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> 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：
{{engineer.name}} is currently: {{ engineer.currentActivity}}<select ng-model = "engineer.currentActivity" class="form-control" ng-options = "a.name +' (' + a.type + ')' for a in activities" > </select >
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：
{{engineer.name}} is currently: {{ engineer.currentActivity}}<select ng-model = "engineer.currentActivity" class="form-control" ng-options = "a.name group by a.type for a in activities" > </select >
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：
current is: {{ engineer.currentActivityId}}<select ng-model = "engineer.currentActivityId" class="form-control" ng-options = "a.id as a.name group by a.type for a in activities" > </select >
以上所述是小编给大家分享的AngularJS使用ngOption实现下拉列表的实例代码，希望对大家有所帮助。
