div id="aa" data-win-bind="innerText:UserData.word" style="height: 40px; width: 100px; background: white; color: red"></div>

//js 实现 viewmodel
(function () {

    "use strict";



    WinJS.Binding.optimizeBindingReferences = true;



    var app = WinJS.Application;

    var activation = Windows.ApplicationModel.Activation;



    app.onactivated = function (args) {

        if (args.detail.kind === activation.ActivationKind.launch) {

            if (args.detail.previousExecutionState !== activation.ApplicationExecutionState.terminated) {

                WinJS.Namespace.define("ViewModel", WinJS.Binding.as({

                    UserData: {

                        word: 'aaaaaa',

                        wordLength: null

                    }

                }));



                document.querySelector("#btn").onclick = function () {



                    var text = document.querySelector('#text').value;

                    ViewModel.UserData.word = text; //text 就可以用model 去获取，这里用 输入框代替了

                }

            }

            args.setPromise(WinJS.UI.processAll().then(function () {



                return WinJS.Binding.processAll(document.querySelector('#aa'), ViewModel);



            }));

        }

    };

    app.start();

})();