在Angular.js中有条件地显示链接

Basically, I have this code in my template:

基本上,我在我的模板中有这个代码:

<tr ng-repeat="entry in tableEntries">

  <td ng-switch="entry.url == ''">
    <span ng-switch-when="false"><a href="{{entry.url}}">{{entry.school}}</a></span>
    <span ng-switch-when="true">{{entry.school}}</span>
  </td>

  ...
</tr>

As you can see I'm trying to display a clickable URL when entry.url is not empty and a plain text otherwise. It works fine, but it looks quite ugly. Is there a more elegant solution?

正如您所看到的,当entry.url不为空时我试图显示可点击的URL,否则显示纯文本。它工作正常,但看起来很难看。有更优雅的解决方案吗?

Another way I can think of doing it is using ng-if:

我能想到的另一种方法是使用ng-if:

<td>
  <span ng-if="entry.url != ''"><a href="{{entry.url}}">{{entry.school}}</a></span>
  <span ng-if="entry.url == ''">{{entry.school}}</span>
</td>

But then I would be repeating almost the same comparison twice, which looks even worse. How would you guys approach this?

但后来我会重复两次几乎相同的比较,看起来更糟。你们怎么会接近这个?

4 个解决方案

#1

You can try.

你可以试试。

<div ng-show="!link">hello</div> <div ng-show="!!link"><a href="{{link}}">hello</a></div>

你好

But the ngSwitch which you are using should be fine.

但是你使用的ngSwitch应该没问题。

#2

Use double negation, it cast into boolean thus !!entry.url will return true if string is not empty.

使用double negation,它会转换为boolean,因此如果string不为空,entry.url将返回true。

<td ng-switch="!!entry.url">
    <span ng-switch-when="true"><a href="{{entry.url}}">{{entry.school}}</a></span>
    <span ng-switch-when="false">{{entry.school}}</span>
</td>

A good read What is the !! (not not) operator in JavaScript? and Double negation (!!) in javascript - what is the purpose?

好读了什么!! (不是)JavaScript中的运算符?和javascript中的双重否定(!!) - 目的是什么?

#3

You can create a custom directive that hides the complexity:

您可以创建隐藏复杂性的自定义指令:

HTML

<tr ng-repeat="entry in tableEntries">
  <td>
    <link model="entry"></link>
  </td>
  ...
</tr>

app.directive('link', function() {
    return  {
        restrict: 'E', 
        scope: {
           model: '='
        },
        template: '<a ng-if="model.url != ''" href="{{model.url}}">{{model.school}}</a><span ng-if="model.url == ''"> {{ model.school }}</span>'

    }
});

#4

-1

I would recommend having an ng-class="{'className': whenEntryURLisWhatever}" in your td, and make it change the css styles accessed, e.g:

我建议你的td中有一个ng-class =“{'className':whenEntryURLisWhatever}”,并让它改变所访问的css样式,例如:

td span{ /*#normal styles#*/ }
.className span{ /*#styles in the case of added classname (when it is a link)#*/
           text-decoration: underline; 
           cursor:   pointer; 
}

Then just change what happens on ng-click within a function defined in your javascript code.

然后只需更改javascript代码中定义的函数中ng-click所发生的情况。

$scope.yourFunction = function(url){
    if(!!url){
        window.location = YourURL;
    }
}

This would cut down on code repetition, as your html could now be:

这会减少代码重复,因为你的html现在可能是:

 <tr ng-repeat="entry in tableEntries">
  <td ng-class="{'className': !!entry.url}">
    <span ng-click="yourFunction(entry.url)">{{entry.school}}</span> 
  </td>
  ...
</tr>

#1