[英]Dynamic Change *ngIf State with Function Angular
<ion-col sizeLg="4" size="12" *ngFor="let item of category.menu_items">
<ion-badge (click)="follow(item)" *ngIf="followcontrol(item.id)">Follow</ion-badge>
</ion-col>
When the page opening it's work correctly.当页面打开时它工作正常。 When click this button
followcontrol()
function result will change.当点击这个按钮时
followcontrol()
function 结果会改变。 My follow()
function:我的
follow()
function:
follow(item) {
this.request.postFollowed(item)
this.following(); // This is for succesfull message
}
followcontrol()
: followcontrol()
:
followcontrol(id){
return this.request.getFollowByID(this.followsdata, id) // this function control the data and return a boolean value.
}
How can i get the currently value of followcontrol()
after follow()
function worked?在
follow()
function 工作后,如何获取followcontrol()
的当前值?
Save the ids into an array (ids):将 id 保存到数组 (ids) 中:
ids: number[] = [];
follows: boolean[] = [];
ngOnInit() {
this.your_service.getCategory().subscribe(category => {
category.menu_items.forEach((item, index) => {
this.ids[index] = item.id;
this.followcontrol(item.id, index);
}
});
}
followcontrol(id, index) {
this.request.getFollowById(this.followsdata, id).subscribe(value => {
this.follows[index] = value;
});
}
in your template:在你的模板中:
<ion-col sizeLg="4" size="12" *ngFor="let item of category.menu_items; let i = index">
<ion-badge (click)="follow(item)" *ngIf="follows[i]">Follow</ion-badge>
</ion-col>
So, You'll avoid to use methods inside of your template (which emit side effects), and you have all data prepared from the initialization.因此,您将避免在模板内部使用方法(这会产生副作用),并且您已准备好初始化中的所有数据。
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