javascript - 在嵌套的 json 数据 Angular js 的情况下，如何为 ng-options 设置默认值？

Question

我想通过使用 ng-init、ng-model 等为我的 ng-options 设置一个默认值。我正在使用可靠的下拉菜单。我的代码如下:

 <select id="country" ng-model="statessource" ng-disabled="!type2"  ng-options="country for (country, states) in countries" ng-change="GetSelectedCountry()">
                    <option value='' selected>Select Country</option>   
                </select>

<select id="state" ng-disabled="!statessource"  ng-model="citiessource"   ng-options="state for (state,city) in statessource"
                ng-change="GetSelectedState()"  >
                    <option value=''>Select State</option>
                </select>

像这样的一些数据:

$scope.countries = {
    'USA': {
        'IL': { 'CHICAGO': ['60633', '60646', '60653', '60656', '60607', '60632', '60643', '60652', '60620', '60612', '60661', '60624', '60634', '60601', '60827', '60644', '60631', '60630'] },
    }
}

我想在国家/地区下拉列表中设置默认值美国。我应该怎么做。请给我建议。

Answer 1

根据您发布的代码，您尚未在此处提供完整代码，您的代码中有太多错误。

定义另一个 $scope 变量，它选择了名为“USA”的默认对象。您可以按照以下方式执行此操作:

$scope.countries = {
    'USA': {
      'IL': {
        'CHICAGO': ['60633', '60646', '60653', '60656', '60607', '60632', '60643', '60652', '60620', '60612', '60661', '60624', '60634', '60601', '60827', '60644', '60631', '60630']
      },
    }
  }
  $scope.selected = $scope.countries["USA"]; // this needs to be added

您的 View 部分将如下所示:

 <select id="state" ng-disabled="!countries" ng-model="selected" 
    ng-options="state for (state,city) in countries" ng-change="GetSelectedState()">
    <option value=''>Select State</option>
  </select>

还有一个工作 Plunker

希望这会有所帮助。