Angular $ watch问题 [英] Angular $watch problem
本文介绍了Angular $ watch问题的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在学习Angular。请告诉我为什么最底部的$ watch不起作用：
I am learning Angular. Please tell me why the $watch at the very bottom does not work:
<html>
<head>
<link rel="Stylesheet" href="c.css" type="text/css" />
</head>
<body ng-app ng-controller='StudentListController'>
<ul >
<li ng-repeat='student in students'>
<a href='/student/view/{{student.id}}' class="menu-{{student.valid}}">{{student.name}}</a>
<input type="text" ng-model="student.quantity" />
</li>
</ul>
<button ng-click="Sum()" class="menu-true">Sum</button>
<div>{{sum}}</div>
</body>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.0.1/angular.min.js"></script>
<script>
var students = [{ name: 'Mary Contrary', id: '1', valid: 'true', quantity: 0 },
{ name: 'Jack Sprat', id: '2', valid: 'false', quantity: 0 },
{ name: 'Jill Hill', id: '3', valid: 'false', quantity: 0 }];
function StudentListController($scope)
{
$scope.students = students;
$scope.sum = 0;
$scope.Sum = function ()
{
$scope.sum = 0;
for (var i = 0; i < $scope.students.length; i++)
{
$scope.sum = parseFloat($scope.sum) + parseFloat($scope.students[i].quantity);
}
};
$scope.$watch($scope.students[1], $scope.Sum, 'true');
}
</script>
</html>
推荐答案
最底层的手表不起作用：
watch at the very bottom does not work:
<html>
<head>
<link rel="Stylesheet" href="c.css" type="text/css" />
</head>
<body ng-app ng-controller='StudentListController'>
<ul >
<li ng-repeat='student in students'>
<a href='/student/view/{{student.id}}' class="menu-{{student.valid}}">{{student.name}}</a>
<input type="text" ng-model="student.quantity" />
</li>
</ul>
<button ng-click="Sum()" class="menu-true">Sum</button>
<div>{{sum}}</div>
</body>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.0.1/angular.min.js"></script>
<script>
var students = [{ name: 'Mary Contrary', id: '1', valid: 'true', quantity: 0 },
{ name: 'Jack Sprat', id: '2', valid: 'false', quantity: 0 },
{ name: 'Jill Hill', id: '3', valid: 'false', quantity: 0 }];
function StudentListController(
scope）
{
scope) {
scope.students = students;
scope.students = students;
这篇关于Angular $ watch问题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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