Question

我想要实现的是一个产生lisof Metacategories的下拉列表。一旦用户选择元类别，该参数应该传递到$ scope.meta（）中的函数的URI。然后（...）。但是，我传递的参数是类别; NG-模型=＆＃34;类别＆＃34 ;.此参数未发送到URI，我收到错误：

TypeError：无法读取属性＆＃39;类别＆＃39;未定义的

HTML：

 </select></center >
<center> <select ng-model="category"  > <!-- This produces drop down list from which the users selects a category which should then get passed to the meta1() function as a parameter to produce a further list for the drop down after that-->
<option size=50 value="" selected>Select a meta category</option>
 <option ng-repeat="meta in metas.metas" value="{{meta}}">{{meta}} </option>

</select></center>
<center> <select ng-model="category"  >
<option size=50 value="" disabled selected>Select a category</option>
 <option ng-repeat="category in categories.categories" value="{{category}}">{{category}} </option>

 </select></center>

角：

myApp.config(['$routeProvider', function($routeProvider) {
$routeProvider.when('/post', {
    templateUrl: 'templates/post.html',
    controller: 'PostCtrl'
})
}])
.controller('UserListCtrl', function ($scope, $http) {
$scope.list = function () { // this gets the list of places which works completely fine.
    $http.get('http://94.125.132.253:8001/getuncategorisedplaces').success(function (data) {

        $scope.places = data;
        console.log(data);
        $scope.message = 'List of Uncategorised places';
        $scope.meta = function () { // this gets list of meta categories, which is working fine.
            return $http.get('http://94.125.132.253:8000/getmetas').success(function (data) {

                $scope.metas = data;
                console.log(data);
                $scope.message = 'List of Uncategorised places';
            })
        }

//下面的函数应该从HTML中选择的上一个函数中获取参数类别。一旦发生这种情况，参数类别应该作为formdata.category（下面）传递，它将获得类别列表。

        $scope.meta().then(function (data) {
            var formdata = {
                'category': this.category,
            }
            var inserturl = 'http://94.125.132.253:8000/getcategories?meta=' + formdata.category;
            $http.get(inserturl).success(function (data) {

                $scope.categories = data;
                console.log(formdata.category);
                console.log(data);
                $scope.message = 'List of Uncategorised places';
            });


        });
    })
}
$scope.list();

Answer 1

我认为错误是由此引起的：

$scope.meta().then(function meta1($scope,$http) {

因为meta方法没有返回一个promise。如果你这样做，meta方法可以返回一个承诺：

$scope.meta= function(){
  return $http.get('http://94.125.132.253:8000/getmetas').success(function (data) {
    $scope.metas = data;
    console.log(data);
    $scope.message = 'List of Uncategorised places';
    return data;
  });
};

你可以将对meta的调用更改为

$scope.meta().then(function(data) {
...
}

Answer 2

缺少return。

$scope.meta应return承诺让您能够使用.then()

$scope.meta= function(){
    return $http.get('http://94.125.132.253:8000/getmetas').success(function(...
        ...
}

$scope.meta().then(function (data) {
    // do something with data
});

.then angularjs中的函数无法识别参数

2 个答案: