我想动态创建一个模板。这应该用于在运行时构建ComponentType,并将其放置(甚至替换)到宿主组件内部的某个位置。
直到RC4我使用ComponentResolver,但与RC5我得到以下消息:
ComponentResolver is deprecated for dynamic compilation.
Use ComponentFactoryResolver together with @NgModule/@Component.entryComponents or ANALYZE_FOR_ENTRY_COMPONENTS provider instead.
For runtime compile only, you can also use Compiler.compileComponentSync/Async.
我找到了这个文档(Angular 2同步动态组件创建)
你要明白我可以用任何一种
一种带有ComponentFactoryResolver的动态ngIf。如果我在@Component({entryComponents: [comp1, comp2],…})内部传递已知的组件-我可以使用.resolveComponentFactory(componentToRender);
真正的运行时编译,使用编译器…
但问题是如何使用编译器?上面的说明说,我应该调用:Compiler.compileComponentSync/Async -那么如何?
为例。我想为一种设置创建(基于一些配置条件)这种模板
<form>
<string-editor
[propertyName]="'code'"
[entity]="entity"
></string-editor>
<string-editor
[propertyName]="'description'"
[entity]="entity"
></string-editor>
...
在另一种情况下,这个(字符串编辑器被文本编辑器取代)
<form>
<text-editor
[propertyName]="'code'"
[entity]="entity"
></text-editor>
...
等等(根据属性类型设置不同的数字/日期/引用编辑器,为某些用户跳过一些属性……)例如,这是一个例子,实际的配置可以生成更多不同和复杂的模板。
模板正在改变,所以我不能使用ComponentFactoryResolver和传递现有的…我需要一个解决方案与编译器。
2019年6月答案
好消息!看起来@angular/cdk包现在对门户提供了一流的支持!
在撰写本文时,我并没有发现上面的官方文档有什么特别的帮助(特别是在向动态组件发送数据和从动态组件接收事件方面)。总之,你需要:
步骤1)更新AppModule
从@angular/cdk/portal包中导入PortalModule,在entryComponents中注册你的动态组件
@NgModule({
declarations: [ ..., AppComponent, MyDynamicComponent, ... ]
imports: [ ..., PortalModule, ... ],
entryComponents: [ ..., MyDynamicComponent, ... ]
})
export class AppModule { }
步骤2。选项A:如果你不需要向动态组件传递数据和从动态组件接收事件:
@Component({
selector: 'my-app',
template: `
<button (click)="onClickAddChild()">Click to add child component</button>
<ng-template [cdkPortalOutlet]="myPortal"></ng-template>
`
})
export class AppComponent {
myPortal: ComponentPortal<any>;
onClickAddChild() {
this.myPortal = new ComponentPortal(MyDynamicComponent);
}
}
@Component({
selector: 'app-child',
template: `<p>I am a child.</p>`
})
export class MyDynamicComponent{
}
看看它的实际应用
步骤2。选项B:如果你确实需要向动态组件传递数据并从动态组件接收事件:
// A bit of boilerplate here. Recommend putting this function in a utils
// file in order to keep your component code a little cleaner.
function createDomPortalHost(elRef: ElementRef, injector: Injector) {
return new DomPortalHost(
elRef.nativeElement,
injector.get(ComponentFactoryResolver),
injector.get(ApplicationRef),
injector
);
}
@Component({
selector: 'my-app',
template: `
<button (click)="onClickAddChild()">Click to add random child component</button>
<div #portalHost></div>
`
})
export class AppComponent {
portalHost: DomPortalHost;
@ViewChild('portalHost') elRef: ElementRef;
constructor(readonly injector: Injector) {
}
ngOnInit() {
this.portalHost = createDomPortalHost(this.elRef, this.injector);
}
onClickAddChild() {
const myPortal = new ComponentPortal(MyDynamicComponent);
const componentRef = this.portalHost.attach(myPortal);
setTimeout(() => componentRef.instance.myInput
= '> This is data passed from AppComponent <', 1000);
// ... if we had an output called 'myOutput' in a child component,
// this is how we would receive events...
// this.componentRef.instance.myOutput.subscribe(() => ...);
}
}
@Component({
selector: 'app-child',
template: `<p>I am a child. <strong>{{myInput}}</strong></p>`
})
export class MyDynamicComponent {
@Input() myInput = '';
}
看看它的实际应用
对于这种特殊情况,使用指令动态创建组件将是更好的选择。
例子:
在您想要创建组件的HTML中
<ng-container dynamicComponentDirective [someConfig]="someConfig"></ng-container>
我将以以下方式处理和设计指令。
const components: {[type: string]: Type<YourConfig>} = {
text : TextEditorComponent,
numeric: NumericComponent,
string: StringEditorComponent,
date: DateComponent,
........
.........
};
@Directive({
selector: '[dynamicComponentDirective]'
})
export class DynamicComponentDirective implements YourConfig, OnChanges, OnInit {
@Input() yourConfig: Define your config here //;
component: ComponentRef<YourConfig>;
constructor(
private resolver: ComponentFactoryResolver,
private container: ViewContainerRef
) {}
ngOnChanges() {
if (this.component) {
this.component.instance.config = this.config;
// config is your config, what evermeta data you want to pass to the component created.
}
}
ngOnInit() {
if (!components[this.config.type]) {
const supportedTypes = Object.keys(components).join(', ');
console.error(`Trying to use an unsupported type ${this.config.type} Supported types: ${supportedTypes}`);
}
const component = this.resolver.resolveComponentFactory<yourConfig>(components[this.config.type]);
this.component = this.container.createComponent(component);
this.component.instance.config = this.config;
}
}
所以在你的组件中,文本,字符串,日期,任何你在HTML中传递的ng-container元素的配置都是可用的。
配置yourConfig可以是相同的,并定义您的元数据。
根据您的配置或输入类型,该指令应相应执行,并从受支持的类型中呈现适当的组件。如果不是,它将记录一个错误。
EDIT (26/08/2017): The solution below works well with Angular2 and 4. I've updated it to contain a template variable and click handler and tested it with Angular 4.3.
For Angular4, ngComponentOutlet as described in Ophir's answer is a much better solution. But right now it does not support inputs & outputs yet. If [this PR](https://github.com/angular/angular/pull/15362] is accepted, it would be possible through the component instance returned by the create event.
ng-dynamic-component may be the best and simplest solution altogether, but I haven't tested that yet.
@Long Field的答案是正确的!下面是另一个(同步)例子:
import {Compiler, Component, NgModule, OnInit, ViewChild,
ViewContainerRef} from '@angular/core'
import {BrowserModule} from '@angular/platform-browser'
@Component({
selector: 'my-app',
template: `<h1>Dynamic template:</h1>
<div #container></div>`
})
export class App implements OnInit {
@ViewChild('container', { read: ViewContainerRef }) container: ViewContainerRef;
constructor(private compiler: Compiler) {}
ngOnInit() {
this.addComponent(
`<h4 (click)="increaseCounter()">
Click to increase: {{counter}}
`enter code here` </h4>`,
{
counter: 1,
increaseCounter: function () {
this.counter++;
}
}
);
}
private addComponent(template: string, properties?: any = {}) {
@Component({template})
class TemplateComponent {}
@NgModule({declarations: [TemplateComponent]})
class TemplateModule {}
const mod = this.compiler.compileModuleAndAllComponentsSync(TemplateModule);
const factory = mod.componentFactories.find((comp) =>
comp.componentType === TemplateComponent
);
const component = this.container.createComponent(factory);
Object.assign(component.instance, properties);
// If properties are changed at a later stage, the change detection
// may need to be triggered manually:
// component.changeDetectorRef.detectChanges();
}
}
@NgModule({
imports: [ BrowserModule ],
declarations: [ App ],
bootstrap: [ App ]
})
export class AppModule {}
请访问http://plnkr.co/edit/fdP9Oc。