问题描述
限时送ChatGPT账号..我有以下指令:
MyApp.directive('myFilter', ['$filter','$rootScope',
function($filter, $rootScope)
{
var dir = {};
dir.restrict = 'E';
dir.templateUrl = 'views/myFilter.html';
dir.replace = true;
dir.scope =
{
name: '@',
model: '=',
};
dir.link = function(scope,el,attrs)
{
//stuff here
}
return dir;
}]);
这是我调用它的方式:
<my-filter model="someField" name="abcd" />
当指令第一次初始化时,someField
是空的.稍后通过ajax检索,并填入其值.
When the directive is first initalized, the someField
is empty. Later on, it is retrieved via ajax, and its value is filled in.
问题是,我怎样才能看到 someField
的值被更新?当我通过链接方法执行此操作时:
Question is, how can I watch for the value of someField
to be updated? When I do this from the link method:
scope.$watch(scope.model, function()
{
console.log( "changed, new val: ", scope.model );
}
这只会在初始化指令时调用一次,然后值为空.当通过ajax(来自$http.get
)检索值时,不会再次调用此监视函数.但是,在我显示 {{someField}}
的页面的其他部分,该值会在获取 ajax 请求时更新.所以我认为问题与在 ajax 请求之后执行 $scope.apply()
无关.
This is only called once, when initalizing the directive, and the value then is empty. When the value is retrieved via ajax (from $http.get
), this watch function is not called again. However, in other parts of the page where I'm displaying {{someField}}
, that value DOES update when ajax request is fetched. So I don't think the problem has to do with doing $scope.apply()
after ajax request.
someField
在控制器中分配.代码如下:
someField
is assigned in the controller. Here is the code:
MyApp.controller('myCtrl',
['$scope', '$rootScope', '$routeParams',
'ajax', '$filter',
function($scope, $rootScope, $routeParams, ajax, $filter)
{
var userId = parseInt( $routeParams.userId );
$scope.loaded = false;
$scope.someField = ""; //initalize with empty value
var load = function(data)
{
$scope.loaded = true;
$scope.someField = data.someField;
};
ajax.getUser(userId).success(load);
}
]);
方法ajax.getUser()
执行一个$http.get()
并返回它的promise
.在上面的代码中,调用了 load
方法来设置 someField
的值.
The method ajax.getUser()
does a $http.get()
and returns its promise
. In the code above, the load
method is called which sets the value of someField
.
推荐答案
$watch
需要一个可以是函数或字符串的表达式.因此,如果您将其更改为
$watch
expects an expression that can be either a function or a string. So, it'll work if you change it to
scope.$watch('model', function() { ... });
或
scope.$watch(function() { return scope.model; }, function() { ... });
查看这个jsFiddle.
这篇关于指令中的 scope.$watch 在 AJAX 请求后没有被调用的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
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