角度ng重复表达式作为变量 [英] angular ng-repeat expressions as variables

问题描述

我正在尝试这样做：

<ul>
    <li ng-repeat="{{myRepeatExpression}}">{{row.name}}</li>
</ul>

但是因为 ng-repeat 逻辑是在指令的编译状态下，它将 {{myRepeatExpression}} 视为常规字符串而不是变量。这显然不起作用。

But because the ng-repeat logic is in the compile state of the directive it treats the {{myRepeatExpression}} as a normal string instead of a variable. Which doesn't work, obviously.

是否有任何解决方法？

Is there any workaround for that?

推荐答案

您只能使用 ng-repeat 内插值。
现在为了创建一个动态可重复的列表，你可以尝试：

You can only use and expression with ng-repeat and not an interpolated value. Now in order to create a dynamic repeatable list you can try either:

1. 使用一个函数，在 ng-repeat - 这可能更昂贵，因为角度需要首先调用该函数，然后确定在执行 $时集合是否已更改对触发更改的范围的特定变量的消息循环


2. $ watch 的列表 - 可能更有效率，但如果您的动态列表依赖于多个变量，它可以变得更冗长，并可能导致潜在的错误，忘记添加一个新的 $ watch 需要新的变量

1. using a function that returns the list dynamically in the ng-repeat - this is potentially more expensive since angular needs to call the function first then determine if the collection has changed when doing a $digest cycle
2. $watch for a particular variable on the scope that trigger a change of the list - potentially more efficient but if your dynamic list depends on more than one variable it can get more verbose and can lead to potential bugs from forgetting to add a new $watch when a new variable is required

演示空格

JS：

app.controller('MainCtrl', function($scope) {
  var values1 = [{name:'First'}, {name:'Second'}];
  var values2 = [{name:'Third'}, {name:'Fourth'}, {name:'Fifth'}];

  //1. function way
  $scope.getValues = function(id) {
    if(id === 1) {
      return values1;
    }
    if(id === 2) {
      return values2;
    }
  }

  //2. watch way
  $scope.values = undefined;
  $scope.$watch('id', function(newVal) {
    $scope.values = $scope.getValues(newVal);
  });
});

HTML：

<!-- Here we pass the required value directly to the function -->
<!-- this is not mandatory as you can use other scope variables and/or private variables -->
<ul>
  <li ng-repeat="v in getValues(id)">{{v.name}}</li>
</ul>
<!-- Nothing special here, plain old ng-repeat -->
<ul>
  <li ng-repeat="v in values">{{v.name}}</li>
</ul>

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