我想在 Windows 8 RT(来自 BUILD 2011 的开发人员预览版)(使用 JavaScript)中的 ListView 中使用一个可观察的对象。
下面的代码似乎应该可以工作。它有一个简单的模板,用于在 HTML 中显示每个对象的标题和描述,以及 WinJS.UI.Listview 组件的基本使用。
我希望看到一个对象列表,但是当列表包含observables时,总是会看到“等待微调器” 。
在实验中,我注意到如果代码没有将整个列表(除了 3 个)转换为可观察对象,那么列表就会显示出来。从进行一些调试来看,它似乎与时间有关,并且 WinJS 框架计算错误并且无法完全呈现 ListView(因为某些对象“待处理”)由于某种原因(错误计算混乱发生在调用ScrollView 代码中的实现项)。如果我注释掉enableFirstChanceException
函数调用,它会在比较函数 itemChanged 中的两个对象(但我不知道它是否相关)时失败(不支持值参数中的循环引用)。
关于如何使用可观察对象进行这项工作的任何想法?
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=1024, height=768" />
<title>WinWebApp1</title>
<!-- WinJS references -->
<link rel="stylesheet" href="/winjs/css/ui-dark.css" />
<script type="text/javascript" src="/WinJS/js/base.js"></script>
<script type="text/javascript" src="/WinJS/js/ui.js"></script>
<script type="text/javascript" src="/WinJS/js/binding.js"></script>
<script type="text/javascript" src="/WinJS/js/controls.js"></script>
<script type="text/javascript" src="/WinJS/js/res.js"></script>
<script type="text/javascript" src="/WinJS/js/animations.js"></script>
<script type="text/javascript" src="/WinJS/js/uicollections.js"></script>
<script type="text/javascript" src="/WinJS/js/wwaapp.js"></script>
<!-- WinWebApp1 references -->
<link rel="stylesheet" href="/css/default.css" />
<script src="/js/default.js"></script>
</head>
<body>
<div id="itemTemplate" data-win-control="WinJS.Binding.Template" >
<div class="itemContainer">
<!-- Displays the "title" field. -->
<div class="itemTitle" data-win-bind="innerText: title">
</div>
<!-- Displays the "description" field. -->
<div class="itemDescription" data-win-bind="innerText: description">
</div>
</div>
</div>
<div data-win-control="WinJS.UI.ViewBox">
<div class="fixed-layout">
<div id="basicListView" data-win-control="WinJS.UI.ListView" data-win-options="{itemRenderer: itemTemplate}">
</div>
</div>
</div>
</body>
</html>
和 JavaScript:
(function () {
'use strict';
// Uncomment the following line to enable first chance exceptions.
//Debug.enableFirstChanceException(true);
var myData = [
{ title: "Banana", description: "Banana Frozen Yogurt"},
{ title: "Orange", description: "Orange Sherbet"},
{ title: "Vanilla", description: "Vanilla Ice Cream"},
{ title: "Mint", description: "Mint Gelato"},
{ title: "Strawberry", description: "Strawberry Sorbet"},
{ title: "Kiwi", description: "Kiwi Sorbet" }
];
// this works:
//var myDataSource = new WinJS.UI.ArrayDataSource(myData);
// this does not:
for (var i = 0; i < myData.length ; i++) {
myData[i] = WinJS.Binding.as(myData[i]);
}
var myDataSource = new WinJS.UI.ArrayDataSource(myData);
document.addEventListener("DOMContentLoaded", function (e) {
WinJS.UI.processAll()
.then(function () {
var basicListView = WinJS.UI.getControl(document.getElementById("basicListView"));
basicListView.dataSource = myDataSource;
// when the observable works correctly, this should work (and live change the list)
//setTimeout(function () {
// basicListView.refresh();
// myData[0].title = "Yellow Banana";
// myData[5].title = "Kiwisicle";
//}, 3000);
});
});
WinJS.Application.start();
})();