在ng-options中使用条件选择默认值
[英]Select default value with condition in ng-options
问题描述
I have an angular app with the following array: 
我有一个带有以下数组的角度应用程序：
countries = [{"code": "ZA", "name": "South Africa"}, {"code": "CH", "name": "Switzerland"}]
with a Jade select as follow: 与玉选择如下：
select(ng-model='myCountry', ng-options='country.name for country in countries')
What I would like to do is to pre-select a country based on the code for example: 我想做的是根据代码预先选择一个国家，例如：
select(ng-model='myCountry', ng-options='country.name for country in countries', ng-selected='country.code=="CH"')
Obviously, this solution doesn't work as ng-selected is not intended to be used in a select but in an option tag. 显然，此解决方案无法正常工作，因为ng-selected并不打算在select中使用，而是在option标签中使用。
It is important for me to use a conditional selection and not a default index value like in the angularJS example . 对于我来说，重要的是使用条件选择而不是像angularJS示例中那样使用默认索引值。
2 个解决方案
解决方案1
1 2014-05-26 20:04:31
That is what ng-model is for. 那就是ng-model的目的。 I suggest you initialize myCountry in a controller. 我建议您在控制器中初始化myCountry。 Note that myCountry should ideally have the same format as countries (eg: {"code": "ZA", "name": "South Africa"} ). 请注意，理想情况下，myCountry应该与国家/地区具有相同的格式（例如： {"code": "ZA", "name": "South Africa"} ）。
Edit: I am adding an example from my own project: 编辑：我要从我自己的项目中添加一个示例：
<select class="small" data-ng-change="goToTask(current_task.id)" data-ng-model="current_task" data-ng-options="task.name for task in tasks track by task.id"></select>
In Controller: 在控制器中：
$scope.current_task = { id: $scope.myService.getCurrentTaskId() };
What is important here is that current_task is at minimum a hash containing the id key. 这里重要的是current_task至少是包含id键的哈希。
Edit2: I was thinking about the sorting problem with the track by. Edit2：我正在考虑跟踪依据的排序问题。 I think you can use select instead, eg: `ng-options="select country.code as country.name for country in countries". 我认为您可以使用select代替，例如：“ ng-options =“选择country.code作为国家/地区中国家/地区的国家/地区名称”。 I haven't tried it but from the angular docs, it should work. 我没有尝试过，但是从有角度的文档中，它应该可以工作。
解决方案2
1 已采纳 2014-05-26 20:20:47
From your sample above it looks like you should do this in your controller: 从上面的示例中，您似乎应该在控制器中执行此操作：
$scope.myCountry = $scope.countries.filter(function(c){ return c.code==="CH"})[0];
Like this: 像这样：
<script>
function MyCntrl($scope) {
$scope.countries = [{"code": "ZA", "name": "South Africa"}, {"code": "CH", "name": "Switzerland"}];
$scope.myCountry = $scope.countries.filter(function(c){ return c.code==="CH"})[0];
}
</script>
Or you could try building the select with and ngRepeat which seems to be closer to what you need, like this: 或者，您也可以尝试使用ngRepeat和ngRepeat构建选择，这似乎更接近您的需求，例如：
<body ng-app="">
<script>
function MyCntrl($scope) {
$scope.countries = [{"code": "ZA", "name": "South Africa"}, {"code": "CH", "name": "Switzerland"}];
}
</script>
<div ng-controller="MyCntrl">
<select ng-model="myCountry" >
<option ng-selected="c.code=='CH'" ng-repeat="c in countries">{{c.name}}</option>
</select><br>
{{myCountry |json}}
</body>
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