在父下拉列表更改时，我的第二个级联下拉列表不会在UI上更新

Question

我有两个级联下拉列表。当我选择第一个选项时，第二个下拉列表会相应更改。当我更改第一个选项时，第二个下拉列表中的选项似乎没有变化，但是当您在第二个下拉列表中单击过时选项时，UI上会显示更改，然后它们将成为正确的选项。

HTML:

<select id= 'primary' ng-model="offer.primary" ng-options="XXX.primary for XXX in categories"
                ng-change= setPrimary("offer.primary")>
            <option value="">Primary Business Category</option>
        </select>

        <select id= 'secondary' ng-model="offer.secondary" ng-disabled="!offer.primary"
                ng-options="XXX for XXX in SecondaryCategories" ng-change=setSecondary()>
            <option value="">Secondary Business Category</option>
        </select>

JS

    $scope.setPrimary = function () {
                $scope.secondaryCategories();
            };

            $scope.setSecondary = function () {
                }

    $scope.categories = [
                {primary: "Food and Drink"},
                {primary: "Healthcare"},
                {primary: "Recreation"},
                {primary: "Service"},
                {primary: "Shops"},
                {primary: "Travel"}
            ]

            $scope.secondaryCategories = function(){
                var Secondary = new Parse.Query(Categories);
                Secondary.limit(1000);
                Secondary.equalTo('primary', $scope.offer.primary['primary']);
                console.log('log3:' +" "+ $scope.offer.primary['primary']);
                Secondary.find({
                    success:function(list){
                        $scope.SecondaryCategories = _.filter(_.uniq(_.map(list, function(item){//this function is an iteratee and item is the key word!
                                return item.get('secondary')
                            }
                        ),true))
                        console.log($scope.SecondaryCategories);
                    },
                    error: function(error){alert("A mistake was made.");
                    }
                })
            }

我的数据源是一个简单的集合，其中primary位于列中，可能没有次要关系，或者可能有许多次要关系，而secondary位于其自己的列中，并且始终具有主要关系。