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>

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>

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>

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>

参考

Using ngOptions in AngularJS:http://odetocode.com/blogs/scott/archive/2013/06/19/using-ngoptions-in-angularjs.aspx