javascript ExtJs 4 回调
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ExtJs 4 callbacks
提问by leonardorame
I had a hard time trying to find out why my assignments where lost, and found that callbacks scope was different than I thought.
我很难找出我的作业丢失的原因，并发现回调范围与我想象的不同。
What I did was to create a variable in a controller, then trying to pass a callback to a window created by the controller, then, on an event on that window, call-back a function in the controller.
我所做的是在控制器中创建一个变量，然后尝试将回调传递给控制器创建的窗口，然后在该窗口上的事件上回调控制器中的函数。
For example, in my controller I have:
例如，在我的控制器中，我有：
callWindow: function(){
var myWin = Ext.Create('MyApp.view.myWin', {doSomething: this.doSomething});
},
doSomething: function(data){
this.myData = data;
},
useTheData: function(){
console.log(this.myData);
}
In myWin's controller, I have an even handler that calls doSomething this way:
在 myWin 的控制器中，我有一个偶数处理程序，它以这种方式调用 doSomething：
onBtnClick: function(button){
var win = button.up('window');
var data = {id: 1, name: "John"}; // please, don't pay attention to this, it's a record I'm passing to the caller.
win.doSomething(data);
}
As you can see, in "doSomething" function, I'm assigning the controller var myData, with the value passed by the window's controller. Initially I thought the scope of "doSomething" was the caller controller, but it's the window's controller, that's why useTheData gives an error saying this.myData is null.
如您所见，在“doSomething”函数中，我使用窗口控制器传递的值分配控制器 var myData。最初我认为“doSomething”的范围是调用者控制器，但它是窗口的控制器，这就是为什么 useTheData 给出一个错误，说 this.myData 为空。
I've solved the problem by passing a new parameter named "caller: this", and in doSomething, receiving that parameter, and using it instead of "this".
我通过传递一个名为“caller: this”的新参数解决了这个问题，在 doSomething 中，接收该参数，并使用它而不是“this”。
The question is, is there a easy (with less steps) way to do this?.
问题是，是否有一种简单（步骤更少）的方法来做到这一点？
回答by sra
You need to apply a scope for your callback to the window and use Ext.callback
您需要将回调范围应用于窗口并使用Ext.callback
callWindow: function(){
var myWin = Ext.Create('MyApp.view.myWin', {doSomething: this.doSomething, scope: this});
},
onBtnClick: function(button){
var win = button.up('window');
var data = {id: 1, name: "John"}; // please, don't pay attention to this, it's a record I'm passing to the caller.
Ext.callback(win.doSomething, win.scope, [data]);
}
This is one way, your solution is another and there are even more.
这是一种方式，您的解决方案是另一种方式，还有更多。
