AngularJS 使用ngOption实现下拉列表

最近使用到了ngOption实现下拉选择列表，由于需要实现分组等功能，百度了下没有太好的文章，就百度到一篇英文的帖子，按照其中的代码很顺利的搞定了。

本篇根据文中代码，详细讲述下如何实现下拉列表

更多内容参考：AngularJS知识总结

下拉列表的简单使用

ng-option指令使用很简单，只需要绑定两个属性：

一个是ng-model用于获取选定的值；

另一个是ng-options用于确定下拉列表的元素数组。

<select ng-model="engineer.currentActivity" class="form-control" ng-options="act for act in activities"></select>

上面这条语句就是把选择的值与engineer.currentActivity进行双向数据绑定，然后列表中的选项是activities中的每一个值。数据如下：

$scope.engineer = {                  name: "Dani",                  currentActivity: "Fixing bugs"              };                         $scope.activities =              [                  "Writing code",                  "Testing code",                  "Fixing bugs",                  "Dancing"              ];

运行结果如：

为了美观一点，这里引用了bootstrap。

 <html ng-app="myApp">  <head>      <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />      <script src="http://apps.bdimg.com/libs/angular.js/1.2.16/angular.min.js"></script>      <link rel="stylesheet" href="http://apps.bdimg.com/libs/bootstrap/3.3.0/css/bootstrap.min.css">        <script src="http://apps.bdimg.com/libs/jquery/2.1.1/jquery.min.js"></script>      <script src="http://apps.bdimg.com/libs/bootstrap/3.3.0/js/bootstrap.min.js"></script>  </head>  <body>      <div ng-controller="EngineeringController" class="container">          <div class="col-md-12">              {{engineer.name}} is currently: {{ engineer.currentActivity}}          </div>          <div class="col-md-4">              <label for="name">Choose a new activity:</label>              <select ng-model="engineer.currentActivity" class="form-control"                      ng-options="act for act in activities">                             </select>          </div>      </div>      <script type="text/javascript">           var myAppModule = angular.module("myApp",[]);           myAppModule.controller("EngineeringController",["$scope",function($scope){              $scope.engineer = {                  name: "Dani",                  currentActivity: "Fixing bugs"              };                         $scope.activities =              [                  "Writing code",                  "Testing code",                  "Fixing bugs",                  "Dancing"              ];           }]);      </script>  </body>  </html>    View Code

复杂对象，自定义列表名称

有的时候下拉列表并不是单纯的字符串数组，可能是json对象，例如：

$scope.activities =               [                   { id: 1, type: "Work" , name: "Writing code" },                   { id: 2, type: "Work" , name: "Testing code" },                   { id: 3, type: "Work" , name: "Fixing bugs" },                   { id: 4, type: "Play" , name: "Dancing" }               ];

这个时候，绑定的数据就必须是与这里面的格式相同的数据，比如直接复制其中一条：

$scope.engineer = {                   name: "Dani" ,                   currentActivity: {                       id: 3,                       type: "Work" ,                       name: "Fixing bugs"                   }               };

当然也可以直接指定成：

$scope.engineer = {currentActivity:activities[3]}

然后在指令中可以循环列表拼接处下拉框的名称

<select           ng-model = "engineer.currentActivity"          class="form-control"          ng-options = "a.name +' (' + a.type + ')' for a in activities" >                 </select >

运行效果如：

全部的代码如下：

 <html ng-app="myApp">  <head>      <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />      <script src="http://apps.bdimg.com/libs/angular.js/1.2.16/angular.min.js"></script>      <link rel="stylesheet" href="http://apps.bdimg.com/libs/bootstrap/3.3.0/css/bootstrap.min.css">        <script src="http://apps.bdimg.com/libs/jquery/2.1.1/jquery.min.js"></script>      <script src="http://apps.bdimg.com/libs/bootstrap/3.3.0/js/bootstrap.min.js"></script>  </head>  <body>      <div ng-controller="EngineeringController" class="container">          <div class="col-md-12">          {{engineer.name}} is currently: {{ engineer.currentActivity}}          </div>          <div class="col-md-4">              <label for="name">Choose a new activity:</label>                          <select               ng-model = "engineer.currentActivity"              class="form-control"              ng-options = "a.name +' (' + a.type + ')' for a in activities" >                             </select >           </div>      </div>      <script type="text/javascript">           var myAppModule = angular.module("myApp",[]);           myAppModule.controller("EngineeringController",["$scope",function($scope){              $scope.engineer = {                   name: "Dani" ,                   currentActivity: {                       id: 3,                       type: "Work" ,                       name: "Fixing bugs"                   }               };                          $scope.activities =               [                   { id: 1, type: "Work" , name: "Writing code" },                   { id: 2, type: "Work" , name: "Testing code" },                   { id: 3, type: "Work" , name: "Fixing bugs" },                   { id: 4, type: "Play" , name: "Dancing" }               ];           }]);      </script>  </body>  </html>    View Code

实现下拉列表的分组

其实分组与前面的例子很像，只要把空间中的ng-options的值换成下面：

<select ng-model = "engineer.currentActivity"          class="form-control"          ng-options = "a.name group by a.type for a in activities" >                 </select >

添加 group by 就会按照后面的值进行分组

全部代码：

 <html ng-app="myApp">  <head>      <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />      <script src="http://apps.bdimg.com/libs/angular.js/1.2.16/angular.min.js"></script>      <link rel="stylesheet" href="http://apps.bdimg.com/libs/bootstrap/3.3.0/css/bootstrap.min.css">        <script src="http://apps.bdimg.com/libs/jquery/2.1.1/jquery.min.js"></script>      <script src="http://apps.bdimg.com/libs/bootstrap/3.3.0/js/bootstrap.min.js"></script>  </head>  <body>      <div ng-controller="EngineeringController" class="container">          <div class="col-md-12">          {{engineer.name}} is currently: {{ engineer.currentActivity}}          </div>          <div class="col-md-4">              <label for="name">Choose a new activity:</label>                          <!-- <select               ng-model = "engineer.currentActivity"              class="form-control"              ng-options = "a.name +' (' + a.type + ')' for a in activities" >                             </select >  -->              <select ng-model = "engineer.currentActivity"                      class="form-control"                      ng-options = "a.name group by a.type for a in activities" >                             </select >           </div>      </div>      <script type="text/javascript">           var myAppModule = angular.module("myApp",[]);           myAppModule.controller("EngineeringController",["$scope",function($scope){              $scope.engineer = {                   name: "Dani" ,                   currentActivity: {                       id: 3,                       type: "Work" ,                       name: "Fixing bugs"                   }               };                          $scope.activities =               [                   { id: 1, type: "Work" , name: "Writing code" },                   { id: 2, type: "Work" , name: "Testing code" },                   { id: 3, type: "Work" , name: "Fixing bugs" },                   { id: 4, type: "Play" , name: "Dancing" }               ];           }]);      </script>  </body>  </html>    View Code

按照id进行标识

由于之前的ng-model相当于初始的时候给设定了一个值。当你选择一个下拉列表选项的时候，就会覆盖掉这个初始值。

所以更多的时候会使用一个id进行标识，这样在初始化赋值的时候，只需要设定一个id就可以了。

$scope.engineer = {                   currentActivityId: 3               };                          $scope.activities =               [                   { id: 1, type: "Work" , name: "Writing code" },                   { id: 2, type: "Work" , name: "Testing code" },                   { id: 3, type: "Work" , name: "Fixing bugs" },                   { id: 4, type: "Play" , name: "Dancing" }               ];

指令可以写成下面的格式

<select          ng-model = "engineer.currentActivityId"         class="form-control"         ng-options = "a.id as a.name group by a.type for a in activities" >                 </select >

通过 as 前面的值，就可以确定唯一的一个选项

全部代码如下：

 <html ng-app="myApp">  <head>      <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />      <script src="http://apps.bdimg.com/libs/angular.js/1.2.16/angular.min.js"></script>      <link rel="stylesheet" href="http://apps.bdimg.com/libs/bootstrap/3.3.0/css/bootstrap.min.css">        <script src="http://apps.bdimg.com/libs/jquery/2.1.1/jquery.min.js"></script>      <script src="http://apps.bdimg.com/libs/bootstrap/3.3.0/js/bootstrap.min.js"></script>  </head>  <body>      <div ng-controller="EngineeringController" class="container">          <div class="col-md-12">          current is: {{ engineer.currentActivityId}}          </div>          <div class="col-md-4">              <label for="name">Choose a new activity:</label>                          <select                   ng-model = "engineer.currentActivityId"                  class="form-control"                  ng-options = "a.id as a.name group by a.type for a in activities" >                             </select >           </div>      </div>      <script type="text/javascript">           var myAppModule = angular.module("myApp",[]);           myAppModule.controller("EngineeringController",["$scope",function($scope){              $scope.engineer = {                   currentActivityId: 3               };                          $scope.activities =               [                   { id: 1, type: "Work" , name: "Writing code" },                   { id: 2, type: "Work" , name: "Testing code" },                   { id: 3, type: "Work" , name: "Fixing bugs" },                   { id: 4, type: "Play" , name: "Dancing" }               ];           }]);      </script>  </body>  </html>    View Code