javascript - 使用 angularjs 将复选框设置为选中时导致错误

Question

这是 html:

<span ng-repeat="category in categories">
      <label class="checkbox-inline" for="{{category.id}}">
        <input type="checkbox" ng-checked="check(category.id)" ng-click="saveRoleMenu($event,category.id)" name="group" id="{{category.id}}" />
        {{category.name}}
      </label>
</span>

这是我的 Controller :

//get all the menus
authorityService.getMenus().then(function(response) {
    $scope.categories = response.data.data; //get all the menus success
})

//get the user's menus
var roleId = sessionStorage.getItem("roleId");
authorityService.getMenusByRoleId(roleId).then(function(response) {
    $scope.userMenu = response.data.data; //get the user's menu success
})
$scope.saveRoleMenu = function($event, id) {
    var checkbox = $event.target;
    if (checkbox.checked) {
        var roleId = $location.search().id;
        authorityService.saveRoleMenu(roleId, id).then(function(response) {
            if (response.data.code == 0) {
                alert("success！");
            }
        })
    }
}

$scope.check = function(value) {
    //error caused here
    for (var i = 0; i < $scope.userMenu.length; i++) {
        if(value == $scope.userMenu[i].id){
            return true;
        }else{
            return false;
        }
    }
}

我想将$scope.userMenu中的值设置为选中复选框，但在检查函数中，导致错误“无法读取未定义的属性'长度'”，这是什么原因错误？

Answer 1

Cannot read property 'length' of undefined

表示$scope.userMenu未定义。 先定义 $scope.userMenu，然后再为其赋值。

$scope.userMenu = [];
var roleId = sessionStorage.getItem("roleId");