AngularJS：$观察 select 输入

Question

我知道我们可以使用 ng-change 来解决这个问题，但我想了解为什么 $watch 在 select 上不起作用。也许我做错了什么，但似乎我不是唯一一个为此苦苦挣扎的人。这是我的代码：

HTML:

<div class="list">
        <label class="item item-input item-select">
            <div class="input-label">
                Serveur
            </div>
            <select ng-model="server" ng-options="s as s.label for s in serverschoice">
            </select>
        </label>
    </div>

JS:

.controller('SettingsCtrl', function ($scope, $log, serverSelection) {

    //List of servers to connect to
    $scope.serverschoice = serverSelection.servers;
    $scope.server = serverSelection.server;
    $scope.$watch('server', function(NewValue, OldValue) {
        serverSelection.server = NewValue;
        $scope.url = serverSelection.url;
    }, true);

})

.service("serverSelection", function() {
    var self = this;

    self.servers = [
        { label: 'Production', value: 1, url: 'url1' },
        { label: 'Training', value: 2, url: 'url2' },
        { label: 'Local', value: 3, url: 'url2' }
    ];

    self.server = self.servers[1];
    console.log(self.server);
    self.url = self.server.url;

})

谢谢...

Answer 1

为了使其正常工作，您需要对代码进行大量更改，您需要将所有与服务器相关的信息放入一个名为 self.serverInfo 的对象中，该对象将包含有关 server 的信息 & servers 直接将其与范围变量绑定将根据 JavaScript 原型继承自动更新绑定。

HTML

<body ng-controller="SettingsCtrl">
  <div class="list">
    <label class="item item-input item-select">
      <div class="input-label">
        Server
      </div>
      {{serverInfo}}
      <select ng-model="serverInfo.server" 
      ng-options="s as s.label for s in serverInfo.servers">
      </select>
    </label>
  </div>
</body>

控制器

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

app.controller('SettingsCtrl', function ($scope, $log, serverSelection) {

    //List of servers to connect to
    $scope.serverInfo= serverSelection.serverInfo;
    $scope.$watch('serverInfo.server', function(NewValue, OldValue) {
        $scope.url = $scope.serverInfo.server.url;
    }, true);

})

app.service("serverSelection", function() {
    var self = this;
    self.serverInfo = {};
    self.serverInfo.servers = [
        { label: 'Production', value: 1, url: 'url1' },
        { label: 'Training', value: 2, url: 'url2' },
        { label: 'Local', value: 3, url: 'url2' }
    ];

    self.serverInfo.server = self.serverInfo.servers[1];
    console.log(self.server);
    self.serverInfo.url = self.serverInfo.server.url;

})

Working Plunkr

Answer 2

我接受@pankajparkar 的回答，但我想展示我的最终代码，因为事实上我已经使用@pankajparkar 提出的正确绑定，我不再需要 $watch。

HTML

    <div class="list">
        <label class="item item-input item-select">
            <div class="input-label">
                Serveur
            </div>
            <select ng-model="serverSelection.server" ng-options="s as s.label for s in serverSelection.servers">
            </select>
        </label>
    </div>
    <p>URL: {{serverSelection.server.url}}</p>

JS

.controller('SettingsCtrl', function ($scope, $log, serverSelection) {

    //List of servers to connect to
    $scope.serverSelection= serverSelection;

})


.service("serverSelection", function() {
    var self = this;

    self.servers = [
        { label: 'Production', value: 1, url: 'url0' },
        { label: 'Training', value: 2, url: 'url1' },
        { label: 'Local', value: 3, url: 'url2' }
    ];

    self.server = self.servers[1];

})

AngularJS：$观察 select 输入

AngularJS: $watch for a select input

javascript

angularjs

ionic-framework