win8: WinJS的面向对象 WinJS.Class

官方文档：http://msdn.microsoft.com/en-us/library/windows/apps/br229776.aspx

WinJS.Class.define 类定义

var object = WinJS.Class.define(constructor, instanceMembers, staticMembers);

三个参数是：构造函数，实例成员集合，静态成员集合。e.g.

var Robot = WinJS.Class.define( function(name) {
    this.name = name;
}, 
{ modelName: "" }, 
{ harmsHumans: false });

var myRobot = new Robot("Mickey");

myRobot.modelName = "4500";
Robot.harmsHumans = false;

对应的js代码是：

function Robot(name) {
    this.name = name;
}

Robot.prototype.modelName = '4500';
Robot.harmsHumans = false;

在JS中用 Object.defineProperty 定义modelName GET/SET时我们需要这么做：

Object.defineProperty(Robot.prototype, "modelName", {
    get: function () { this.computeModelName(); }
});

但在WinJS中：

var Robot = WinJS.Class.define(
    function (name) { this.name = name; },
    {
        modelName: { get: function () { return this.computeModelName(); } }
    }
);

 

WinJS.Class.derive 继承

 

var object = WinJS.Class.derive(baseClass, constructor, instanceMembers, staticMembers);

 

它通过调用Object.create 使用baseClass 的prototype 构造派生对象。

var SpaceRobot = WinJS.Class.derive(Robot, function (name) {
    this.name = name;
},
{ airSupply: "" },
{ saveSelf: true });

var mySpaceRobot = new SpaceRobot("Myra");
mySpaceRobot.airSupply = "oxygen";
var save = SpaceRobot.saveSelf;

WinJS.Class.mix 混合类

var object = WinJS.Class.mix(constructor);

WinJS.Namespace.define("Robotics", {
    Robot: WinJS.Class.define( function(name) {
        this.name = name;
        }, 
        { name: name }, 
        { harmsHumans: false, obeysOrders: true })
    }); 

var Movable = {
    goForward: function () {
        document.getElementById("div").innerText = "go forward";
    },
    goBack: function () {
        document.getElementById("div").innerText = "go back";
    },
    turnRight: function () {
        document.getElementById("div").innerText = "turn right";
    },
    turnLeft: function () {
        document.getElementById("div").innerText = "turn left";
    };

WinJS.Class.mix(Robotics.Robot, Movable);

var myRobot = new Robotics.Robot("Mickey");

myRobot.goBack();

当对象与WinJS.Utilities.eventMixin 等混合时，可以获取事件监听的功能等......

More info about mix , Check:http://msdn.microsoft.com/en-us/library/windows/apps/hh967789.aspx