Javascript AngularJS ng-repeat 处理空列表案例
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AngularJS ng-repeat handle empty list case
提问by Prinzhorn
I thought this would be a very common thing, but I couldn't find how to handle it in AngularJS. Let's say I have a list of events and want to output them with AngularJS, then that's pretty easy:
我认为这将是一件很常见的事情，但我找不到如何在 AngularJS 中处理它。假设我有一个事件列表并想用 AngularJS 输出它们，那么这很简单：
<ul>
<li ng-repeat="event in events">{{event.title}}</li>
</ul>
But how do I handle the case when the list is empty? I want to have a message box in place where the list is with something like "No events" or similar. The only thing that would come close is the ng-switchwith events.length(how do I check if empty when an object and not an array?), but is that really the only option I have?
但是当列表为空时我该如何处理呢？我想在列表中放置一个消息框，其中包含“无事件”或类似内容。唯一接近的是ng-switchwith events.length（当对象而不是数组时我如何检查是否为空？），但这真的是我唯一的选择吗？
回答by Artem Andreev
You can use ngShow.
您可以使用ngShow。
<li ng-show="!events.length">No events</li>
See example.
参见示例。
Or you can use ngHide
或者你可以使用ngHide
<li ng-hide="events.length">No events</li>
See example.
参见示例。
For object you can test Object.keys.
对于对象，您可以测试Object.keys。
回答by Konrad 'ktoso' Malawski
And if you want to use this with a filtered list here's a neat trick:
如果你想将它与过滤列表一起使用，这里有一个巧妙的技巧：
<ul>
<li ng-repeat="item in filteredItems = (items | filter:keyword)">
...
</li>
</ul>
<div ng-hide="filteredItems.length">No items found</div>
回答by Pylinux
With the newer versions of angularjs the correct answer to this question is to use ng-if:
对于较新版本的 angularjs，这个问题的正确答案是使用ng-if：
<ul>
<li ng-if="list.length === 0">( No items in this list yet! )</li>
<li ng-repeat="item in list">{{ item }}</li>
</ul>
This solution will not flicker when the list is about to download either because the list has to be defined and with a length of 0 for the message to display.
当列表即将下载时，此解决方案也不会闪烁，因为必须定义列表并且长度为 0 才能显示消息。
Here is a plunker to show it in use: http://plnkr.co/edit/in7ha1wTlpuVgamiOblS?p=preview
这是一个显示它在使用中的plunker：http://plnkr.co/edit/in7ha1wTlpuVgamiOblS?p=preview
Tip: You can also show a loading text or spinner:
提示：您还可以显示加载文本或微调器：
<li ng-if="!list">( Loading... )</li>
回答by Mortimer
You might want to check out the angular-ui directiveui-ifif you just want to remove the ulfrom the DOM when the list is empty:
如果您只想在列表为空时从 DOM 中删除 ，您可能需要查看angular-ui 指令：ui-iful
<ul ui-if="!!events.length">
<li ng-repeat="event in events">{{event.title}}</li>
</ul>
回答by Bernard
<ul>
<li ng-repeat="item in items | filter:keyword as filteredItems">
...
</li>
<li ng-if="filteredItems.length===0">
No items found
</li>
</ul>
This is similar to @Konrad 'ktoso' Malawski but slightly easier to remember.
这类似于@Konrad 'ktoso' Malawski，但稍微容易记住。
Tested with Angular 1.4
用 Angular 1.4 测试
回答by Miriam Salzer
Here's a different approach using CSS instead of JavaScript/AngularJS.
这是一种使用 CSS 而不是 JavaScript/AngularJS 的不同方法。
CSS:
CSS：
.emptymsg {
display: list-item;
}
li + .emptymsg {
display: none;
}
Markup:
标记：
<ul>
<li ng-repeat="item in filteredItems"> ... </li>
<li class="emptymsg">No items found</li>
</ul>
If the list is empty, <li ng-repeat="item in filteredItems">, etc. will get commented out and will become a comment instead of a li element.
如果列表为空，<li ng-repeat="item infilteredItems"> 等将被注释掉并成为注释而不是 li 元素。
回答by LukitaBrands
You can use this ng-switch:
你可以使用这个 ng-switch：
<div ng-app ng-controller="friendsCtrl">
<label>Search: </label><input ng-model="searchText" type="text">
<div ng-init="filtered = (friends | filter:searchText)">
<h3>'Found '{{(friends | filter:searchText).length}} friends</h3>
<div ng-switch="(friends | filter:searchText).length">
<span class="ng-empty" ng-switch-when="0">No friends</span>
<table ng-switch-default>
<thead>
<tr>
<th>Name</th>
<th>Phone</th>
</tr>
</thead>
<tbody>
<tr ng-repeat="friend in friends | filter:searchText">
<td>{{friend.name}}</td>
<td>{{friend.phone}}</td>
</tr>
</tbody>
</table>
</div>
回答by Damian Czapiewski
You can use askeyword to refer a collection under a ng-repeatelement:
您可以使用as关键字来引用ng-repeat元素下的集合：
<table>
<tr ng-repeat="task in tasks | filter:category | filter:query as res">
<td>{{task.id}}</td>
<td>{{task.description}}</td>
</tr>
<tr ng-if="res.length === 0">
<td colspan="2">no results</td>
</tr>
</table>
回答by Ezequiel García
i usually use ng-show
我通常使用 ng-show
<li ng-show="variable.length"></li>
where variable you define for example
例如，您定义的变量
<div class="list-group-item" ng-repeat="product in store.products">
<li ng-show="product.length">show something</li>
</div>
回答by pejman
you can use ng-if because this is not render in html page and you dont see your html tag in inspect...
您可以使用 ng-if，因为这不会在 html 页面中呈现，并且您在检查中看不到 html 标签...
<ul ng-repeat="item in items" ng-if="items.length > 0">
<li>{{item}}<li>
</ul>
<div class="alert alert-info">there is no items!</div>
