内回调时使用此jQuery访问对象上下文

问题描述：

让我们假设我定义了以下对象:

Let us presume I have the following object defined:

var myObj = function(){
     this.hello = "Hello,";
}

myObj.prototype.sayHello = function(){
     var persons = {"Jim", "Joe", "Doe","John"};
     $.each(persons, function(i, person){
       console.log(this.hello + person);
  }
}

问题是$ .each里面是人，但是我想访问obj属性hello.

Problem is that inside $.each this refers to person but I would like to access the obj property hello.

我能找到的唯一解决方案是在sayHello函数中声明类似

The only solution which i could find was declaring in sayHello function something like

var _this = this;

然后在$ .each中，我将使用类似

and then in $.each i would use something like

console.log(_this.hello + person);

但是不幸的是，这不是很好的代码.还有另一种方法可以优雅地解决此问题吗?

But unfortunately, this is not very good code. Is there another way to resolve this problem elegantly ?

答

这似乎不是一个糟糕的解决方案...也许您会对使用Function.bind感兴趣(请参阅

That doesn't seem to be a bad solution... Perhaps you would be more interested in using Function.bind (see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Function/bind#Compatibility for compatibility), but that leads to counter-performance...

var myObj = function(){
     this.hello = "Hello,";
}

myObj.prototype.sayHello = function(){
     var persons = ["Jim", "Joe", "Doe","John"];
     $.each(persons, function(i, person){
       console.log(this.hello + person);
     }.bind(this) );
}

另一种解决方案是声明一个变量并将其值设置为this.hello，如下所示:

Another solution is to declare a variable and set its value to this.hello, like this :

var myObj = function(){
     this.hello = "Hello,";
}

myObj.prototype.sayHello = function(){
     var persons = ["Jim", "Joe", "Doe","John"], 
         hello = this.hello;
     $.each(persons, function(i, person){
       console.log(hello + person);
     });
}

内回调时使用此jQuery访问对象上下文

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