使用KnockoutJS和Simple Class Inheritance时失去对self的引用 [英] Lost reference to self when using KnockoutJS and Simple Class Inheritance

问题描述

我使用 John Resig的简单JavaScript继承来创建一个类可以继承。我也在使用KnockoutJS来计算可观察量。问题在于尝试将这两个概念结合起来。当我尝试在计算的observable中获得对self的引用时，我得到Window对象而不是预期的实际对象。这是一个快速代码示例：

I am using John Resig's "Simple JavaScript Inheritance" to create a class that can be inherited. I am also using KnockoutJS for computed observables. The problem comes in trying to combine these two concepts. When I try to gain a reference to self in the computed observable I get the "Window" object instead of the expected actual object. Here is a quick code sample:

window.mynamespace.myclass = Class.extend({
    init: function() {

    },
    someProperty: ko.observable(10),
    someComputedProperty: ko.computed(function() {
       return this.someProperty();  
    }, this)
});

不幸的是找不到this.someProperty（），因为'this'是对Window的引用。有什么想法或想法吗？

Unforunately this.someProperty() is unable to be found because 'this' is a reference to Window. Any thoughts or ideas?

推荐答案

您可以随时在 init 。在敲除自己的示例中，他们在构造函数中进行绑定。

You could always add them in the init. In knockout's own examples they do their binding in the constructor.

window.mynamespace.myclass = Class.extend({
    init: function() {
        this.someProperty = ko.observable(10);
        this.someComputedProperty = ko.computed(function() {
           return this.someProperty();  
        }, this);  
    }
});

或者捕获对的引用并忘记关于绑定：

Or capturing a reference to this and forgetting about binding:

window.mynamespace.myclass = Class.extend({
    init: function() {
        var self = this;
        self.someProperty = ko.observable(10);
        self.someComputedProperty = ko.computed(function() {
           return self.someProperty();  
        });  
    }
});

---

编辑：

演示你如何扩展课程：

---

To demonstrate how you'd extend the class:

window.mynamespace.myotherclass = window.mynamespace.myclass.extend({
    init: function() {
      // do anything myotherclass init, like another observable
      this.someOtherProperty = ko.observable(10);

      // incidentally you *can* have private variables with this pattern
      var imPrivate = 1;
      this.getImPrivate = function() {
        return imPrivate;
      };

      // then call super (maybe with arguments, maybe just passing them)
      this._super('foobar');
    }
});

这篇关于使用KnockoutJS和Simple Class Inheritance时失去对self的引用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！