如何计算项目总价和总价角反应表单数组

Question

我要数 ItemTotal = 数量 * UnitPrice 和发票总价。请建议我编写正确的方法来计算总计和项目总计。

medicinePurchaseForm: FormGroup;

ngOnInit(): void {
    this.initForm();
}

  private initForm() {
    this.medicinePurchaseForm = new FormGroup({
      prescriptionId: new FormControl(),
      subtotal: new FormControl(),
      purchaseMedicineList: new FormArray([
        
      ])
    });
  }

get medicineArray() {
    return this.medicinePurchaseForm.controls.purchaseMedicineList as FormArray;
}

addMedicinetoLine(){
    const purchasemedicine = new FormGroup({
          medicineId: new FormControl(this.medicineID.value, Validators.required),
          medicineName: new FormControl(this.brandName.value, Validators.required),
          unitPrice: new FormControl(this.price.value),
          quantity: new FormControl(this.quantity.value, Validators.required),
          itemTotal: new FormControl(),
    });
    this.medicineArray.push(purchasemedicine);
  }

Answer 1

试试这个，它应该在你的表单中实时计算...

HTML：

<mat-form-field appearance="fill">
    <mat-label>Quantity</mat-label>
    <input formControlName="quantity" (input)="calculateTotal()" matInput />
</mat-form-field>

<mat-form-field appearance="fill">
    <mat-label>Unit Price</mat-label>
    <input formControlName="unitPrice" (input)="calculateTotal()" matInput />
</mat-form-field>

<mat-form-field appearance="fill">
    <mat-label>Total</mat-label>
    <input formControlName="itemTotal" matInput />
</mat-form-field>

calculateTotal(): void {
    if(this.medicinePurchaseForm.get('unitPrice').value === null && this.medicinePurchaseForm.get('quantity').value === null) {
        this.medicinePurchaseForm.patchValue({
            itemTotal: 0.00
        });
    } else if (this.medicinePurchaseForm.get('unitPrice').value === null) {
        this.medicinePurchaseForm.patchValue({
            itemTotal: 0.00
        });
    } else if (this.medicinePurchaseForm.get('quantity').value === null) {
        this.medicinePurchaseForm.patchValue({
            itemTotal: 0.00
        });
    } else {
        this.medicinePurchaseForm.patchValue({
            itemTotal: +(this.medicinePurchaseForm.get('unitPrice').value) * +(this.medicinePurchaseForm.get('quantity').value)
        });
    }
}

问候