绑定选中的项目angularjs

Question

我不能在控制器中使用selectedItem1进行以下代码中的一些计算:

  <div class="col-md-3">
          <label>Vendere:</label> 
          <select ng-model="selectedItem1" ng-options="(rosa.nome+' '+rosa.costo) for rosa in rose"></select>
   </div>

与以下控制器:

var app = angular.module('App', []); 
app.controller('Ctrl', function($scope, $http){

$scope.budget0=60;
    $scope.budget1=$scope.budget0 - $scope.selectedItem1.someprop;
}

我能理解为什么?我哪里错了?

Answer 1

我猜你需要给selectedItem1初始值看看下面的例子会帮助你:——

var app = angular.module('App', []);
app.controller('Ctrl', function($scope, $http) {  
  $scope.rose = [{
    'nome': "abc",
    'costo':110
  }, {
    nome: "xyz",
    costo: 10
  }];
  $scope.selectedItem1 =  $scope.rose[0];// default selected item
  
  $scope.budget0 = 60;
  $scope.budget1 = $scope.budget0 - $scope.selectedItem1.costo;
  
  $scope.change = function(){
    $scope.budget1 = $scope.budget0 - $scope.selectedItem1.costo;
    console.log($scope.selectedItem1);  
    console.log($scope.budget0 +"-"+ $scope.selectedItem1.costo +"="+$scope.budget1);  
  }
  
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="App" ng-controller="Ctrl">
  <select ng-model="selectedItem1" ng-change="change()"
          ng-options="(rosa.nome+' '+rosa.costo) for rosa in rose"></select>
  <br/>
  {{"budget1 == "+budget1}}
</div>