实施例

Question

我目前正在尝试创建一种表单，从两个相关的下拉菜单中选择选项。如果要更改上一个选项，则下一个选项上的数据也应根据上一个选项进行更改因此，我创建了一个小例子，您首先选择一个国家/地区。在此之后，您可以从该国家/地区选择一个城市数据存储在本地阵列中，稍后将通过服务获取。数据应保存在对象数组中，因为这是服务提供数据的方式，因此不需要进行任何转换。

在这里你可以看到我非常简单的代码，由于我不知道如何创建这样一个“通信”形式，这只是一个备用骨架。我希望你们能帮助我解决这类问题。

HTML

<body ng-app="AngularApp">
  <div ng-controller="MainCtrl as Main">
    <h1>{{Main.message}}</h1>
    country:
    <select name="country">
      <option></option>
    </select>
    <br/>city:
    <select name="city">
      <option></option>
    </select>
  </div>
  <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/1.7.2/jquery.min.js"></script>
</body>

App.js

var app = angular.module('AngularApp', []);

app.controller("MainCtrl", function() {
  var vm = this;

  vm.message = "Select your destination";
  vm.data = [
    { city: 'Berlin',         country: 'Germany' },
    { city: 'Hamburg',        country: 'Germany' },
    { city: 'Munich',         country: 'Germany' },
    { city: 'New York',       country: 'USA' },
    { city: 'Whashington DC', country: 'USA' },
    { city: 'Paris',          country: 'France' }
  ];
});

var app = angular.module('AngularApp', []);

app.controller("MainCtrl", function() {
  var vm = this;

  vm.message = "Select your destination";
  vm.data = [
    { city: 'Berlin',         country: 'Germany' },
    { city: 'Hamburg',        country: 'Germany' },
    { city: 'Munich',         country: 'Germany' },
    { city: 'New York',       country: 'USA' },
    { city: 'Whashington DC', country: 'USA' },
    { city: 'Paris',          country: 'France' }
  ];
});

<body ng-app="AngularApp">
  <div ng-controller="MainCtrl as Main">
    <h1>{{Main.message}}</h1>
    country:
    <select name="country">
      <option></option>
    </select>
    <br/>city:
    <select name="city">
      <option></option>
    </select>
  </div>
  <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/1.7.2/jquery.min.js"></script>
</body>

补充说明：
因此，如果您选择“德国”作为您所在的国家/地区，则在城市选择中，由于属性country，因此只能选择“柏林”，“汉堡”和“慕尼黑”。不会展示巴黎或纽约等其他城市。

修改如果每个默认选择一个国家/地区也会很好，这样就不会显示空的下拉列表。

Answer 1

您可以使用'angular-filter'模块显示唯一选项。

<select name="country" ng-model="country">
    <option ng-repeat="option in Main.data | unique: 'country'"
            value="{{option.country}}">{{option.country}}</option>
</select>

<select name="city" ng-model="city">
    <option ng-repeat="option in Main.data" ng-if="option.country == country"
            value="{{option.city}}">{{option.city}}</option>
</select>

实施例

我在表单中添加了一些Bootstrap类来清理它的表示。：）

var app = angular.module('AngularApp', ['angular.filter']);

app.controller("MainCtrl", function() {
  var vm = this;

  vm.message = "Select Your Destination";
  vm.data = [
    { city: 'Berlin',         country: 'Germany' },
    { city: 'Hamburg',        country: 'Germany' },
    { city: 'Munich',         country: 'Germany' },
    { city: 'New York',       country: 'USA' },
    { city: 'Whashington DC', country: 'USA' },
    { city: 'Paris',          country: 'France' }
  ];
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular-filter/0.5.11/angular-filter.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" />

<body ng-app="AngularApp">
  <div ng-controller="MainCtrl as Main" class="container">
    <h1>{{Main.message}}</h1>
    <form>
      <div class="form-group">
        <label>Country</label>
        <select name="country" ng-model="country" class="form-control">
          <option ng-repeat="option in Main.data | unique: 'country'" value="{{option.country}}">{{option.country}}</option>
        </select>
      </div>
      <div class="form-group">
        <label>City</label>
        <select name="city" ng-model="city" class="form-control">
          <option ng-repeat="option in Main.data" ng-if="option.country == country" value="{{option.city}}">{{option.city}}</option>
        </select>
      </div>
      <br />
      <button type="submit" class="btn btn-default">Submit</button>
    </form>
  </div>
</body>

Answer 2

HTML代码

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>Login</title>
  </head>
  <body ng-app="AngularApp">

  <div ng-controller="MainCtrl as Main">
    <h1>{{Main.message}}</h1>
    country:
    <select name="country" ng-model="cont" ng-init="cont = cont || 'Germany'">   
        <option ng-selected="$first" ng-repeat="con in Main.data | unique:'country'">{{con.country}}</option> 
    </select>
    <br/>
    city:
    <select name="city" ng-model="cit">
        <option ng-selected="$first" ng-repeat="ct in Main.data | filter:{country: cont}">{{ct.city}}</option>
    </select>
  </div>



  <script src="//ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js" type="text/javascript"></script>
  <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.2.25/angular.min.js" type="text/javascript"></script>
  <script src="app.js"></script>
  </body>
</html>

在app.js中创建一个名为“unique”的过滤器。所以你的app.js喜欢这个..

var app = angular.module('AngularApp', []);
app.controller("MainCtrl", function() {
    var vm = this;

    vm.message = 'select your destination';

    vm.data = [{city: 'Berlin', country: 'Germany'},
               {city: 'Hamburg', country: 'Germany'},
               {city: 'Munich', country: 'Germany'},
               {city: 'New York', country: 'USA'},
               {city: 'Whashington DC', country: 'USA'},
               {city: 'Paris', country: 'France'}
            ];
});
app.filter('unique', function() {
  return function (arr, field) {
    var o = {}, i, l = arr.length, r = [];
    for(i=0; i<l;i+=1) {
      o[arr[i][field]] = arr[i];
    }
    for(i in o) {
      r.push(o[i]);
    }
    return r;
  };
});

Answer 3

var app = angular.module('AngularApp', ['angular.filter']);

app.controller("MainCtrl", function() {
  var vm = this;

  vm.message = "Select Your Destination";
  vm.data = [
    { city: 'Berlin',         country: 'Germany' },
    { city: 'Hamburg',        country: 'Germany' },
    { city: 'Munich',         country: 'Germany' },
    { city: 'New York',       country: 'USA' },
    { city: 'Whashington DC', country: 'USA' },
    { city: 'Paris',          country: 'France' }
  ];
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular-filter/0.5.11/angular-filter.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" />

<body ng-app="AngularApp">
  <div ng-controller="MainCtrl as Main" class="container">
    <h1>{{Main.message}}</h1>
    <form>
      <div class="form-group">
        <label>Country</label>
        <select name="country" ng-model="country" class="form-control">
          <option value="" selected="selected">Choose one</option>
          <option ng-repeat="option in Main.data | unique: 'country'" value="{{option.country}}">{{option.country}}</option>
        </select>
      </div>
      <div class="form-group">
        <label>City</label>
        <select name="city" ng-model="city" class="form-control">
          <option value="" selected="selected">Choose one</option>
          <option ng-repeat="option in Main.data" ng-if="option.country == country" value="{{option.city}}">{{option.city}}</option>
        </select>
      </div>
      <br />
      <button type="submit" class="btn btn-default">Submit</button>
    </form>
  </div>
</body>

Answer 4

您可以使用以下HTML：

Country:
<select name="country" ng-model="country">
  <option ng-repeat="option in Main.data" value="{{option.country}}">{{option.country}}</option>
</select>

City:
<select name="city" ng-model="city">
  <option ng-repeat="option in Main.data" ng-if="option.country == country" value="{{option.city}}">{{option.city}}</option>
</select>

创建两个动态下拉菜单

HTML

App.js

4 个答案:

实施例