我正在创建一个搜索页面，用户可以在其中使用第一个下拉列表中列出的预选搜索条件搜索数据。在下面的示例中，这些标准是"名字"、"国家"和"国籍"。
当用户选择"国家/地区"或"国籍"时，将显示第二个下拉列表以选择其中一个国家/地区/国籍。为了填充此下拉列表，我将 ng-options 与内部变量一起使用，该变量指向控制器中定义的字符串。
但是，当选择这两个选项之一并且您想要切换到另一个选项时，第二个下拉列表不会更新。ngOptions 中的值确实会在 HTML 中更新，只是下拉列表中的数据没有更新。
当您在两者之间选择"名字"时，没有问题。有谁知道我可以使用什么来更新第二个下拉列表中的值？
下面是我的代码和一个工作 plunker： http://plnkr.co/edit/LYpOdoLpgiMeHxlGzmub?p=preview
var myApp = angular.module('myApp', []);
myApp.controller("SomeController", function($scope) {
var vm = this;
vm.search = {id:0, criteria: {}, value: ''};
vm.referenceData = {
countries: [
{COUNTRY_ID:1, COUNTRY_NAME: 'UNITED KINGDOM'},
{COUNTRY_ID:2, COUNTRY_NAME: 'AUSTRALIA'},
{COUNTRY_ID:3, COUNTRY_NAME: 'SOUTH AFRICA'},
{COUNTRY_ID:4, COUNTRY_NAME: 'NETHERLANDS'},
],
nationalities: [
{NATIONALITY_ID: 1, NATIONALITY_NAME: "BRITISH"},
{NATIONALITY_ID: 2, NATIONALITY_NAME: "AUSTRALIAN"},
{NATIONALITY_ID: 3, NATIONALITY_NAME: "SOUTH AFRICAN"},
{NATIONALITY_ID: 4, NATIONALITY_NAME: "DUTCH"},
]
};
vm.criteriaList = [
{ name: 'First Name', key: 'FIRST_NAME'},
{ name: 'Country', key: 'COUNTRY_ID', options:'o.COUNTRY_ID as o.COUNTRY_NAME for o in ctrl.referenceData.countries' },
{ name: 'Nationality', key: 'NATIONALITY', options:'o.NATIONALITY_ID as o.NATIONALITY_NAME for o in ctrl.referenceData.nationalities' }
];
});<!DOCTYPE html>
<html>
<head>
<script data-require="angular.js@1.6.2" data-semver="1.6.2" src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.2/angular.js"></script>
<link rel="stylesheet" href="style.css" />
<script src="script.js"></script>
</head>
<body ng-app="myApp" ng-controller="SomeController as ctrl">
<p>Criteria:</p>
<select ng-model="search.criteria" ng-change="search.value = ''" ng-options="criteria as criteria.name for criteria in ctrl.criteriaList">
<option value="">- Select Criteria -</option>
</select>
<p>Value:</p>
<!-- TEXT INPUT -->
<input type="text" ng-model="search.value" placeholder="Search Value" ng-if="!search.criteria.options" />
<!-- DROPDOWN INPUT -->
<select ng-model="search.value" ng-if="search.criteria.options" ng-options="{{search.criteria.options}}"></select>
</html>这是一个简单的修复，你只需要一个变量，如果你每次切换时都可以弹出第二个下拉列表。dom 需要一些东西来强制它刷新，因为没有发生scope.$apply。
普伦克工作
试试这个：
var myApp = angular.module('myApp', []);
myApp.controller("SomeController", function($scope, $timeout) {
var vm = this;
vm.somVal = false; ///ADD THIS
vm.search = {id:0, criteria: {}, value: ''};
vm.triggerSomeVal = function(){ ///ADD THIS
vm.someVal = true;
$timeout(function(){vm.someVal = false}, 100)
};
vm.referenceData = {
countries: [
{COUNTRY_ID:1, COUNTRY_NAME: 'UNITED KINGDOM'},
{COUNTRY_ID:2, COUNTRY_NAME: 'AUSTRALIA'},
{COUNTRY_ID:3, COUNTRY_NAME: 'SOUTH AFRICA'},
{COUNTRY_ID:4, COUNTRY_NAME: 'NETHERLANDS'},
],
nationalities: [
{NATIONALITY_ID: 1, NATIONALITY_NAME: "BRITISH"},
{NATIONALITY_ID: 2, NATIONALITY_NAME: "AUSTRALIAN"},
{NATIONALITY_ID: 3, NATIONALITY_NAME: "SOUTH AFRICAN"},
{NATIONALITY_ID: 4, NATIONALITY_NAME: "DUTCH"},
]
};
vm.criteriaList = [
{ name: 'First Name', key: 'FIRST_NAME'},
{ name: 'Country', key: 'COUNTRY_ID', options:'o.COUNTRY_ID as o.COUNTRY_NAME for o in ctrl.referenceData.countries' },
{ name: 'Nationality', key: 'NATIONALITY', options:'o.NATIONALITY_ID as o.NATIONALITY_NAME for o in ctrl.referenceData.nationalities' }
];
});
<p>Criteria:</p>
<select ng-model="search.criteria" ng-change="search.value = ''; ctrl.triggerSomeVal()" ng-options="criteria as criteria.name for criteria in ctrl.criteriaList">
<option value="">- Select Criteria -</option>
</select>
<p>Value:</p>
<!-- TEXT INPUT -->
<input type="text" ng-model="search.value" placeholder="Search Value" ng-if="!search.criteria.options" />
<!-- DROPDOWN INPUT ADD !someVal-->
<select ng-model="search.value" ng-if="search.criteria.options && !ctrl.someVal" ng-options="{{search.criteria.options}}"></select>