[英]Angular child component does not detect change
我正在從父組件更新產品對象。 不知何故,子組件不會檢測到更改並且不會更新它。
產品.ts
export interface Product {
productId: number;
productName: string;
lastUpdated: string;
orders: Array<Order>
}
訂單.ts:
export interface Order {
orderId: number;
payments: Array<Payment>
}
付款.ts:
export interface Payment {
paymentId: number;
amount: Array<number>
}
父組件.html
<product-details [(product)]="product1" (refreshProduct)="refreshProduct()"></product-details>
父組件.ts
product1: Product = null;
refreshProduct() {
this.sub = this.productService.getTheLatestOrders().subscribe(
(data) => {
this.product1.lastUpdated = data.lastUpdated;
this.product1.orders.forEach(order => {
let latestOrderData = data.orders.find(d => d.orderId == order.orderId);
if(latestOrderData) {
order.payments = latestOrderData.payments;
}
});
// this.product1 = JSON.parse(JSON.stringify(this.product1)); --> It works if I add this
});
}
}
product-details.component.html(子組件)
<button id="refresh" name="refresh" (click)="refresh()" />
Last Updated : {{product.lastUpdated}}
<ng-container *ngFor="let order of product.orders">
<ng-container *ngFor="let payment of order.payments">
{{payment.date}} - {{payment.amount}}
</ng-container>
</ng-container>
product-details.component.ts(子組件)
@Input('product') product: Product;
@Output() refreshProduct = new EventEmitter<any>();
refresh() {
this.refreshProduct.emit();
}
我試圖明確聲明changeDetection: ChangeDetectionStrategy.Default
但沒有運氣。
如代碼中所述,如果我添加JSON.parse(JSON.stringify(this.product1));
那么它的工作原理。 所以似乎我需要創建一個新對象,以便更改檢測工作。 我想我可以使用擴展運算符 (object.assign) 來確保它創建一個新對象。 但是,我不確定如何使用傳播操作更新 refreshProduct() 方法中的產品。
我認為代碼將如下所示:
this.product1 = {...this.product1,
lastUpdated: data.lastUpdated,
orders: .... // --> Not sure how to loop through orders and update the payments
};
編輯:我想我設法做到了。
this.product1 = {...this.product1,
lastUpdated: data.lastUpdated,
orders: this.product1.orders.map((order) => {
let updatedOrder = data.orders.find(o => o.orderId == order.orderId);
return {...order, order.payments: updateOrder.payments};
})
};
請讓我知道是否有更好的解決方案。
嘗試這樣做:
refreshProduct() {
let temp: Product = {};
this.sub = this.productService.getTheLatestOrders().subscribe(
(data) => {
temp.lastUpdated = data.lastUpdated;
temp.orders.forEach(order => {
let latestOrderData = data.orders.find(d => d.orderId == order.orderId);
if(latestOrderData) {
order.payments = latestOrderData.payments;
}
});
this.product1 = temp;
});
}
}
這樣每次它都會將更新的值分配給產品。
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