Javascript Angular UI日期插件：On Select不起作用

我正在与AngularJS的datepicker插件斗争。我有两个目标尚未实现：

单击日期后执行操作（请参阅app.directive 下）

不在指令声明内执行此操作，而是在特定控制器内执行此操作：

app.controller（'dateCtrl'，…）

下面是我的代码：

HTML:

<div ng-app="MyApp">

   <div ng-controller="someOtherCtrl"> ... </div>

   <div ng-controller="dateCtrl">

      <p>Pick date:</p>

      <input type="text" ng-model="date" ui-date="dateOptions" ui-date-format="yy-mm-dd" custom-datepicker/>

   </div>

   <div ng-controller="someOtherCtrl"> ... </div>

</div>

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

app.controller('dateCtrl', function($rootScope, $scope) {
        $scope.dateOptions = {
            dateFormat:'DD, d  MM yy',
            minDate: 0,
            maxDate: "+6M"
        };

        /* How can I access the on-select-method of my datepicker here inside this controller? */
});

app.directive("customDatepicker", function () {
    return {
        restrict: "A",
        require: "ngModel",
        link: function (scope, elem, attrs, ngModelCtrl) {
            elem.datepicker({
                onSelect: function (dateText) {
                    ngModelCtrl.$setViewValue(dateText);
                    scope.$apply();
                    /* This alert does not work: */
                    alert('i want this to be triggered, but it does not work');
                }
            });
        }
    }
});

单击日期时，不会触发警报。为什么？我需要如何调整代码

---

为了在app.controller声明中触发此选择操作，我需要做什么？

这是我为angularjs的日期选择器编写的代码，希望这对您有用。 HTML

---

这里是JSFIDLE

你能为它创建一个plunker或fiddle吗？

<div ng-app="myApp">
  <div ng-controller="dateCtrl">

    <label>Date : </label>
    <input ng-model="date" ui-date>
    <hr>
      <h1>  {{date | date: 'dd/MM/yyyy'}}</h1>
  </div>
</div>

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

myApp.directive('uiDate', function() {
    return {
      require: '?ngModel',
      link: function (scope, elem, attrs, ngModelCtrl) {
            elem.datepicker({
                onSelect: function (dateText) {
                    ngModelCtrl.$setViewValue(dateText);
                    scope.$apply();
                    /* This alert does not work: */
                    alert('i want this to be triggered, but it does not work');
                }
            });
        }
    };
  });

myApp.controller('dateCtrl', function($rootScope, $scope) {
        $scope.dateOptions = {
            dateFormat:'DD, d  MM yy',
            minDate: 0,
            maxDate: "+6M"
        };

        /* How can I access the on-select-method of my datepicker here inside this controller? */
});