我在每行中都有一个列表和一个复选框。我希望每当我单击一个复选框时，对象都需要根据复选框状态进行相应的更新，但是当我在复选框上点击时使用下面的内容，却遇到无法设置属性“ 已选中”的异常未定义或空引用
export class Custom{
name: string
empoloyeeID: number
checked:boolean
}
export class CheckboxListPage {
contacts:Array<Custom> = [];
constructor(public navCtrl: NavController, public navParams: NavParams) {
let customObj1 = new Custom();
customObj1.empoloyeeID = 1;
customObj1.name = "Ramakrishna";
let customObj2 = new Custom();
customObj2.empoloyeeID = 2;
customObj2.name = "Ramakrishna2";
this.contacts.push(customObj1);
this.contacts.push(customObj2);
}
updateCucumber(contact){
this.contacts[contact.id].checked = !contact.checked;
}
<ion-content padding>
<ion-list>
<ion-item *ngFor="let contact of contacts" (click)="update(contact)">
<!-- <ion-avatar item-start>
<img src="imgs/img_snow.jpg">
</ion-avatar> -->
<ion-avatar item-left>
<img src="https://ionicframework.com/dist/preview-app/www/assets/img/marty-avatar.png">
</ion-avatar>
<h2>{{contact.name}}</h2>
<p *ngIf="contact.id===1;else other_content">your if block</p>
<ng-template #other_content><p>your else block1</p></ng-template>
<ion-row>
<ion-col col-2 no-padding no-margin>
<ion-item no-padding no-margin no-lines>
<ion-checkbox [(ngModel)]="contact.checked" (ionChange)="updateCucumber(contact)"></ion-checkbox>
</ion-item>
</ion-col>
<ion-col col-10 no-padding no-margin>
<ion-item no-padding no-margin no-lines>
Agree to <a target="_blank" href="http://www.terms-of-service.com">Terms of Service</a>
and <a target="_blank" href="http://www.privacy-policy.com">Privacy Policy</a>.
</ion-item>
</ion-col>
</ion-row>
</ion-item>
</ion-list>
</ion-content>
答案 0 :(得分：0)
不确定我是否正确，但是如果您想在每次单击复选框时更新相应的联系人对象，则可以尝试如下操作：
<!DOCTYPE html>
<html ng-app="app">
<head>
<script data-require="angular.js@*" data-semver="4.0.0" src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.10/angular.min.js"></script>
<script data-require="angular.js@*" data-semver="4.0.0" src="script.ts"></script>
<script data-require="angular.js@*" data-semver="4.0.0" src="system.config.js"></script>
<script data-require="angular.js@*" data-semver="4.0.0" src="tsconfig.json"></script>
<link rel="stylesheet" href="style.css" />
<script src="script.js"></script>
</head>
<body ng-controller="myctrl">
<div id="wrapper" class="wrapper">
<div id="aside" class="sidebar">
<div>
<ul class="nav">
<li><a href="#">Home</a></li>
<li><a href="#">Experience is the key of the item of the rest of the kind</a></li>
<li><a href="#">Services</a></li>
<li><a href="#">Bio</a></li>
<li><a href="#">Contact</a></li>
</ul>
</div>
</div>
<!-- /Aside -->
<div class="hideButton">
<div class="Aligner">
<a class="button" ng-click="toggle()"></a>
</div>
</div>
<div id="content" class="content">
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<h2>Easy to use</h2>
<div>
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</div>
</div>
<!-- /Content -->
</div>
</body>
</html>您的HTML几乎保持不变：
export class CheckboxListPage {
contacts = [
{
name: "Ramakrishna",
id: 1,
selected: false
},
{
name: "Ramakrishna2",
id: 2,
selected: false
}
]
constructor(public navCtrl: NavController,
public navParams: NavParams) {}
updateCucumber(contact) {
contact.selected = !contact.selected;
}
}