删除并重新添加聚合物元素实例的正确方法是什么？

Question

Removing and re-adding a polymer element instance breaks the data bindings. 删除并重新添加聚合物元素实例会破坏数据绑定。 Calling prepareElement() reconnects everything, but is this the best way? 调用prepareElement（）可以重新连接所有内容，但这是最好的方法吗？

Given this HTML, using the click-counter example 给定此HTML，使用点击计数器示例

<body>           
  <click-counter id="click_counter_id" count="5"></click-counter>    
</body>

and the code 和代码

main() {
  Logger.root.level = Level.ALL;
  Logger.root.onRecord.listen((LogRecord rec) {   
    print('${rec.loggerName}: ${rec.level.name}: ${rec.time}: ${rec.message}');
  });

  initPolymer().run(() {

    Polymer.onReady.then((_) {            

      var elem = querySelector('#click_counter_id');
      var parent = elem.parent;

      elem.remove();         

      new Timer(new Duration(seconds:1), () {

        parent.children.add(elem);

        // This reconnects the bindings. Is it correct?
        (elem as PolymerElement).prepareElement();
      });
    });
  });            
}

everything seems ok. 一切似乎还好。 But then we get a warning logged: 但是随后我们收到一条警告记录：

polymer.events: FINE: event: [button].on-click => [click-counter].increment())
polymer.unbind: FINE: [click-counter] cancelUnbindAll
polymer.unbind: WARNING: [click-counter] already unbound, cannot cancel unbindAll
polymer.events: FINE: event: [button].on-click => [click-counter].increment())

Is there a better way to remove and re-add a polymer element instance? 是否有删除和重新添加聚合物元素实例的更好方法？

Answer 1

I have not tried it myself but it seems reasonable. 我自己还没有尝试过，但这似乎是合理的。 I hope the author doesn't mind coping his answer from Detached observables when re-using element. 我希望作者在重用元素时不介意从Detached observables中回答他。

Having looked into the polymer.js information bit I have found that there is a cancelUnbindAll function which must be called when the element is created or a preventDispose property set to true. 研究了polymer.js信息位后，我发现有一个cancelUnbindAll函数，在创建元素或将preventDispose属性设置为true时必须调用该函数。

For anyone that might need to do the same, in the Dart implementation you must call cancelUnbindAll in the leftView function after the super call, as follows: 对于可能需要执行此操作的任何人，在Dart实现中，必须在超级调用之后在leftView函数中调用cancelUnbindAll，如下所示：

void detached() {
    super.leftView();
    this.cancelUnbindAll(preventCascade: true);
}

Alternatively, you can simply override the preventDispose property in your custom element: 另外，您可以简单地在自定义元素中覆盖preventDispose属性：

bool get preventDispose => true;

EDIT 编辑

There is also a preventDispose see https://github.com/Polymer/polymer/issues/312 还有一个preventDispose参见https://github.com/Polymer/polymer/issues/312

删除并重新添加聚合物元素实例的正确方法是什么？

问题描述

1 个解决方案

解决方案1
2 已采纳 2014-03-18 17:14:54

EDIT 编辑

删除并重新添加聚合物元素实例的正确方法是什么？

问题描述

1 个解决方案

解决方案1 2 已采纳 2014-03-18 17:14:54

EDIT 编辑

解决方案1
2 已采纳 2014-03-18 17:14:54