重复选择ng-option绑定问题

Question

我的ng-options有问题。 我有一个模态，其中重复选择fill。从其父视图获取数据的模式。在第一次打开（模态）之后，它运行良好，但在我再次打开它之后，它不会绑定ng-options字段中的最后一个选定值。

modal.html

select

modalController.js

<div class="modal-body">
    <div data-ng-repeat="filter in filters track by $index">
        <div class="form-group">
            <label>{{filter.column_label}}</label>
            <select class="form-control" ng-model="selectedFilter"
                    ng-options="obj.value for obj in filter.column_enums track by obj.key "
                    ng-change="change($index)">
                <option value="">Please choose</option>
            </select>
        </div>
    </div>
</div>
<div class="modal-footer">
    <button class="btn btn-success" type="button" ng-click="setFilter()">save</button>
    <button class="btn btn-warning" type="button" ng-click="cancel()">cancel</button>
</div>

parentController

app.controller('filterController', function($scope, scope, $uibModalInstance){

    $scope.selectedFilter = scope.parentData.selectedValues; //first time it is empty
    $scope.filters = scope.parentData.filters;

    $scope.change = function (index){

        $scope.selectedFilter[index] = this.selectedFilter;
    };

    $scope.setFilter = function (){
        scope.parentData.selectedValues = $scope.selectedFilter;

        $uibModalInstance.dismiss();
    }
}