Javascript AngularJS：模型值更改时更新选择视图

我的

select

看起来像

   <select data-ng-model="transaction.category"
            class="form-control"
            data-ng-options="category.name group by category.parent for category in categories"
            required>
    </select>

angular.module('transactionService', ['ngResource']).factory('Transaction', function ($resource) {
    return $resource('/user/transactions/:transactionId',
        {transactionId: '@uuid'},
        {
            getRecent: {method: 'GET', params: {recent: true}, isArray: true},
            getForYearMonth: {method: 'GET', params: {}, isArray: true}
        });
});

我设置的值如下

var transaction = new Transaction();
transaction.name = $scope.transaction.name;
transaction.category = $scope.transaction.category.uuid;

类别

看起来像

[  { 
name: Alcohol & Bars
parent: Food & Drink
uri: /categories/9b1e97f2-ac7d-4caf-85fc-476cd97dd6cb
uuid: 9b1e97f2-ac7d-4caf-85fc-476cd97dd6cb
 } ,  { 
name: Coffee & Tea
parent: Food & Drink
uri: /categories/cf040e77-2faa-41de-b9f7-3749a42735ac
uuid: cf040e77-2faa-41de-b9f7-3749a42735ac
 } ...
]

当我从下拉列表中选择值时，一切正常

那么问题出在哪里？
在某些情况下，我希望根据一些预先填充的用户偏好设置

类别

那我该怎么办？
我做以下几点

$scope.templateSelected = undefined;
$scope.$watch('templateSelected', function () {
    if ($scope.templateSelected !== undefined) {
        $scope.transaction.category = $scope.templateSelected.category;
    }
}, true);

我希望

HTML

select元素上的值会被选中。但事实并非如此

问题？
如何根据

$scope.templateSelected.category

更新我的

选择选项

更新

事务

如下所示

   <select data-ng-model="transaction.category"
            class="form-control"
            data-ng-options="category.name group by category.parent for category in categories"
            required>
    </select>

angular.module('transactionService', ['ngResource']).factory('Transaction', function ($resource) {
    return $resource('/user/transactions/:transactionId',
        {transactionId: '@uuid'},
        {
            getRecent: {method: 'GET', params: {recent: true}, isArray: true},
            getForYearMonth: {method: 'GET', params: {}, isArray: true}
        });
});

---

默认情况下，角度跟踪基于对象参考的

中的选定值

设置

$scope.transaction.category=$scope.templateSelected.category时，
$scope.transaction.category
不是列表中的对象

您可以要求angular根据属性使用
按类别跟踪来识别所选值。uuid
：

data-ng-options="category.name group by category.parent for category in categories track by category.uuid"

请按我的需要添加该交易类别的代码。非常感谢你！