The drop-down menu is not visible

Question

The drop-down menu is not visible

Query -

Having an issue with two dropdowns in my view. The second dropdown is dependent on the first one, but for some reason, the second dropdown is not updating as expected.

// First dropdown

  <select ng-controller="myController"
             ng-options="customer.name for customer in customerDetailData"  ng-model="customer"
             ng-change="updateCost(customer)">
                <option value="">Please select customer</option>
    </select>

// Second dropdown

<select ng-controller="myController"
         ng-options="cc.name for cc in customerCostData">
      <option value="">Please select cost</option>
</select>

// Controller

(function() {
    var myController = function($scope,Service){
        $scope.customerDetailData;
        Service.cust()
            .success(function(data){
                console.log(data)
                $scope.customerDetailData = data;
            })
            .error(function(status,error){
            })

        $scope.customerCostData;
        $scope.updateCost=function(customer){
            Service.cost(customer.id)
                .success(function(cost){
                    $scope.customerCostData= cost
                })
                .error(function(status,data){
                    console.log(status);
                    console.log(data);
                })
        }
    };
    myController .$inject = ['$scope','Service'];
    angular.module('app').controller('myController ',myController );
}());

Am I overlooking something? The data is being retrieved successfully in the console. Any guidance would be appreciated.

javascript angularjs

Answer 1

Answer №1

Here are a couple of important steps to follow:

The primary issue is that the ng-controller is being attached to each select individually. This results in the creation of two separate controllers, one for each select, causing them to have different scopes. To resolve this, you should attach the ng-controller attribute to a parent element, such as the form.
The second issue is that Angular does not automatically update an element simply because the scope variable is used in ng-options. To address this, you need to assign a ng-model so that Angular can properly watch it.

Below is an example of the code with two distinct controller instances. Notice the presence of 2 alerts:

<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/angularjs/1.3.4/angular.min.js"></script>
    <form ng-app="myApp">
         <select ng-controller="myController"
             ng-options="customer.name for customer in customerDetailData" ng-model="customer"
             ng-change="updateCost(customer)">
            <option value="">Please select customer</option>
        </select>

        <select ng-controller="myController"
            ng-options="cc.name for cc in customerCostData" ng-model="customercustomerCostData">
            <option value="">Please select cost</option>
        </select>
    </form>

    <script type="text/javascript">
        (function () {
            var myApp = angular.module('myApp', []);

            var myController = function ($scope) {
                alert('myController created');
                $scope.customerDetailData = [{ id: 1, name: "bob" }, { id: 2, name: "fred" }];

                
                $scope.updateCost = function (customer) {
                    $scope.customerCostData = [{ name: customer.id.toString() }, { name: 'x' }];
                }
            };
            myController.$inject = ['$scope'];
            myApp.controller('myController', myController);
        }());
    </script>

Now, let's consider the scenario with a single ng-controller applied to the form and ng-model="customerCostData" on the second select, allowing it to function correctly:

<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/angularjs/1.3.4/angular.min.js"></script>
    <form ng-app="myApp" ng-controller="myController">
         <select
             ng-options="customer.name for customer in customerDetailData" ng-model="customer"
             ng-change="updateCost(customer)">
            <option value="">Please select customer</option>
        </select>

        <select
            ng-options="cc.name for cc in customerCostData" ng-model="customercustomerCostData">
            <option value="">Please select cost</option>
        </select>
    </form>

    <script type="text/javascript">
        (function () {
            var myApp = angular.module('myApp', []);

            var myController = function ($scope) {
                alert('myController created');
                $scope.customerDetailData = [{ id: 1, name: "bob" }, { id: 2, name: "fred" }];

                
                $scope.updateCost = function (customer) {
                    // Simulating an AJAX call
                    $scope.customerCostData = [{ name: customer.id.toString() }, { name: 'x' }];
                }
            };
            myController.$inject = ['$scope'];
            myApp.controller('myController', myController);
        }());
    </script>

Answer 2

Here are a couple of important steps to follow:

The primary issue is that the ng-controller is being attached to each select individually. This results in the creation of two separate controllers, one for each select, causing them to have different scopes. To resolve this, you should attach the ng-controller attribute to a parent element, such as the form.
The second issue is that Angular does not automatically update an element simply because the scope variable is used in ng-options. To address this, you need to assign a ng-model so that Angular can properly watch it.

Below is an example of the code with two distinct controller instances. Notice the presence of 2 alerts:

<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/angularjs/1.3.4/angular.min.js"></script>
    <form ng-app="myApp">
         <select ng-controller="myController"
             ng-options="customer.name for customer in customerDetailData" ng-model="customer"
             ng-change="updateCost(customer)">
            <option value="">Please select customer</option>
        </select>

        <select ng-controller="myController"
            ng-options="cc.name for cc in customerCostData" ng-model="customercustomerCostData">
            <option value="">Please select cost</option>
        </select>
    </form>

    <script type="text/javascript">
        (function () {
            var myApp = angular.module('myApp', []);

            var myController = function ($scope) {
                alert('myController created');
                $scope.customerDetailData = [{ id: 1, name: "bob" }, { id: 2, name: "fred" }];

                
                $scope.updateCost = function (customer) {
                    $scope.customerCostData = [{ name: customer.id.toString() }, { name: 'x' }];
                }
            };
            myController.$inject = ['$scope'];
            myApp.controller('myController', myController);
        }());
    </script>

Now, let's consider the scenario with a single ng-controller applied to the form and ng-model="customerCostData" on the second select, allowing it to function correctly:

<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/angularjs/1.3.4/angular.min.js"></script>
    <form ng-app="myApp" ng-controller="myController">
         <select
             ng-options="customer.name for customer in customerDetailData" ng-model="customer"
             ng-change="updateCost(customer)">
            <option value="">Please select customer</option>
        </select>

        <select
            ng-options="cc.name for cc in customerCostData" ng-model="customercustomerCostData">
            <option value="">Please select cost</option>
        </select>
    </form>

    <script type="text/javascript">
        (function () {
            var myApp = angular.module('myApp', []);

            var myController = function ($scope) {
                alert('myController created');
                $scope.customerDetailData = [{ id: 1, name: "bob" }, { id: 2, name: "fred" }];

                
                $scope.updateCost = function (customer) {
                    // Simulating an AJAX call
                    $scope.customerCostData = [{ name: customer.id.toString() }, { name: 'x' }];
                }
            };
            myController.$inject = ['$scope'];
            myApp.controller('myController', myController);
        }());
    </script>

Answer 3

Answer №2

Has the cost data been fetched using an Ajax request? If so, you may need to trigger a $digest cycle to update the UI with the new model changes. One way to do this is by wrapping the cost assignment in a $timeout or $apply function.

$timeout(function () {
    $scope.customerCostData = cost;
});

Alternatively,

$scope.$apply(function () {
    $scope.customerCostData = cost;
});

Answer 4

Has the cost data been fetched using an Ajax request? If so, you may need to trigger a $digest cycle to update the UI with the new model changes. One way to do this is by wrapping the cost assignment in a $timeout or $apply function.

$timeout(function () {
    $scope.customerCostData = cost;
});

Alternatively,

$scope.$apply(function () {
    $scope.customerCostData = cost;
});

The drop-down menu is not visible

Answer №1

Answer №2

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