Angularjs选择值未定义

发布时间：2020-12-17 10:34:22 所属栏目：安全来源：网络整理

导读：现在我试图从select下拉列表获取值,但它返回undefined.事情在html级别,它按预期工作,这是我的代码： div class='subcontent' input id="me" type="radio" class='choosemethod' ng-model="paymentmethod" value="Y"label for="me" class='choosemethod'Me/la

现在我试图从select下拉列表获取值,但它返回undefined.事情在html级别,它按预期工作,这是我的代码：

<div class='subcontent'>            
  <input id="me" type="radio" class='choosemethod' ng-model="paymentmethod" value="Y"><label for="me" class='choosemethod'>Me</label>
  <input id="company" type="radio"  ng-model="paymentmethod" value="N" class='choosemethod'><label for="company" class='choosemethod'>My Company</label><br/>
  <span class='helptext'>Who makes payments to this account?</span><span class='help' style='margin-left:20px;width:20px;height:20px;'>help</span>
</div>

<div class='paymentmethods subcontent' ng-switch on="paymentmethod">
  <select ng-model='selectedmethod' ng-init="selectedmethod=Memethods[0]" id='methods' ng-switch-when='Y'>
    <option ng-repeat="method in Memethods" value="{{method}}">{{method}}</option>
  </select>

  <select ng-model='selectedmethod' ng-init="selectedmethod=companies[0]" ng-switch-when='N' style='float:left'>
    <option ng-repeat='companyoption in companies' value="{{companyoption}}">{{companyoption}}</option>
  </select>

  <div class='clear'></div>
  <label for ='methods'>Payment Method</label><span class='help' style='margin-left:20px;width:20px;height:20px;'>help</span>
</div>

在js中：

$scope.Memethods = ['Same as Card/Account Name','American Express','American Express Corp','Cash','Checking','MasterCard','My Visa','VISA'];
$scope.companies = ['Company Paid','MyAMEX'];

它在页面中显示正常,但是当我尝试获取值时,它显示未定义.任何的想法？

这是经典的“角点符号”问题.

Here is a working example

基本上,ng-switch会创建一个新范围,因此当select设置selectedmethod属性时,它会在新范围内执行,而不是按照您的预期执行控制器范围.一种解决方案是为模型创建父对象.

angular.module('app',[])
.controller('main',function($scope){
  $scope.selection = {};
  $scope.Memethods = ['Same as Card/Account Name','VISA'];
  $scope.companies = ['Company Paid','MyAMEX'];
})

并注意它在html中的引用方式有何不同：

<select ng-model='selection.selectedmethod' ng-init="selection.selectedmethod=companies[0]" ng-switch-when='N' style='float:left'>
  <option ng-repeat='companyoption in companies' value="{{companyoption}}">{{companyoption}}</option>
</select>

一种不同的(可能更好的)方法是使用“ControllerAs”语法,它具有为您执行此操作的效果.

angular.module('app',[])
    .controller('main',function($scope){

      this.Memethods = ['Same as Card/Account Name','VISA'];
      this.companies = ['Company Paid','MyAMEX'];
    })

<body ng-app="app" ng-controller="main as main">
  <div class='subcontent'>
    <input id="me" type="radio" class='choosemethod' ng-model="paymentmethod" value="Y">
    <label for="me" class='choosemethod'>Me</label>
    <input id="company" type="radio" ng-model="paymentmethod" value="N" class='choosemethod'>
    <label for="company" class='choosemethod'>My Company</label>
    <br/>
    <span class='helptext'>Who makes payments to this account?</span><span class='help' style='margin-left:20px;width:20px;height:20px;'>help</span>
  </div>

  <div class='paymentmethods subcontent' ng-switch on="paymentmethod">
    <select ng-model='main.selectedmethod' ng-init="main.selectedmethod=main.Memethods[0]" id='methods' ng-switch-when='Y'>
      <option ng-repeat="method in main.Memethods" value="{{method}}">{{method}}</option>
    </select>

    <select ng-model='main.selectedmethod' ng-init="main.selectedmethod=main.companies[0]" ng-switch-when='N' style='float:left'>
      <option ng-repeat='companyoption in main.companies' value="{{companyoption}}">{{companyoption}}</option>
    </select>

    <div class='clear'></div>
    <label for='methods'>Payment Method</label><span class='help' style='margin-left:20px;width:20px;height:20px;'>help</span>

  </div>
  <div>{{main.selectedmethod}}</div>
</body>

（编辑：李大同）

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