Ember 组件中的共享状态 [英] Shared state in Ember component
问题描述
我试图用 append 小部件作为 Emberjs 组件构建一个简单的列表.
I was trying to build a simple list with append widget as an Emberjs component.
以下是我使用的代码:
HTML:
<!DOCTYPE html>
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/handlebars.js/1.0.0/handlebars.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/ember.js/1.0.0/ember.min.js"></script>
<meta charset=utf-8 />
<title>Ember Component example</title>
</head>
<body>
<script type="text/x-handlebars" id="components/appendable-list">
<h2> An appendable list </h2>
<ul>
{{#each item in myList}}
<li> {{item}} </li>
{{/each}}
</ul>
{{input type="text" value=newItem}}
<button {{action 'append'}}> Append Item </button>
</script>
<script type="text/x-handlebars">
{{appendable-list}}
{{appendable-list}}
</script>
</body>
</html>
Javascript:
Javascript:
App = Ember.Application.create();
App.AppendableListComponent = Ember.Component.extend({
theList: Ember.ArrayProxy.create({ content: [] }),
actions: {
appendItem: function(){
var newItem = this.get('newItem');
this.get('theList').pushObject(newItem);
}
}
});
在这种情况下，列表在两个实例之间共享(即，一个附加在另一个中)
In that case, the list is shared between the two instances (that is, appending in one appends in the other)
这是检查它的 JsBin:http://jsbin.com/arACoqa/7/edit?html,js,output
Here is the JsBin to check it out: http://jsbin.com/arACoqa/7/edit?html,js,output
如果我执行以下操作，它会起作用:
If I do the following, it works:
window.App = Ember.Application.create();
App.AppendableListComponent = Ember.Component.extend({
didInsertElement: function(){
this.set('myList', Ember.ArrayProxy.create({content: []}));
},
actions: {
append: function(){
var newItem = this.get('newItem');
this.get('myList').pushObject(newItem);
}
}
});
这是 JsBin:http://jsbin.com/arACoqa/8/edit?html,js,output
我做错了什么?提前致谢！
What am I doing wrong? Thanks in advance!
推荐答案
在声明组件后，每次在模板中使用它时都会创建一个新实例，最重要的是 init每次实例化新实例时也会调用钩子，因此拥有不同 myList 数组的最安全方法是使用组件 init 钩子来初始化数组，请尝试以下操作:
After you declare the component, each time you use it in your template a new instance will be created, and most importantly the init hook will also be called every time a new instance is instantiated, therefore the most secure way to have different myList arrays would be to use the component init hook, to initialize the array, so try the following:
App.AppendableListComponent = Ember.Component.extend({
myList: null,
init: function(){
this._super();
this.set('myList', Ember.ArrayProxy.create({content: []}));
},
actions: {
append: function(){
var newItem = this.get('newItem');
this.get('myList').pushObject(newItem);
}
}
});
同样重要的是在 init 中调用 this._super(); ，一切都会按预期工作.
Also important is to call this._super(); inside init and everything will work as expected.
请参阅此处获取有效的演示.
See here for a working demo.
希望有帮助.
这篇关于Ember 组件中的共享状态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！
