knockout.js：这孩子对象

Question

JS：

function Child() { 
    this.method = function() { 
     console.dir(this); // this should be 'p.child' <Child> since 
     //'method' called as a property of 'p.child' 
     // but when you call it from KO it's actually 'p' <Parent> 
    }; 
} 

function Parent() { 
    this.child = new Child(); 
} 
var p = new Parent(); 
ko.applyBindings(p); 

HTML：

<a href="#" data-bind="click: child.method">foo</a> 

它是错误或一个功能，我只是不明白？

Answer 1

你需要做到以下几点：

function Child() { 
    var self = this; 
    self.method = function() { 
     console.dir(self); // this should be 'p.child' <Child> since 
     //'method' called as a property of 'p.child' 
     // but when you call it from KO it's actually 'p' <Parent> 
    }; 
} 

function Parent() { 
    var self = this; 
    self.child = new Child(); 
} 
var p = new Parent(); 
ko.applyBindings(p); 

http://jsfiddle.net/ZuHMY/1/

请在这里看到的信息上self = this;

What underlies this JavaScript idiom: var self = this?

更新

这也回答是关于自己的问题，这在这里：

In knockout.js, why "this" is being assigned to "self"?

Answer 2

我不知道这是肯定的，但它可能是淘汰赛试图设置情境，让您可以在父工作从子功能和订阅中。

这JSFiddle演示了如何更改使用call(this)函数调用的上下文：

function Child() { 
    this.method = function() { 
     console.dir(this); 
    }; 
} 

function Parent() { 
    this.child = new Child(); 
} 
var p = new Parent(); 
p.child.method(); // child 
p.child.method.call(p); // parent