angularjs - 使用 AngularJS 从选择选项中删除空白选项

Question

我是 AngularJS 新手。我查了很多资料，还是没有解决我的问题。

我第一次在选择框中得到一个空白选项。

这是我的 HTML 代码

<div ng-app="MyApp1">
    <div ng-controller="MyController">
        <input type="text" ng-model="feed.name" placeholder="Name" />
        <select ng-model="feed.config">
            <option ng-repeat="template in configs">{{template.name}}</option>
        </select>
    </div>
</div>

JS

var MyApp=angular.module('MyApp1',[])
MyApp.controller('MyController', function($scope) {
    $scope.feed = {};

      //Configuration
      $scope.configs = [
                                 {'name': 'Config 1',
                                  'value': 'config1'},
                                 {'name': 'Config 2',
                                  'value': 'config2'},
                                 {'name': 'Config 3',
                                  'value': 'config3'}
                               ];
      //Setting first option as selected in configuration select
      $scope.feed.config = $scope.configs[0].value;
});

但是好像不行。我怎样才能解决这个问题？这是JSFiddle Demo

Answer 1

供引用:Why does angularjs include an empty option in select ？

The empty option is generated when a value referenced by ng-model doesn't exist in a set of options passed to ng-options. This happens to prevent accidental model selection: AngularJS can see that the initial model is either undefined or not in the set of options and don't want to decide model value on its own.

In short: the empty option means that no valid model is selected (by valid I mean: from the set of options). You need to select a valid model value to get rid of this empty option.

像这样更改你的代码

var MyApp=angular.module('MyApp1',[])
MyApp.controller('MyController', function($scope) {
  $scope.feed = {};

  //Configuration
  $scope.feed.configs = [
    {'name': 'Config 1',
     'value': 'config1'},
    {'name': 'Config 2',
     'value': 'config2'},
    {'name': 'Config 3',
     'value': 'config3'}
  ];
  //Setting first option as selected in configuration select
  $scope.feed.config = $scope.feed.configs[0].value;
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div ng-app="MyApp1">
  <div ng-controller="MyController">
    <input type="text" ng-model="feed.name" placeholder="Name" />
    <!-- <select ng-model="feed.config">
<option ng-repeat="template in configs">{{template.name}}</option>
</select> -->
    <select ng-model="feed.config" ng-options="template.value as template.name for template in feed.configs">
    </select>
  </div>
</div>

Working JSFiddle Demo

更新(2015 年 12 月 31 日)

如果您不想设置默认值并希望删除空白选项，

<select ng-model="feed.config" ng-options="template.value as template.name for template in feed.configs">
      <option value="" selected="selected">Choose</option>
</select>

并且在JS中不需要初始化值。

$scope.feed.config = $scope.feed.configs[0].value;