模板重复不适用于嵌套列表（Polymer.dart） [英] Template repeat not working for nested list (Polymer.dart)
问题描述
由于缺乏dart中的多维数组支持，我想到使用List。
Due to the lack of multi-dimensional array support in dart, I thought of using List.
Dart代码：
class MyModel extends Object with Observable {
@observable
List<List<int>> dataList = toObservable(new List<List<int>>());
}
void main() {
initPolymer().run(() {
Polymer.onReady.then((_) {
var template = querySelector("#bindValueTemplate") as AutoBindingElement;
var model = template.model = new MyModel();
for (int i=0; i<2;i++) {
List<int> in1 = new List<int>();
for (int j=0; j<2; j++) {
in1.add(j);
}
model.dataList.add(in1);
}
});
});
}
HTML档案（片段） >
HTML file (snippet):
<body fullbleed touch-action="auto">
<template id="bindValueTemplate" is="auto-binding-dart">
<div id="dynamic_area" layout horizontal>
<table template repeat="{{row in dataList}}">
<tr template repeat="{{col in row}}">
<td>{{col}}</td>
</tr>
</table>
</div>
</template>
</body>
我在控制台中遇到错误：
Uncaught Error: Error evaluating expression 'row': Class 'MyModel' has no instance getter 'row'.
NoSuchMethodError: method not found: 'row'
Receiver: Instance of 'MyModel'
Arguments: []
当在MyModel中使用getter添加'row'列表变量时，它会引发以下错误：
When I added a 'row' list variable in MyModel with a getter, it throws the following error :
未捕获错误：不支持的操作：无法评估in表达式
推荐答案
错误。 repeat子句应用于元素本身，而不是子元素。这解决了问题：
My understanding of template repeat was wrong. The repeat clause is to be applied for the the element itself, and not the children. This fixed the problem :
<body fullbleed touch-action="auto">
<template id="bindValueTemplate" is="auto-binding-dart">
<div id="dynamic_area" layout horizontal>
<table>
<tr template repeat="{{row in dataList}}">
<td template repeat="{{col in row}}">{{col}}</td>
</tr>
</table>
</div>
</template>
</body>
更新的dart代码：
class MyModel extends Object with Observable {
@observable
List<List<int>> dataList = toObservable(new List<List<int>>());
@observable
List<int> row = []; //I don't know why it works even without toObservable()
}
我将问题标记为已解决，因为我的具体问题已解决。但是问题仍然是如果我们实际想要重复表格元素！
I am marking the question as resolved because my specific problem was resolved. But the question still remains what if we actually want to repeat table elements !
这篇关于模板重复不适用于嵌套列表（Polymer.dart）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！
