I created a directive in Angular 6 named 'DeleteDirective' and reference to a service 'DeleteService' to make sure I can delete an item from my application. After the item is marked as deleted (in PHP back-end), I'll show an Undo element via the 'UndoComponent' that I dynamically added in the DeleteService. No problems so far.
#Directive({
selector: '[appDelete]'
})
export class DeleteDirective {
constructor(
#Inject(ViewContainerRef) viewContainerRef,
renderer: Renderer2
) {
service.renderer = renderer;
service.setRootViewContainerRef(viewContainerRef);
service.addUndoElement();
}
#HostListener('click') onClick() {
// (Some code to execute deletion)
this.deleteService.showUndoElement();
}
#Injectable({
providedIn: 'root'
})
export class DeleteService {
constructor(
rendererFactory: RendererFactory2,
private factoryResolver: ComponentFactoryResolver,
private appRef: ApplicationRef,
) {
this.renderer = rendererFactory.createRenderer(null, null);
this.factoryResolver = factoryResolver;
}
setRootViewContainerRef(viewContainerRef) {
this.rootViewContainer = viewContainerRef;
}
addUndoElement() {
const factory = this.factoryResolver.resolveComponentFactory(UndoComponent);
const component = factory.create(this.rootViewContainer);
// this.rootViewContainer.insert(component.hostView);
this.appRef.attachView(component.hostView);
const domElem = (component.hostView as EmbeddedViewRef<any>)
.rootNodes[0] as HTMLElement;
document.body.appendChild(domElem);
}
}
Now, in the UndoComponent HTML I created a link to undo the action, named restoreItem. I would like to use another service named ListService to get some data again.
#Injectable()
export class UndoComponent implements OnInit {
constructor(private listService: ListService) {
}
restoreItem() {
this.currentList = this.listService.getSelectedList();
console.log(this.currentList); // null
}
}
It seems I cannot reference to the ListService (or any other service) from this dynamically added component to the DOM. It returns null. Any ideas how I can access a service from a dynamically added Component? Thanks so much for any directions!
Edit: added Listservice stub code for clarification
#Injectable({
providedIn: 'root'
})
export class ListService {
lists: List[];
list: List[];
currentList: List;
constructor(private http: HttpClient) { }
setSelectedList(list: List): void {
this.currentList = list;
}
getSelectedList(): List {
return this.currentList;
}
private handleError(error: HttpErrorResponse) {
console.log(error);
return throwError('Error! something went wrong.');
}
}
Are you setting the value of currentList in ListService in anyway.
setSelectedList in ListService is never called which is being used to set value of currentList. So currentList remains null.
I am getting many errors at the dev tools console when adding a service into my component but the code still working but I want to get rid of from these errors
This's the service:
getPagesData(pageSlug: string): Observable<any[]> {
return this._http.get<any[]>(`${environment.apiUrl}wp/v2/pages/?slug=${pageSlug}`);
}
This is the component:
import { Component, OnInit } from '#angular/core';
import { DataService } from 'src/app/services/data.service';
#Component({
selector: 'app-membership',
templateUrl: './membership.page.html',
styleUrls: ['./membership.page.scss'],
})
export class MembershipPage implements OnInit {
public pageContent: any = {};
public content: string;
constructor(
private _data: DataService
) { }
ngOnInit() {
this._data.getPagesData('memberships')
.subscribe(
page => this.pageContent = page[0]
)
}
getContent(): string {
return this.pageContent.content.rendered.replace(/\[(.+?)\]/g, "");
}
}
What cause the errors is the getContent() method! it says that is the .rendered is an undefined property but it doses defined on the API!
I have searched on that problem and most of the solutions I found it's about using the symbol ? at HTML template but I can't use that in the component itself.
If you are calling getContent() in the HTML/template, you can most likely avoid this error by either:
Making pageContent initially null and using *ngIf to only display the content once it has asynchronously resolved:
Component:
public pageContent: any = null;
Template:
<div *ngIf="pageContent">{{getContent()}}</div>
Or you could instead RxJS operators such as map() and the async pipe:
Component:
import { Component, OnInit } from '#angular/core';
import { DataService } from 'src/app/services/data.service';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';
#Component({
selector: 'app-membership',
templateUrl: './membership.page.html',
styleUrls: ['./membership.page.scss'],
})
export class MembershipPage implements OnInit {
public pageContent: Observable<string>;
public content: string;
constructor(private _data: DataService) { }
ngOnInit() {
this.pageContent = this._data.getPagesData('memberships')
.pipe(
map(page => page[0].content.rendered.replace(/\[(.+?)\]/g, ""))
);
}
}
Template:
<div>{{pageContent | async}}</div>
That being said, you should probably have additional checks to ensure each sub-property is available prior to accessing it, but usually this type of error is because you are attempting to access the contents before they have resolved.
Hopefully that helps!
Yes, you cannot use ? Elvis (Safe navigation) operator in the component itself because it is designed for view part only.
But you can add some check in the component too to avoid such errors like -
getContent(): string {
const dataToReturn = this.pageContent && this.pageContent.content && this.pageContent.content.rendered.replace(/\[(.+?)\]/g, "");
return dataToReturn
}
.rendered is an undefined property
Also, This error may produce you have defined pageContent = {} so on {} neither content nor rendered exist , may be that is also the reason to exist such errors.
Angular recommend to strongly typecast your data before use.
In Angular 4 to dynamically create a component you can use ngComponentOutlet directive: https://angular.io/docs/ts/latest/api/common/index/NgComponentOutlet-directive.html
something like this:
Dynamic component
#Component({
selector: 'dynamic-component',
template: `
Dynamic component
`
})
export class DynamicComponent {
#Input() info: any;
}
App
#Component({
selector: 'my-app',
template: `
App<br>
<ng-container *ngComponentOutlet="component"></ng-container>
`
})
export class AppComponent {
this.component=DynamicComponent;
}
How do I pass #Input() info: any; information in this template <ng-container *ngComponentOutlet="component"></ng-container> ?
Such a feature was discussed in the pull request for ngComponentOutlet but was dropped for now.
Even the componentRef shown currently in https://angular.io/docs/ts/latest/api/common/index/NgComponentOutlet-directive.html is not public and therefore not available https://github.com/angular/angular/blob/3ef73c2b1945340ca6bd21f1790260c88698ae26/modules/%40angular/common/src/directives/ng_component_outlet.ts#L78
I'd suggest you create your own directive derived from https://github.com/angular/angular/blob/3ef73c2b1945340ca6bd21f1790260c88698ae26/modules/%40angular/common/src/directives/ng_component_outlet.ts#L72
and assign values to inputs like shown in Angular 2 dynamic tabs with user-click chosen components
this.compRef.instance.someProperty = 'someValue';
With the help of the post of #Günter Zöchbauer I solved a similar problem this way - I hope you can adapt it somehow.
First I defined some interfaces:
// all dynamically loaded components should implement this guy
export interface IDynamicComponent { Context: object; }
// data from parent to dynLoadedComponent
export interface IDynamicComponentData {
component: any;
context?: object;
caller?: any;
}
then I implemented them inside of the dynamically loaded component
dynamicLoadedComponentA.ts
// ...
export class DynamicLoadedComponentA implements IDynamicComponent {
// ...
// data from parent
public Context: object;
// ...
After that I built a new component which is responsible for the magic. Important here is that I had to register all dyn. loaded components as entryComponents.
dynamic.component.ts
#Component({
selector: 'ngc-dynamic-component',
template: ´<ng-template #dynamicContainer></ng-template>´,
entryComponents: [ DynamicLoadedComponentA ]
})
export class DynamicComponent implements OnInit, OnDestroy, OnChanges {
#ViewChild('dynamicContainer', { read: ViewContainerRef }) public dynamicContainer: ViewContainerRef;
#Input() public componentData: IDynamicComponentData;
private componentRef: ComponentRef<any>;
private componentInstance: IDynamicComponent;
constructor(private resolver: ComponentFactoryResolver) { }
public ngOnInit() {
this.createComponent();
}
public ngOnChanges(changes: SimpleChanges) {
if (changes['componentData']) {
this.createComponent();
}
}
public ngOnDestroy() {
if (this.componentInstance) {
this.componentInstance = null;
}
if (this.componentRef) {
this.componentRef.destroy();
}
}
private createComponent() {
this.dynamicContainer.clear();
if (this.componentData && this.componentData.component) {
const factory: ComponentFactory<any> = this.resolver.resolveComponentFactory(this.componentData.component);
this.componentRef = this.dynamicContainer.createComponent(factory);
this.componentInstance = this.componentRef.instance as IDynamicComponent;
// fill context data
Object.assign(this.componentInstance.Context, this.componentData.context || {});
// register output events
// this.componentRef.instance.outputTrigger.subscribe(event => console.log(event));
}
}
}
here the usage of this shiny new stuff:
app.html
<!-- [...] -->
<div>
<ngc-dynamic-component [componentData]="_settingsData"></ngc-dynamic-component>
</div>
<!-- [...] -->
app.ts
// ...
private _settingsData: IDynamicComponent = {
component: DynamicLoadedComponentA,
context: { SomeValue: 42 },
caller: this
};
// ...
I think for now you can use
https://www.npmjs.com/package/ng-dynamic-component
It is made specifically for this issue
So, What I am trying to do seems like it would be trivial. And it probably is. But I can't figure it out. My question is:How can I pass a variable from #Input to a service in an Angular2 component? (Code has been simplified)
My component is as follows:
import { Component, Input } from '#angular/core';
import { CMSService } from '../cms.service';
#Component({
selector: 'cmstext',
templateUrl: './cmstext.component.html',
styleUrls: ['./cmstext.component.css']
})
export class CMSTextComponent {
constructor(private cms: CMSService) { }
#Input() id : string;
content = this.cms.getContent(this.id); // this.id is NULL so content is NULL
}
And then my service:
import { Injectable } from '#angular/core';
#Injectable()
export class CMSService {
constructor() { }
getContent(textId:string) : string {
this.text = textId; // textId is NULL so this.text returns NULL
return this.text;
}
}
My component template:
<p>id: {{id}}</p>
<p>Content: {{content}}</p>
When <cmstext id="4"></cmstext> is added to another component template the output is:
id: 4
content:
I'm just diving into Angular2 any help or suggestions would be greatly appreciated!
Just make it a setter and put the code there:
#Input()
set id(value : string) {
this.content = this.cms.getContent(value);
}
As pointed out by #Kris Hollenbeck,ngOnInit() was the answer. My final code looked like this. The component now passed the variable to the service.
import { Component, Input, OnInit } from '#angular/core';
import { CMSService } from '../cms.service';
#Component({
selector: 'cmstext',
templateUrl: './cmstext.component.html',
styleUrls: ['./cmstext.component.css']
})
export class CMSTextComponent implements OnInit {
public content : string;
#Input() id : string;
constructor(private cms: CMSService) { }
ngOnInit() {
this.content = this.cms.getContent(this.id);
}
}
This assigned the data from the service to the variable "content" and the id passed from the element attribute to the variable "id". Both variables were then accessible to the template!
I want to manually compile some HTML containing directives. What is the equivalent of $compile in Angular 2?
For example, in Angular 1, I could dynamically compile a fragment of HTML and append it to the DOM:
var e = angular.element('<div directive></div>');
element.append(e);
$compile(e)($scope);
Angular 2.3.0 (2016-12-07)
To get all the details check:
How can I use/create dynamic template to compile dynamic Component with Angular 2.0?
To see that in action:
observe a working plunker (working with 2.3.0+)
The principals:
1) Create Template
2) Create Component
3) Create Module
4) Compile Module
5) Create (and cache) ComponentFactory
6) use Target to create an Instance of it
A quick overview how to create a Component
createNewComponent (tmpl:string) {
#Component({
selector: 'dynamic-component',
template: tmpl,
})
class CustomDynamicComponent implements IHaveDynamicData {
#Input() public entity: any;
};
// a component for this particular template
return CustomDynamicComponent;
}
A way how to inject component into NgModule
createComponentModule (componentType: any) {
#NgModule({
imports: [
PartsModule, // there are 'text-editor', 'string-editor'...
],
declarations: [
componentType
],
})
class RuntimeComponentModule
{
}
// a module for just this Type
return RuntimeComponentModule;
}
A code snippet how to create a ComponentFactory (and cache it)
public createComponentFactory(template: string)
: Promise<ComponentFactory<IHaveDynamicData>> {
let factory = this._cacheOfFactories[template];
if (factory) {
console.log("Module and Type are returned from cache")
return new Promise((resolve) => {
resolve(factory);
});
}
// unknown template ... let's create a Type for it
let type = this.createNewComponent(template);
let module = this.createComponentModule(type);
return new Promise((resolve) => {
this.compiler
.compileModuleAndAllComponentsAsync(module)
.then((moduleWithFactories) =>
{
factory = _.find(moduleWithFactories.componentFactories
, { componentType: type });
this._cacheOfFactories[template] = factory;
resolve(factory);
});
});
}
A code snippet how to use the above result
// here we get Factory (just compiled or from cache)
this.typeBuilder
.createComponentFactory(template)
.then((factory: ComponentFactory<IHaveDynamicData>) =>
{
// Target will instantiate and inject component (we'll keep reference to it)
this.componentRef = this
.dynamicComponentTarget
.createComponent(factory);
// let's inject #Inputs to component instance
let component = this.componentRef.instance;
component.entity = this.entity;
//...
});
The full description with all the details read here, or observe working example
.
.
OBSOLETE - Angular 2.0 RC5 related (RC5 only)
to see previous solutions for previous RC versions, please, search through the history of this post
Note: As #BennyBottema mentions in a comment, DynamicComponentLoader is now deprecated, hence so is this answer.
Angular2 doesn't have any $compile equivalent. You can use DynamicComoponentLoader and hack with ES6 classes to compile your code dynamically (see this plunk):
import {Component, DynamicComponentLoader, ElementRef, OnInit} from 'angular2/core'
function compileToComponent(template, directives) {
#Component({
selector: 'fake',
template , directives
})
class FakeComponent {};
return FakeComponent;
}
#Component({
selector: 'hello',
template: '<h1>Hello, Angular!</h1>'
})
class Hello {}
#Component({
selector: 'my-app',
template: '<div #container></div>',
})
export class App implements OnInit {
constructor(
private loader: DynamicComponentLoader,
private elementRef: ElementRef,
) {}
ngOnInit() {} {
const someDynamicHtml = `<hello></hello><h2>${Date.now()}</h2>`;
this.loader.loadIntoLocation(
compileToComponent(someDynamicHtml, [Hello])
this.elementRef,
'container'
);
}
}
But it will work only until html parser is inside angular2 core.
Angular Version I have Used - Angular 4.2.0
Angular 4 is came up with ComponentFactoryResolver to load components at runtime. This is a kind of same implementation of $compile in Angular 1.0 which serves your need
In this below example I am loading ImageWidget component dynamically in to a DashboardTileComponent
In order to load a component you need a directive that you can apply to ng-template which will helps to place the dynamic component
WidgetHostDirective
import { Directive, ViewContainerRef } from '#angular/core';
#Directive({
selector: '[widget-host]',
})
export class DashboardTileWidgetHostDirective {
constructor(public viewContainerRef: ViewContainerRef) {
}
}
this directive injects ViewContainerRef to gain access to the view container of the element that will host the dynamically added component.
DashboardTileComponent(Place holder component to render the dynamic component)
This component accepts an input which is coming from a parent components or you can load from your service based on your implementation. This component is doing the major role to resolve the components at runtime. In this method you can also see a method named renderComponent() which ultimately loads the component name from a service and resolve with ComponentFactoryResolver and finally setting data to the dynamic component.
import { Component, Input, OnInit, AfterViewInit, ViewChild, ComponentFactoryResolver, OnDestroy } from '#angular/core';
import { DashboardTileWidgetHostDirective } from './DashbardWidgetHost.Directive';
import { TileModel } from './Tile.Model';
import { WidgetComponentService } from "./WidgetComponent.Service";
#Component({
selector: 'dashboard-tile',
templateUrl: 'app/tile/DashboardTile.Template.html'
})
export class DashboardTileComponent implements OnInit {
#Input() tile: any;
#ViewChild(DashboardTileWidgetHostDirective) widgetHost: DashboardTileWidgetHostDirective;
constructor(private _componentFactoryResolver: ComponentFactoryResolver,private widgetComponentService:WidgetComponentService) {
}
ngOnInit() {
}
ngAfterViewInit() {
this.renderComponents();
}
renderComponents() {
let component=this.widgetComponentService.getComponent(this.tile.componentName);
let componentFactory = this._componentFactoryResolver.resolveComponentFactory(component);
let viewContainerRef = this.widgetHost.viewContainerRef;
let componentRef = viewContainerRef.createComponent(componentFactory);
(<TileModel>componentRef.instance).data = this.tile;
}
}
DashboardTileComponent.html
<div class="col-md-2 col-lg-2 col-sm-2 col-default-margin col-default">
<ng-template widget-host></ng-template>
</div>
WidgetComponentService
This is a service factory to register all the components that you want to resolve dynamically
import { Injectable } from '#angular/core';
import { ImageTextWidgetComponent } from "../templates/ImageTextWidget.Component";
#Injectable()
export class WidgetComponentService {
getComponent(componentName:string) {
if(componentName==="ImageTextWidgetComponent"){
return ImageTextWidgetComponent
}
}
}
ImageTextWidgetComponent(component we are loading at runtime)
import { Component, OnInit, Input } from '#angular/core';
#Component({
selector: 'dashboard-imagetextwidget',
templateUrl: 'app/templates/ImageTextWidget.html'
})
export class ImageTextWidgetComponent implements OnInit {
#Input() data: any;
constructor() { }
ngOnInit() { }
}
Add Finally add this ImageTextWidgetComponent in to your app module as entryComponent
#NgModule({
imports: [BrowserModule],
providers: [WidgetComponentService],
declarations: [
MainApplicationComponent,
DashboardHostComponent,
DashboardGroupComponent,
DashboardTileComponent,
DashboardTileWidgetHostDirective,
ImageTextWidgetComponent
],
exports: [],
entryComponents: [ImageTextWidgetComponent],
bootstrap: [MainApplicationComponent]
})
export class DashboardModule {
constructor() {
}
}
TileModel
export interface TileModel {
data: any;
}
Orginal Reference from my blog
Official Documentation
Download Sample Source Code
this npm package made it easier for me:
https://www.npmjs.com/package/ngx-dynamic-template
usage:
<ng-template dynamic-template
[template]="'some value:{{param1}}, and some component <lazy-component></lazy-component>'"
[context]="{param1:'value1'}"
[extraModules]="[someDynamicModule]"></ng-template>
In order to dinamically create an instance of a component and attach it to your DOM you can use the following script and should work in Angular RC:
html template:
<div>
<div id="container"></div>
<button (click)="viewMeteo()">Meteo</button>
<button (click)="viewStats()">Stats</button>
</div>
Loader component
import { Component, DynamicComponentLoader, ElementRef, Injector } from '#angular/core';
import { WidgetMeteoComponent } from './widget-meteo';
import { WidgetStatComponent } from './widget-stat';
#Component({
moduleId: module.id,
selector: 'widget-loader',
templateUrl: 'widget-loader.html',
})
export class WidgetLoaderComponent {
constructor( elementRef: ElementRef,
public dcl:DynamicComponentLoader,
public injector: Injector) { }
viewMeteo() {
this.dcl.loadAsRoot(WidgetMeteoComponent, '#container', this.injector);
}
viewStats() {
this.dcl.loadAsRoot(WidgetStatComponent, '#container', this.injector);
}
}
Angular TypeScript/ES6 (Angular 2+)
Works with AOT + JIT at once together.
I created how to use it here:
https://github.com/patrikx3/angular-compile
npm install p3x-angular-compile
Component: Should have a context and some html data...
Html:
<div [p3x-compile]="data" [p3x-compile-context]="ctx">loading ...</div>
You can see the component, that allow to compile simple dynamic Angular components https://www.npmjs.com/package/#codehint-ng/html-compiler
I know this issue is old, but I spent weeks trying to figure out how to make this work with AOT enabled. I was able to compile an object but never able to execute existing components. Well I finally decided to change tact, as I was't looking to compile code so much as execute a custom template. My thought was to add the html which anyone can do and loop though the existing factories. In doing so I can search for the element/attribute/etc. names and execute the component on that HTMLElement. I was able to get it working and figured I should share this to save someone else the immense amount of time I wasted on it.
#Component({
selector: "compile",
template: "",
inputs: ["html"]
})
export class CompileHtmlComponent implements OnDestroy {
constructor(
private content: ViewContainerRef,
private injector: Injector,
private ngModRef: NgModuleRef<any>
) { }
ngOnDestroy() {
this.DestroyComponents();
}
private _ComponentRefCollection: any[] = null;
private _Html: string;
get Html(): string {
return this._Html;
}
#Input("html") set Html(val: string) {
// recompile when the html value is set
this._Html = (val || "") + "";
this.TemplateHTMLCompile(this._Html);
}
private DestroyComponents() { // we need to remove the components we compiled
if (this._ComponentRefCollection) {
this._ComponentRefCollection.forEach((c) => {
c.destroy();
});
}
this._ComponentRefCollection = new Array();
}
private TemplateHTMLCompile(html) {
this.DestroyComponents();
this.content.element.nativeElement.innerHTML = html;
var ref = this.content.element.nativeElement;
var factories = (this.ngModRef.componentFactoryResolver as any)._factories;
// here we loop though the factories, find the element based on the selector
factories.forEach((comp: ComponentFactory<unknown>) => {
var list = ref.querySelectorAll(comp.selector);
list.forEach((item) => {
var parent = item.parentNode;
var next = item.nextSibling;
var ngContentNodes: any[][] = new Array(); // this is for the viewchild/viewchildren of this object
comp.ngContentSelectors.forEach((sel) => {
var ngContentList: any[] = new Array();
if (sel == "*") // all children;
{
item.childNodes.forEach((c) => {
ngContentList.push(c);
});
}
else {
var selList = item.querySelectorAll(sel);
selList.forEach((l) => {
ngContentList.push(l);
});
}
ngContentNodes.push(ngContentList);
});
// here is where we compile the factory based on the node we have
let component = comp.create(this.injector, ngContentNodes, item, this.ngModRef);
this._ComponentRefCollection.push(component); // save for our destroy call
// we need to move the newly compiled element, as it was appended to this components html
if (next) parent.insertBefore(component.location.nativeElement, next);
else parent.appendChild(component.location.nativeElement);
component.hostView.detectChanges(); // tell the component to detectchanges
});
});
}
}
If you want to inject html code use directive
<div [innerHtml]="htmlVar"></div>
If you want to load whole component in some place, use DynamicComponentLoader:
https://angular.io/docs/ts/latest/api/core/DynamicComponentLoader-class.html