在指令范围内。$表没有被AJAX请求后调用 [英] scope.$watch in a directive isn't being called after AJAX request

问题描述

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; 
}]);

下面是我如何调用它：

<my-filter model="someField" name="abcd" />

在该指令首次initalized，在 someField 是空的。以后，它是通过AJAX检索，且其值被填充在

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，我怎么能观看 someField 的值更新？当我做这从连接方式：

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 );
}

initalizing指令时，这只是调用一次，然后该值是空的。当该值通过AJAX检索（从 $ http.get ），这款手表的功能不再调用。然而，在我显示页面的其他部分 {{} someField} ，该值会更新时，Ajax请求被取出。因此，我不认为这个问题有做 $ scope.apply（）后Ajax请求。

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.

编辑： someField 被分配在控制器中。这里是code：

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);               
}
]);

该方法 ajax.getUser（）做了 $ http.get（）并返回其诺。在上面的code时，负荷方法被调用它设置的值 someField 。

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

$观看预计一个前pression这可以是一个函数或字符串。因此，它会工作，如果你将其更改为

$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() { ... });

查看此的jsfiddle 。

这篇关于在指令范围内。$表没有被AJAX请求后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！