Question

我创建了一个JS对象，其方法调用$ http来检索值，但是当$ http完成后我想将此值赋给属性，我似乎无法能够得到这个值：

属性this.user总是以promise本身结束，但是我想分配从XHR请求返回的值或者在失败时未定义，我认为这是一个上下文问题，我只是不知道如何解决它

var Ticket = function(numint, company_id, user_id, title, description, priority, status, assignation, created_at) {
            this.numint         = numint;
            this.company_id     = company_id;
            this.user_id        = user_id;
            this.title          = title;
            this.description    = description;
            this.priority       = priority;
            this.status         = status;
            this.assignation    = assignation;
            this.created_at     = created_at;

            this.user           = undefined;

            this.getUser = function() {

                if(this.user_id === undefined)
                    return false;

                var http = 
                    $http({
                        method  : 'GET',
                        url     : '/users/' + this.user_id,
                        timeout : 100000,
                        headers : {'Content-Type': 'application/x-www-form-urlencoded'}
                    });

                this.user = http
                    .then(
                        function(data) {
                            return data;
                        }
                        , 
                        function() {
                            return undefined;
                        });

                return http;

            }
        };

Answer 1

var http是一个promise对象，因为Angular的$http服务的返回值是一个promise（docs）。一旦AJAX请求返回并且承诺已解决，请使用.then()获取返回值。

var self = this;

http.then(function (data) {
  self.user = data;
});

Answer 2

var Ticket = function(numint, company_id, user_id, title, description, priority, status, assignation, created_at) {
        var self = this; // new code
        self.numint         = numint; //use self inseat
        self.company_id     = company_id;

        this.getUser = function() {

            if(self.user_id === undefined) // you had one preblem here, because "this" here is direrent to the this.user_id you neded, so use self
                return false;

            var http = 
                $http({
                    method  : 'GET',
                    url     : '/users/' + this.user_id,
                    timeout : 100000,
                    headers : {'Content-Type': 'application/x-www-form-urlencoded'}
                }).then(function (data){
                      self.user = data
                   ;},
                 function () {
                  self.user= undefined;
                   });


        }
    };

Answer 3

将此值分配给不同的值或！或者我们.bind。

$http({
  method  : 'GET',
  url     : '/users/' + this.user_id,
  timeout : 100000,
  headers : {'Content-Type': 'application/x-www-form-urlencoded'}
}).then(function (data){
  this.user = data;
}.bind(this));

Angularjs $ http然后功能

3 个答案: