Html 如何在angular 5中使用带有ngfor的大型阵列
当我用ngfor页面显示100多个产品时,速度非常慢。 如果在ngFor中为100个项目调用一个方法,或者为一个项目在ngFor中设置很多元素,那么浏览器的性能会有问题吗 这是我的typescript代码,我通过http post请求从服务器获得一些产品Html 如何在angular 5中使用带有ngfor的大型阵列,html,angular,dom,browser,Html,Angular,Dom,Browser,当我用ngfor页面显示100多个产品时,速度非常慢。 如果在ngFor中为100个项目调用一个方法,或者为一个项目在ngFor中设置很多元素,那么浏览器的性能会有问题吗 这是我的typescript代码,我通过http post请求从服务器获得一些产品 public products:any = [] ; constructor( private setRouter: SetRouterService, private header :HeaderService, privat
public products:any = [] ;
constructor(
private setRouter: SetRouterService,
private header :HeaderService,
private cdr: ChangeDetectorRef,
private router : Router,
private crypto:EncryptDecryptService ,
private dataservices: DataService ,
private Httpservice :HttpService ,
private route: ActivatedRoute
) {
this.dataservices.update_loader(true);
this.dataservices.create_object_request( 'products', { 'type': 'default', 'number_click': 1 } );
this.my_products = this.Httpservice.Http_Post( this.dataservices.object_request ) // make request ......
.subscribe( // take success
data => {
if ( data['status'] == 'product' ) {
this.products = data['data']['products'];
this.build_pages_link( data['data']['pages_details']);
this.dataservices.update_loader(false);
}
},
error => console.log( error['data'] ) // take error .....
);
}
这是我用ngFor显示产品的html代码
<div class="width_products products-animation " *ngFor="let product of products ; let i = index" [ngClass]="{ 'width_products_open_menu':header.status_menu }" >
<div class="each_width_product" >
<div class="title_products more_detail_product" (click)="set_router({ path:product['company'].company_name+'/'+product.product_title , data:product.product_id , relative:true })">
{{product.product_title }}
</div>
<div class="dropdown_products">
<span class="glyphicon glyphicon-chevron-down"></span>
</div>
<div class="date_products">
<span class='glyphicon glyphicon-time'></span> {{product.product_date}}
</div>
<div class="image_profile_company " (click)="set_router({ path:product['company'].company_name , data: product['company'].company_id , relative:true })">
<img class="image_prof_admin" src="../../assets/images/products_image/{{product['company'].company_image}}">
</div>
<div class="image_product_primary " (click)="set_router({ path:product['company'].company_name+'/'+product.product_title , data:product.product_id , relative:true })">
<img class="image_product img_primary_product{{product.product_id}}" src="../../assets/images/products_image/{{product.product_image}}">
</div>
<div class="wish_list hover_all_wish notCloseDropdawnFavorite notCloseDropdawnCard" (mouseleave)="mouseLeave_wish( product )" (mouseenter) ="mouseHover_wish( product ,i )" id="wish_list{{product.product_id}}" (click)="header.add_wish_list( product )" [ngClass]="{'wish_list_hover': product_properties.index_product == i }">
</div>
<div class="about_wish" >
<div class="wish_list_write">
<div class="plus_icon">{{dataservices.language.add_wishlist}}</div>
</div>
<div class="wish_list_icon">
<button mat-mini-fab class="button_heart" >
<div *ngIf="header.wish_properties.wishList.length > 0; else emtyWish " >
<div *ngIf="check_wish( product ) ; else notinwish">
<mat-icon>favorite</mat-icon>
</div>
<ng-template #notinwish >
<mat-icon class="notCloseDropdawnFavorite notCloseDropdawnCard" [ngClass]="{'hide_border_heart' : product_properties.hover_wish_list && product_properties.index_product == i } ">favorite_border</mat-icon>
<mat-icon class="hearts_div_hover notCloseDropdawnFavorite notCloseDropdawnCard" [ngClass]="{'show_full_heart' : product_properties.hover_wish_list && product_properties.index_product == i } ">favorite</mat-icon>
</ng-template>
</div>
<ng-template #emtyWish>
<mat-icon [ngClass]="{'hide_border_heart' : product_properties.hover_wish_list && product_properties.index_product == i } ">favorite_border</mat-icon>
<mat-icon class="hearts_div_hover" [ngClass]="{'show_full_heart' : product_properties.hover_wish_list && product_properties.index_product == i } ">favorite</mat-icon>
</ng-template>
</button>
</div>
</div>
<div class="footer_products">
<span matTooltip="Views!">
<div class="button_footer_products">
<span class="glyphicon glyphicon-eye-open icon_eye"></span>
<div class="both_write ">
12889
</div>
</div>
</span>
<span matTooltip="Add to your card" class="notCloseDropdawnCard notCloseDropdawnFavorite " (click)="header.add_cart_list( product )">
<div class="button_footer_products">
<span class="glyphicon glyphicon-plus icon_eye notCloseDropdawnCard notCloseDropdawnFavorite" *ngIf="!check_cart( product ) ; else incart "></span>
<ng-template #incart>
<span class="glyphicon glyphicon glyphicon-ok icon_eye notCloseDropdawnCard notCloseDropdawnFavorite"></span>
</ng-template>
<div class="both_write ">
Cart
</div>
</div>
</span>
<span matTooltip="See Details!">
<div (click)="set_router({ path:product['company'].company_name+'/'+product.product_title , data:product.product_id , relative:true })" class="button_footer_products more_detail_product" id="<?php echo $result_all_products['id'] ?>">
<span class=" glyphicon glyphicon-option-horizontal icon_eye"></span>
<div class="both_write ">
More
</div>
</div>
</span>
</div>
<div class="prise_products">
Price:
<div class="both_prise_products prise_primary">
<del>$2500</del>
</div>
<div class="both_prise_products prise_secondary">
$3500
</div>
</div>
<div class="plus_height"></div>
</div>
</div>
{{product.product_title}
{{product.product_date}
{{dataservices.language.add_wishlist}
最喜欢的
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12889
运货马车
问题是每次在模板中执行某些操作(例如,移动鼠标)时,都会执行函数的代码。模板的生命周期导致了这一点,再加上您正在为阵列中的每个项创建该函数的实例。我建议你试试看
1-更改组件的更改检测策略
Component({
...,
changeDetection: ChangeDetectionStrategy.OnPush
})
MyComponent {}
2-减少从模板到组件中方法的调用次数(如果可以应用,请尝试使用管道)这是一个非常普遍的问题。你能提供你的代码吗?如果没有它,就很难知道问题在哪里。您好,请查看这篇文章,了解有关在StackOverflow上提问的内容:好的,谢谢您。我编辑了我的问题,但有人能帮我吗?我编辑了,但没有任何结果。@Kloderishaba您到底做了什么?check_wish()方法被多次调用,在里面放一个console.log,你们会看到我从服务器上获得了100个产品,并在浏览器中显示它们,每个产品都有两个选项“添加到愿望列表”和“添加到购物车列表”,如果单击“添加到愿望”或“购物车”将此项目添加到所选卡片或愿望中,并检查是否在愿望或购物车中添加,但现在我已经删除了所有这些控制器,而阿甘对one houndred产品的性能很慢。不要下载所有的产品。尝试使用分页或无限滚动,因为如果产品对象太重,可能会出现问题