[英]Why doesn't my Reactive Form in Angular 4 update the value when set by datetimepicker
[英]Why I can't update the value of an Angular reactive form field with a calculated value?
我正在使用反應形式開發 Angular 應用程序。 在組件的 HTML 代碼中,我有這個字段必須包含一個在執行操作時計算的值(在我的前端更改另一個值)。
<div class="row">
<div class="col-2">
<p>Valore attuale asset</p>
</div>
<div class="col-10">
<p-inputNumber id="deductible" formControlName="current_asset_value"
mode="currency" currency="EUR" locale="de-DE"
[disabled]="true">
</p-inputNumber>
</div>
</div>
如您所見,它顯示了current_asset_value formControlName 的值。
然后進入這個組件的 TypeScript 代碼,我在我的ngOnInit()方法中定義了表單:
this.assetDetailsForm = this.fb.group({
asset_type: [this.assetDetailsSelected.asset_type, [Validators.required]],
asset_model: [this.assetDetailsSelected.asset_model, [Validators.required]],
guarantee_start_date: [this.assetDetailsSelected.guarantee_start_date, []],
guarantee_duration: [2, []],
guarantee_end_date: [null, []],
asset_action: [this.assetDetailsSelected.asset_action, []],
allocation: [null, []],
asset_features: [this.assetDetailsSelected.asset_features, [Validators.required]],
serial_number: [this.assetDetailsSelected.serial_number, [Validators.required]],
accessories: [this.assetDetailsSelected.accessories, [Validators.required]],
allocation_date: [this.assetDetailsSelected.allocation_date, [Validators.required]],
company: [this.assetDetailsSelected.company, [Validators.required]],
notes: [this.assetDetailsSelected.notes, [Validators.required]],
invoice: [this.assetDetailsSelected.invoice, [Validators.required]],
invoice_cost: [this.assetDetailsSelected.invoice_cost, [Validators.required]],
deductible: [this.assetDetailsSelected.deductible, [Validators.required]],
current_asset_value: [null, []],
status: [this.assetDetailsSelected.status, []]
});
如您所見,該字段值實際上是 null 並且可以:
current_asset_value: [null, []],
然后,當用戶在此表單上執行操作時(當invoice_cost或deductible字段的值發生變化時),執行設置current_asset_value表單字段值的組件方法。 我是這樣做的:
public calculateAssetDepractionValue() {
let today:Date = new Date();
console.log("TODAY DATE: ", today);
console.log("GUARANTEE START DATE: ", this.assetDetailsSelected.guarantee_start_date);
let monthsFromPurchase:number = this.monthDiff(today, this.assetDetailsSelected.guarantee_start_date);
console.log("monthsFromPurchase: " + monthsFromPurchase);
let monthlyDevaluation = (this.assetDetailsSelected.invoice_cost - this.deductibleNg) / 36;
let actualValue = this.assetDetailsSelected.invoice_cost - (monthlyDevaluation * monthsFromPurchase);
console.log("actualValue: " + actualValue);
this.assetDetailsForm.value.current_asset_value = actualValue;
}
此方法已正確執行(我可以使用 dubugger 和 console.log() 輸出看到它)但設置值未在我的表單中更新。 這就是我得到的:
正如您所看到的,當我更改 highligted 表單字段的值時,執行了calculateAssetDepractionValue()方法並計算了actualValue ,最后它執行了這一行來設置/更新current_asset_value表單字段的值:
this.assetDetailsForm.value.current_asset_value = actualValue;
但正如您在打印屏幕中看到的那樣, current_asset_value的值並未呈現到我的視圖中。
為什么? 怎么了? 我錯過了什么? 我該如何嘗試解決此問題?
嘗試使用以下任何 function 方法。
this.assetDetailsForm.get('current_asset_value').setValue(actualValue);
this.assetDetailsForm.controls.current_asset_value.setValue(actualValue);
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