angular-reactive-forms

问题 I want to make a student able to choose several workshops in a dynamic number of school subjects 1.- I have a config array, this array have the number of options of the student will choose for every subject let configarray = {initdate: 2019-07-01, subjectnumber: 4}; In this example for every subject the student will be able to choose 4 options. let b = this.FormGuardar.get("opciontaller") as FormArray; for (let i = 0; i < configarray.subjectnumber; i++) { let preregistro = this._fb.group({

问题 I have to find if one of my formcontrols has a pattern error. If it has a pattern error, then I have to change the value of that formcontrol to null. I wrote a recursive method that calls itself to check if one f the form control has a pattern error and then it finally returns true or false, But what I want is to change the value of that formcontrol to null Here is my recursive function, hasPatternError(form: AbstractControl, isRecursion = false): boolean { if (!isRecursion) { this

问题 i'm trying to get values from multiple checkbox here https://stackblitz.com/edit/angular-ivy-uahtjx i try this approach but didn't with for me https://stackblitz.com/edit/quiz-answer-value i think it's because the JSON schema is different, first one is array, and the second one is object. i set up my html like this <div *ngFor="let option of form.options"> <label><input (change)="onChange(i,j, form.code,check.checked)" #check [value]="answers[i].value.forms[j].answer.toString().indexOf(form

问题 i have used reactive forms, and the values are getting assigned to the html and the reactive forms is due to the array of object. So, what ever action i perform there must be used for comparing objects with the existing object. So i have used one array of object comparison method. But here the previous value is also getting binded to the new value which has been assigned to the form. I want the newly edited value and the old value as seperate so that i can compare if the object proerty values

问题 I'm working with a Reactive form and I have noticed in some tutorials they do the following: HTML . . <input type="text" formControlName="firstName" required> . . TS . . firstName: ['', Validators.required] . . QUESTION: Why do I need to specify "required" in the HTML if I just do it in the TS file it works fine? 回答1: Actually, Angular mention something about that here: Caution: Use these HTML5 validation attributes in combination with the built-in validators provided by Angular's reactive

问题 I have created a directive to focus an input if it's invalid import { Directive, Input, Renderer2, ElementRef, OnChanges } from '@angular/core'; @Directive({ // tslint:disable-next-line:directive-selector selector: '[focusOnError]' }) export class HighlightDirective implements OnChanges { @Input() submitted: string; constructor(private renderer: Renderer2, private el: ElementRef) { } ngOnChanges(): void { const el = this.renderer.selectRootElement(this.el.nativeElement); if (this.submitted &&

问题 In one of my requirements, I have form an array-like grid table contains rows and columns. once on Init i am doing a service call and get the columns and values and error messages. based on that i have created a form array for that columns and each columns have errormessage if errormessage exists need to set errors. I can able to set value for those columns but not able to set errors while pushing into form array i don't know how could I push error as well. stuck on this line. Qn? On

问题 Angular library I am trying to created a library for custom radio button with its role like warning(color yellow dot) error(color red dot) info(color blue dot) and success(color green dot) without angular library it will work fine, After that I move my css and template to library but now it is not work is expected I have provide value from reactive from but it does not check as expect I have also added screenshot at the end what I am expecting and what I get currently radio-button.html <label

问题 I am building a form group with an array inside of it, using mat-table data source. I started by creating the table: <form *ngIf="formGroup" [formGroup]="formGroup"> <table mat-table [dataSource]="dataSource" *ngIf="total>0" formArrayName="distribution"> <ng-container matColumnDef="ind_id"> <th mat-header-cell *matHeaderCellDef> ID </th> <td mat-cell *matCellDef="let element">{{element.individual_id}}</td> </ng-container> <ng-container matColumnDef="ind_name"> <th mat-header-cell

问题 I'm trying to calculate either discount percent or discount amount from list price using angular 6 reactive forms . form.component.html (simplified) ... <form [formGroup]="productForm"> <mat-form-field class="quat-width"> <span matPrefix>$  </span> <input matInput type="number" name="CostPrice" formControlName="CostPrice"> </mat-form-field> <mat-form-field class="quat-width"> <span matPrefix>$  </span> <input matInput type="number" name="ListPrice" formControlName="ListPrice"> </mat-form