viewchild

问题 What's the difference between ViewChild and ControlValueAccessor in Angular? Seems both of them can access child components, directives, DOM. So curious about the differences in usage, can one do something the other cannot do? 回答1: ControlValueAccesor is for making a custom form control . By steps, a FormControl can store anything, even an object. Imagine two different FormGroups form1=new FormGroup({ name:new FormControl('name') direcction:new FormControl({address:'address',cp:'cp'}) })

问题 What's the difference between ViewChild and ControlValueAccessor in Angular? Seems both of them can access child components, directives, DOM. So curious about the differences in usage, can one do something the other cannot do? 回答1: ControlValueAccesor is for making a custom form control . By steps, a FormControl can store anything, even an object. Imagine two different FormGroups form1=new FormGroup({ name:new FormControl('name') direcction:new FormControl({address:'address',cp:'cp'}) })

问题 What's the difference between ViewChild and ControlValueAccessor in Angular? Seems both of them can access child components, directives, DOM. So curious about the differences in usage, can one do something the other cannot do? 回答1: ControlValueAccesor is for making a custom form control . By steps, a FormControl can store anything, even an object. Imagine two different FormGroups form1=new FormGroup({ name:new FormControl('name') direcction:new FormControl({address:'address',cp:'cp'}) })

问题 What's the difference between ViewChild and ControlValueAccessor in Angular? Seems both of them can access child components, directives, DOM. So curious about the differences in usage, can one do something the other cannot do? 回答1: ControlValueAccesor is for making a custom form control . By steps, a FormControl can store anything, even an object. Imagine two different FormGroups form1=new FormGroup({ name:new FormControl('name') direcction:new FormControl({address:'address',cp:'cp'}) })

问题 I'm trying to access the nth child of a viewchildren querylist. Below is my TS: @ViewChildren(PopoverDirective) popovers: QueryList<PopoverDirective>; console.log(this.popovers) The console.log shows changes, first, last, length and _results. How can I access the nth child (i.e., 3rd, instead of first)? When I try to do this with _results (i.e., this.popovers._results[2]), I get an error. Thank you. 回答1: There are actually a couple of methods which you can access a particular inside you

问题 In my Angular application, my @ViewChild instance is failing to fill HTL matSort. mycomponent.ts: import { MatSort } from '@angular/material'; export class MyClassComponent { @ViewChild(MatSort) sort: MatSort; } ngOnInit() { console.log(this.sort); // undefined } mycomponent.html: <mat-table #table [dataSource]="dataSource" matSort> ....................................................... ....................................................... </mat-table> I need to use sortChange from matSort

问题 I'm trying to execute a function of a child component with a push of a button on the parent but for some reason its undefined. Parent: .. com1.html <ng-template #content let-c="close" let-d="dismiss"> <div class="modal-header"> <h4 class="modal-title">Title</h4> </div> <div class="modal-body" style="display: flex; justify-content: center;"> <app-com2 [var1]="value" #traceRef></app-com2> </div> <div class="modal-footer"> <button type="button" class="btn btn-outline-dark" (click)="savePNG()"><i

问题 is there a way to get the ViewContainerRef from a dynamic created component? My dynamic created component has an ngContent element inside, which i want to fill after the dynamic creation. export class Example { @ViewChild('content', { read: ViewContainerRef }) //normal way content: ViewContainerRef; ... ngAfterViewInit(){ let box1=this.content.createComponent(this.boxFactory); box1.instance.title="Dynamic (1)"; // HERE: the box1 has a ng-content area which i want to fill. } } I think about

问题 I have the dynamically generated textbox as below. <tr *ngFor="let item of data; let in=index"> <td> <input #unitNumber type="text" name="workPerformed-workcode-{{in}}" [(ngModel)] = "item.unitnumber" > </td> <td> <!-- Search option is given to chose the unit number----></td> </tr> Here, the search option is given to choose the unit number, if it has been chosen, then the corresponding textbox will be focused on using viewChildran. My try is @ViewChildren('unitNumber') enteredUnitNumbers; //

问题 I am using angular 5.2.0. I have a child component import { Component } from '@angular/core'; @Component({ template: `<div><\div>` }) export class ChildComponent { public childMethod() { ... } } and a parent component which accesses the child via ViewChild import { Component, ViewChild } from '@angular/core'; import { ChildComponent } from 'child.component'; @Component({ template: `<child-component #child><\child-component>` }) export class ParentComponent { @ViewChild('child') public child: