Dart:@observable的getters [英] Dart: @observable of getters
问题描述
当我绑定隐式getter / setter对'name'时,它会更新
但是显式的getter'fullname'在HTML中没有更新。有一种方法来做这个工作(基本上,元素绑定中的'fullname'也应该更新)。也许我缺少一个setter,但后来setter在这里没有意义...
很简单的例子来证明:
test-element.html
< ; link rel =importhref =../../ packages / polymer / polymer.html>
< polymer-element name =test-element>
< template>
< input value ={{ds.name}}>
< div> {{ds.name}}< / div>
< div> {{ds.fullname}}< / div>
< / template>
< script type =application / dartsrc =test1.dart>< / script>
< / polymer-element>
test-element.dart
import'package:polymer / polymer.dart';
import'package:popoli / sysmaster-settings.dart';
@CustomTag('test-element')
class TestElement extends PolymerElement {
@observable VerySimpleTest ds;
TestElement.created():super.created(){
ds = new VerySimpleTest().. name ='Peter';
}
}
ds.dart
class VerySimpleTest extends Observable {
@observable String name ='';
@observable String get fullname => 'test:$ name';
VerySimpleTest():super();
}
一个值已改变getter依赖。
字符串集name(String val){
name = notifyPropertyChange(#fullname,name,val);
}
或者这也应该工作
@ComputedProperty('Test:$ name')String get fullname => 'test:$ name';
查看 http://japhr.blogspot.co.at/2014/08/the-polymerdart-computedproperty.html 了解更多详情。
I am trying to understand how observable getters work when they use other class instance properties:
When I bind the implicit getter/setter pair 'name' it updates in the input and in the div and everything is synced nicely.
However the explicit getter 'fullname' is not updating in the HTML. Is there a way to make that work (basically the 'fullname' in the element binding should update as well)?? Maybe I am missing a setter, but then again setter does not make sense here...
Very simple example to demonstrate:
test-element.html
<link rel="import" href="../../packages/polymer/polymer.html">
<polymer-element name="test-element">
<template>
<input value="{{ds.name}}">
<div>{{ds.name}}</div>
<div>{{ds.fullname}}</div>
</template>
<script type="application/dart" src="test1.dart"></script>
</polymer-element>
test-element.dart
import 'package:polymer/polymer.dart';
import 'package:popoli/sysmaster-settings.dart';
@CustomTag('test-element')
class TestElement extends PolymerElement {
@observable VerySimpleTest ds;
TestElement.created() : super.created() {
ds = new VerySimpleTest()..name = 'Peter';
}
}
ds.dart
class VerySimpleTest extends Observable {
@observable String name = '';
@observable String get fullname => 'Test: $name';
VerySimpleTest() : super();
}
You need to notify Polymer that a value has changed the getter depends on.
String set name(String val) {
name = notifyPropertyChange(#fullname, name, val);
}
or this should work too
@ComputedProperty('Test: $name') String get fullname => 'Test: $name';
See http://japhr.blogspot.co.at/2014/08/the-polymerdart-computedproperty.html for more details.
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