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Angular - Focus on input element that has ngIf [duplicate]

This question already has answers here:
Focus an element after it appears via ngIf
(2 answers)
Closed 7 months ago.
I have two input elements that are shown under *ngIf conditions.
<input type="text" id="textInput" *ngIf="showTextInput">
<input type="number" id="numericInput" *ngIf="showNumericInput">
<button (click)="editButtonClicked($event)">
Clicking on the button should set focus to the appropriate input element.
editButtonClicked(event) {
// Focus on either #textInput or #numericInput element
}
I've looked into ElementRef to give the html input elements tags like #textInput and then define them on the class for example:
#ViewChild('textInput') textInput: ElementRef;
...but apparently this does not work on elements that have *ngIf conditionals.
How can I focus on an input element, onClick of a button?

You could implement a super simple directive and have the desired effect.
html
<input type="text" autoFocus *ngIf="isInputVisible">
directive
import { Directive, ElementRef, OnInit } from "#angular/core";
#Directive({
selector: "[autoFocus]"
})
export class AutoFocusDirective implements OnInit {
private inputElement: HTMLElement;
constructor(private elementRef: ElementRef) {
this.inputElement = this.elementRef.nativeElement;
}
ngOnInit(): void {
this.inputElement.focus();
}
}
Working Demo:
https://stackblitz.com/edit/angular-ivy-vvgcch?file=src%2Fapp%2Fdirectives%2Fauto-focus.directive.ts

Yes #ViewChild will not work for elements who are under the control of a structural directive. There are two workaround that you can apply:
Remove the *ngIf directive and hide the element using CSS style: 'display:none'.
Select the element from the DOM using vanilla Javascript document.getElementById('someId'); and then focus the element.
I will prefer point 1.

you can also do this by template reference variable if that's what you are looking for
in html
<input #text type="text" id="textInput">
<input #number type="number" id="numericInput">
<button (click)="editButtonClicked($event, text, number)"> Click </button>
in ts
editButtonClicked(e, text, number){
if(text.value) {
text.focus()
} else {
number.focus()
}
}

nativeElement select wait for binding data

Let's say that I have a child component called inputComponent that has a single input element as follow
#Component({ template: `<input #count [(ngModel)]="item.count" />`})
export class inputComponent implements OnInit {
#Input item;
#ViewChild("count") count : ElementRef ;
focus(){
this.count.nativeElement.focus();
this.count.nativeElement.select();
}
}
and I'm including it in a parent container as follow
<app-input-component [item]="item" ></app-input-component>
What I'm trying to achieve is to select the text input on a certain event.
for example
#ViewChild("input") count : inputComponent ;
foo(){
this.item = item ;
this.count.focus();
}
The problem is when I call focus change right after changing the binding data (item) it doesn't select anything hover if I called focus() after a short timeout it works perfectly .
I know it's not the proper way to use setTimeOut to solve it.
Stackblitz url
https://stackblitz.com/edit/angular-svgmtg

Apparently, ngModel updates the view's value asynchronously when the model is changed. I.e. the <input> value is not changed until the next change detection cycle!
From the ngModel source code:
/**
* `ngModel` forces an additional change detection run when its inputs change:
* E.g.:
* ```
* <div>{{myModel.valid}}</div>
* <input [(ngModel)]="myValue" #myModel="ngModel">
* ```
* I.e. `ngModel` can export itself on the element and then be used in the template.
* Normally, this would result in expressions before the `input` that use the exported directive
* to have and old value as they have been
* dirty checked before. As this is a very common case for `ngModel`, we added this second change
* detection run.
*
* Notes:
* - this is just one extra run no matter how many `ngModel` have been changed.
* - this is a general problem when using `exportAs` for directives!
*/
const resolvedPromise = Promise.resolve(null);
Then when the model is updated, the view is updated asynchronously:
private _updateValue(value: any): void {
resolvedPromise.then(
() => { this.control.setValue(value, {emitViewToModelChange: false}); });
}
So the setTimeout ensured that the input was selected after its view was updated.
If you want to avoid this asynchronous behavior, you can use FormControl instead of ngModel (Demo StackBlitz):
import { Component, Input, ViewChild, ElementRef } from '#angular/core';
import { FormControl } from '#angular/forms';
#Component({
selector: 'hello',
template: `<input #input [formControl]="count" />`,
styles: [`h1 { font-family: Lato; }`]
})
export class HelloComponent {
private _item;
#Input() set item(value) {
this._item = value;
this.count.setValue(value.count);
this.focus();
}
get item() {
return this._item;
}
#ViewChild('input') input: ElementRef;
count = new FormControl();
focus() {
this.input.nativeElement.focus();
this.input.nativeElement.select();
}
}
With this approach, you don't need to call focus() explicitly from the parent component; the child component will call its own focus method whenever the input changes.

As I understood, you trying to get an element before it has been rendered. That is impossible.
I advice you to read about Lifecycle hooks in Angular. https://angular.io/guide/lifecycle-hooks
You can solve this problem, calling your foo() function in lifecycle hook - ngAfterViewInit.
ngAfterViewInit() {
this.foo();
}

Angular 2/Typescript Delete Object On Button Click

I have an Angular 2 app using Typescript but i am new to this, what i have is a table with a 'Delete' button,
I can pass the object data to my confirmation modal but when i 'Confirm' it, its still in my table.
delete-modal.component
import { Component, OnInit, Inject, Input } from '#angular/core';
import { TestService } from '../../ABC/TestService/TestService.service';
import { MdDialog, MdDialogRef, MD_DIALOG_DATA } from '#angular/material';
import { testModal } from 'models/test';
#Component({
selector: 'app-test',
templateUrl: './test.component.html',
styleUrls: ['./test.css']
})
export class testDeleteModalComponent implements OnInit {
#Input('test') test: testModal;
constructor(private TestService: TestService, private accountService: AccountService,
#Inject(MD_DIALOG_DATA) private dialogData: any) { }
ngOnInit() {
console.log('test', this.dialogData.beneficiary);
this.test = this.dialogData.test;
}
deleteTest() {
if (this.dialogData.test.identifier) {
// this.dialogData.beneficiary.splice(this.dialogData.beneficiary.indexOf(this.beneficiaryAnt), 1);
// this.dialogData.beneficiary.splice(this.beneficiary);
// delete this.beneficiary;
this.dialogData.test.splice(this.dialogData.test.indexOf(this.dialogData.test), 1);
} else {
this.dialogData.test.operation = 'X';
}
}
}
HTML
<button md-icon-button (click)="deleteTest()" name="deleteTestDetails">
<md-icon>delete forever</md-icon>
</button>
All other HTML is in a main component and the 'Delete' button is used as shown below
<app-test-main-page-delete-button [test]="test"></app-test-main-page-delete-button>
The 'deleteTest' method is called when the user click the confirm button.
I have also included above some ways i have tried in the IF but they always come back
... is not a function

It is good that you asked this question, my projects of three peoples also struggling with this. we have found is two ways. what i will show is two ways of doing typescriptdelete.
solution a.
because it is object, it will need identifier. First is
var objectdelete = {
identifier: 'Mydelte',
value: '168%'
}
Next what we need is now service. some people call them directives but from my experience they are the same thing. We have alert so user knows if they did not set identifier that they must go back. I do not see service on your side, i see array being deleted. if you combine the array and the service, this will then be working across whole website.
export class DeleteService
delete(objectToDelete: string) {
if (!objectToDelete.identifier) {
alert('No identifer');
}else {
// Delete from your array here.
}
}
Solution 2.
If the above does not meed your needs, our tema also experimented with interfaces in typescript. You can see them here https://www.typescriptlang.org/docs/handbook/interfaces.html
so it becomes
export class myDeleteService {
deleter: IDeleter
}
export interface IDeleter {
delete: this.delete.delete(deletE);
deleteArray: this.array =[];
}
then simply in your html it will be
<button (click)='delete(dieleter)'>Delete me!</button>
These are all common typescript behaviours for angular2/4/5 so we are hoping to become more used to them when we have hads more time to use them!

The easiest way to delete data object on button click and refresh instantly when it's done :
Your parent html has to call children like this :
<app-component [inputData]="dataTable" (inputDataChange)="resetData()"/>
Add dataTable as class variable and implement the output function :
resetData() { this.dataTable=[] }
Then in children html leave your code (you can use this changes)
<button class="fa fa-delete" (click)="deleteTest()" name="deleteTestDetails">Delete</button>
Finaly in your children ts file set your data object for each change, and implement your input function
myDataTable: any = [];
#Input set inputData(data: DataTable) {
if(data) {
this.myDataTable = data;
}}
#Output() inputDataChange: EventEmitter<any> = new EventEmitter();
deleteTest() {
this.inputDataChange.emit(true);
}
What does this code do ?
It will emit and event to the parent when the delete button is clicked, then your parent will delete the dataTable, and finally, your children input will refresh it, as setter will catch the changes and refresh the variable.
If you want to apply those rules to table changes, then simply emit your dataTable and reassign it instead of reset it.

I am in a project with and our team have struggled on this for a whiles.
First thing I will say is this, Angular has not made this an easy task, so we will attempt to ignore the framework and write pure Java instead to make our lives easyer on ourselves.
SO looking at your button, I can see that you have started on the right track.
If the button is calling your component like the following
Html/Java
<button ng-click="delete()">Click me<button>
Component.ts
function delete = deleteMethod(testIdentifier) {
var abc = this.beneficiary.beneficiaryIdentifier.test.splice(this.beneficiary.beneficiaryIdentifier.test.indexOf(testIdentifier));
component2.deleteFunction();
}
Component2.ts
Then we can pass our identifiers into our parent or child components and remove the beneficiary like so:
deleteMethod(deetle) {
this.beneficiary.removeAtIndex(testIdentifier.splice(1), 1);
}
Nice and easy looking back, but it took our team of threes a long whiles to figure that ones out.

Angular 4 Change form input value to # while tying

I am trying to mimic what is done with passwords, where whatever an user types, it is substituted by •••••••, except that I want to do this for numbers and only show the last four numbers. So far I have the events in my #Directive that capture the keystrokes, but don't actually emit or propagate any change up the stream (in the input) to change the value.
Ex. #####1234
<input id="indTaxId" type="text" name="indTaxId"
[(ngModel)]="payLoadService.individual.taxId"
required maxlength="9" pattern="^[0-9]{9}$"
[lastFourDirective]="payLoadService.individual.taxId"
(lastFourDirectiveOutput)="payLoadService.individual.taxId"
/>
last-four.directive.ts
#Directive({
selector: '[lastFourDirective]'
})
export class LastFourDirective implements OnInit {
private el: HTMLInputElement;
constructor(
private elementRef: ElementRef
) {
this.el = this.elementRef.nativeElement;
}
ngOnInit() {
}
#Input() lastFourDirective: string;
#HostListener('blur', ['$event.target.value'])
onBlur(value) {
console.log("blur", value);
return this.lastFourDigits(value)
}
#HostListener('keyup', ['$event.target.value'])
onKeyup(value) {
console.log("keyup", value);
return this.lastFourDigits(value)
}
private lastFourDigits(taxId: string) {
return taxId.replace(/\d(?=\d{4})/g, '#')
}
}
How can I accomplish this?
PS: I'm not using formControl, above is a sample of my input.

You are using a directive so certainly there is a global need for you to do this in your application. I haven't worked on angular4 (I really thought, somehow I could use a filter here but was unable) but if there isn't a global need for this kind of input box, why don't you write a function in your component itself and trigger it on (keyup) and (blur) events. For example:
<input id="indTaxId" type="text" name="indTaxId"
[(ngModel)]= payLoadService.individual.taxId
required maxlength="9" pattern="^[0-9]{9}$"
(keyup)="foo()"
(blur)="foo()"
/>
and in your component:
foo() {
this.payLoadService.individual.taxId = this.payLoadService.individual.taxId.replace(/\d(?=\d{4})/g, '#');
}
Now I don't have an answer if you want to implement through a directive, but I can suggest you another solution if you want this functionality at multiple places, you can make a password input component containing only this functionality i.e. only the input box and use this component wherever you want such input boxes.

How do I detect change to ngModel on a select tag (Angular 2)?

I am attempting to detect a change on ngModel in a <select> tag. In Angular 1.x, we might solve this with a $watch on ngModel, or by using ngChange, but I've yet to understand how to detect a change to ngModel in Angular 2.
Full Example: http://plnkr.co/edit/9c9oKH1tjDDb67zdKmr9?p=info
import {Component, View, Input, } from 'angular2/core';
import {FORM_DIRECTIVES} from 'angular2/common';
#Component({
selector: 'my-dropdown'
})
#View({
directives: [FORM_DIRECTIVES],
template: `
<select [ngModel]="selection" (ngModelChange)="onChange($event, selection)" >
<option *ngFor="#option of options">{{option}}</option>
</select>
{{selection}}
`
})
export class MyDropdown {
#Input() options;
selection = 'Dog';
ngOnInit() {
console.log('These were the options passed in: ' + this.options);
}
onChange(event) {
if (this.selection === event) return;
this.selection = event;
console.log(this.selection);
}
}
As we can see, if we select a different value from the dropdown, our ngModel changes, and the interpolated expression in the view reflects this.
How do I get notified of this change in my class/controller?

Update:
Separate the event and property bindings:
<select [ngModel]="selectedItem" (ngModelChange)="onChange($event)">
onChange(newValue) {
console.log(newValue);
this.selectedItem = newValue; // don't forget to update the model here
// ... do other stuff here ...
}
You could also use
<select [(ngModel)]="selectedItem" (ngModelChange)="onChange($event)">
and then you wouldn't have to update the model in the event handler, but I believe this causes two events to fire, so it is probably less efficient.
Old answer, before they fixed a bug in beta.1:
Create a local template variable and attach a (change) event:
<select [(ngModel)]="selectedItem" #item (change)="onChange(item.value)">
plunker
See also How can I get new selection in "select" in Angular 2?

I have stumbled across this question and I will submit my answer that I used and worked pretty well. I had a search box that filtered and array of objects and on my search box I used the (ngModelChange)="onChange($event)"
in my .html
<input type="text" [(ngModel)]="searchText" (ngModelChange)="reSearch(newValue)" placeholder="Search">
then in my component.ts
reSearch(newValue: string) {
//this.searchText would equal the new value
//handle my filtering with the new value
}