[英]Using Select Element in polymer dart component
嘗試在自定義元素中使用“選擇”組件,如下所示。 單擊按鈕有效,但是當在列表中選擇一個項目時,“ selected”和“ value”屬性不會更改,並且列表始終顯示所選的第一個元素。 綁定似乎從dart到html有效,但從html到dart無效。 請幫助!
<html>
<head>
<title>index</title>
<script src="packages/polymer/boot.js"></script>
</head>
<body>
<polymer-element name="my-element" extends="div">
<template >
<button on-click='bclick'>Add new fruit</button>
<select selectedIndex="{{selected}}" value="{{value}}">
<option template repeat="{{fruit in fruits}}">{{fruit}}</option>
</select>
<div>
You selected option {{selected}} with value-from-list
{{fruits[selected]}} and value-from-binding {{value}}
</div>
</template>
<script type="application/dart" src="polyselect.dart"></script>
</polymer-element>
<my-element></my-element>
<script type="application/dart">main() {}</script>
</body>
</html>
Dart文件如下:
import 'package:polymer/polymer.dart';
import 'dart:html';
@CustomTag('my-element')
class MyElement extends PolymerElement {
@observable int selected = 1; // Make sure this is not null.
// Set it to the default selection index.
List fruits = toObservable(['apples', 'bananas', 'pears', 'cherry', 'grapes']);
@observable String value = '';
void bclick(Event e) {
fruits.add("passion fruit");
}
}
我不得不混入ObservableMixin
類。
class MyElement extends PolymerElement with ObservableMixin
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