我的一个项目组件有问题。应用启动时,我会调用使用“ getAboutMeById”功能获取用户详细信息,并在“ site-header.component.ts”上,在控制台中出现以下错误,但是在页面加载完成后可以看到图像。
我尝试将数据按原样放入服务中,但是得到了相同的结果
组件:
export class SiteHeaderComponent implements OnInit {
aboutMe: AboutMe = null;
year: number = new Date().getFullYear();
@Output() navigationClickFired = new EventEmitter<string>();
constructor(private moranmonoService: MoranMonoService) { }
ngOnInit() {
this.getAboutMeById(1);
}
getAboutMeById(id: number) {
this.moranmonoService.GetAboutMeById(id).subscribe(res => {
let result = <AboutMe>res;
if (result != null) {
this.aboutMe = new AboutMe(result.name, result.emailAddress, result.phoneNumber, result.homeAddress, result.profilePhotoUrl,
result.profession, result.introduction, result.cvFileUrl, result.experience);
} else {
console.log('AboutMeComponent | getAboutMeById: Encountered an error.', result);
}
});
}
onNavigationClick(linkName: string) {
this.navigationClickFired.emit(linkName);
}
}
HTML代码:
<header id="site_header" class="header mobile-menu-hide">
<div class="header-content clearfix">
<div class="my-photo">
<img src="{{aboutMe.profilePhotoUrl}}" alt="image" class="img-responsive" style="max-width: 100px">
</div>
<div class="site-title-block">
<div class="site-title">{{ aboutMe.name }}</div>
</div>
<div class="site-nav">
<ul id="nav" class="site-main-menu">
<li>
<a class="pt-trigger" (click)="onNavigationClick('AboutMe')" href="#about-me">About Me</a>
</li>
<li>
<a class="pt-trigger" (click)="onNavigationClick('Resume')" href="#resume">Resume</a>
</li>
<!-- <li>
<a class="pt-trigger" href="#portfolio">Portfolio</a>
</li>
<li>
<a class="pt-trigger" href="#blog">Blog</a>
</li> -->
<li>
<a class="pt-trigger" (click)="onNavigationClick('Contact')" href="#contact">Contact</a>
</li>
</ul>
</div>
<div class="copyrights">All rights {{ year }}</div>
</div>
</header>
<div class="mobile-header mobile-visible">
<div class="mobile-logo-container">
<div class="mobile-header-image">
<a href="#">
<img src="{{aboutMe.profilePhotoUrl}}" alt="image">
</a>
</div>
<div class="mobile-site-title"><a href="#">{{aboutMe.name}}</a></div>
</div>
<a class="menu-toggle mobile-visible">
<i class="fa fa-bars"></i>
</a>
</div>
<div class="lmpixels-arrows-nav">
<div class="lmpixels-arrow-left"><i class="lnr lnr-chevron-left"></i></div>
<div class="lmpixels-arrow-right"><i class="lnr lnr-chevron-right"></i></div>
</div>
服务:
@Injectable({
providedIn: 'root'
})
export class MoranMonoService {
baseurl = environment.baseURL;
constructor(private httpClient: HttpClient) { }
GetAboutMeById(id: number) {
let reqHeader = new HttpHeaders();
reqHeader.append('Content-Type', 'application/json');
return this.httpClient.get(this.baseurl + 'api/AboutMe/get-aboutme-byId?id=' + id, { headers: reqHeader });
}
GetResumeEntities() {
return this.httpClient.get(this.baseurl + 'api/Resume/get-resume-entites');
}
GetExperienceEntities() {
return this.httpClient.get(this.baseurl + 'api/Experience/get-expirence-entites');
}
SendEmail(contact: Contact) {
return this.httpClient.post(this.baseurl + 'api/contact/send-email', contact);
}
}
我希望图像加载时没有错误,但出现以下错误:
ERROR TypeError: Cannot read property 'profilePhotoUrl' of null
at Object.eval [as updateRenderer] (SiteHeaderComponent.html:29)
at Object.debugUpdateRenderer [as updateRenderer] (core.js:11080)
at checkAndUpdateView (core.js:10456)
at callViewAction (core.js:10692)
at execComponentViewsAction (core.js:10634)
at checkAndUpdateView (core.js:10457)
at callViewAction (core.js:10692)
at execComponentViewsAction (core.js:10634)
at checkAndUpdateView (core.js:10457)
at callWithDebugContext (core.js:11344)
我的猜测是您的SiteHeader组件的html文件正在尝试访问aboutMe变量,而您的服务还没有加载数据。等待数据上传,您的aboutMe变量仍处于初始状态,为null。
如果错误与'profilePhotoUrl'属性有关,是因为它必须是html文件中第一个必需的属性。
解决方案是将基于aboutMe变量的所有html元素包装在带有* ngIf内部的元素中>
<div *ngIf="aboutMe">
<img src="aboutMe.profilePhotoUrl" />
<div>