Javascript 如何在Windows 8模板中为项目添加新类？

我正试图用一个模板来设计这样的东西

但我不能在data.js中使用以下代码：

当我尝试在groupedItem.html中将新选项添加到此部件时：

结果是：

---

我怎样才能解决它？我没有在CSS中添加任何内容。首先，您需要在data.js文件中为所需的组指定数据项的数量。然后编辑GroupItemJS和css文件，如下所示。你会找到你想要的

我认为用网格api无法解决这个问题。但是你可以试试

var sampleItems = [
    { group: sampleGroups[0], importancia: "alta", title: "Item Title: 1", subtitle: "Item Subtitle: 1", description: itemDescription, content: itemContent, backgroundImage: lightGray },
    { group: sampleGroups[0], title: "Item Title: 2", subtitle: "Item Subtitle: 2", description: itemDescription, content: itemContent, backgroundImage: darkGray },
    { group: sampleGroups[0], title: "Item Title: 3", subtitle: "Item Subtitle: 3", description: itemDescription, content: itemContent, backgroundImage: mediumGray },
    { group: sampleGroups[0], title: "Item Title: 4", subtitle: "Item Subtitle: 4", description: itemDescription, content: itemContent, backgroundImage: darkGray },
    { group: sampleGroups[0], title: "Item Title: 5", subtitle: "Item Subtitle: 5", description: itemDescription, content: itemContent, backgroundImage: mediumGray }
];

<div class="itemtemplate" data-win-control="WinJS.Binding.Template">
    <div class="item" data-win-bind="className: importancia">
        <img class="item-image" src="#" data-win-bind="src: backgroundImage; alt: title" />
        <div class="item-overlay">
            <h4 class="item-title" data-win-bind="textContent: title" style="margin-left: 0px; margin-right: 291.08px;"></h4>
            <h6 class="item-subtitle win-type-ellipsis" data-win-bind="textContent: subtitle"></h6>
        </div>
    </div>
</div>