AngularJS输入监视$ valid或$ error [英] AngularJS input watch $valid or $error

问题描述

我正在尝试$watch控件的$error或$valid值.这是控件:

I'm trying to $watch the $error or the $valid value of a control. This is the control:

<form id="myForm" name="myForm"> 
  <input name="myInput" ng-model="myInputMdl" business-validation/>
</form>

business-validation是一个自定义指令，可更改控件的有效性.我已经根据在

business-validation is a custom directive that alters the validity of the control. I've attempted the following approaches (using either $valid or $error) based on what I've read at AngularJS directive watch validity:

1. 这不起作用，因为$valid在myForm.myInput上不存在.

$scope.$watch('myForm.myInput.$valid', function (isValid) {
  $scope.usefulVariable = step3.CreditCardNumber.$valid;
},true);

此功能不起作用，因为显然无法观看validity.valid.

$scope.$watch('myForm.myInput.validity.valid', function (isValid) {
  $scope.usefulVariable = step3.CreditCardNumber.$valid;
},true);

这不起作用，因为每次更改都不会监视$scope.myInputMdl.

$scope.$watch('$scope.myInputMdl', function (isValid) {
  $scope.usefulVariable = step3.CreditCardNumber.$valid;
},true);

不能从控制器监视有效性吗?

Can't the validity be watched from a controller?

编辑

我不是要编写或编辑business-validation指令.我正在尝试的是从窗体的控制器$watch $valid或$error.

I'm not trying to write or edit business-validation directive. What I'm trying is to $watch $valid or $error from form's controller.

编辑2

控制器的代码是:

app.controller('WizardBusinessActionCtrl',
   function ($scope, $http, $parse, $filter, wizardBusinessActionService, $timeout) {
     //controller code
   }
);

推荐答案

我看不出您的第一个变体不起作用的任何原因.

I don't see any reason why your first variant shouldn't work.

HTML:

<div ng-app="myApp">
    <div data-ng-controller="MainController">
        <form name="myForm"> 
            <input name="myInput" ng-model="myInputMdl" business-validation />
        </form>
    </div>
</div>

控制器和指令:

var myApp = angular.module('myApp', []);

myApp.controller('MainController', function ($scope) {
    $scope.$watch('myForm.myInput.$valid', function (validity) {
        console.log('valid', validity);
    });
});

myApp.directive('businessValidation', function () {
    return {
        restrict: 'A',
        require: 'ngModel',
        link: function (scope, elem, attr, ctrl) {
            function validate (input) {
                return input === 'hello';
            }

            ctrl.$parsers.unshift(function (value) {
                var valid = validate(value);
                ctrl.$setValidity('businessValidation', valid);
                return valid ? value : undefined;
            });

            ctrl.$formatters.unshift(function (value) {
                ctrl.$setValidity('businessValidation', validate(value));
                return value;
            });
        }
    };
});

$valid属性值将在myInput有效性更改时更改，并且将触发$watch回调.

$valid property value will change when myInput validity changes, and $watch callback will be fired.

请参阅示例: http://jsfiddle.net/Lzgts/287/

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