[英]@Output emit value from directive to parent component Angular 4
我有一些上傳指令,這很簡單,唯一的問題是我必須從這個指令組件向父組件發出值。 有人知道一個簡單的解決方案嗎? 提前致謝。 這是我現在的指示:
上傳-field.component.ts
import { Component, OnInit, Input } from '@angular/core';
import { TooltipModule } from 'ngx-bootstrap/tooltip';
@Component({
selector: 'app-upload-field',
templateUrl: './upload-field.component.html',
styleUrls: ['./upload-field.component.scss']
})
export class UploadFieldComponent implements OnInit {
@Input() labelName: string;
@Input() placeHolderValue: string;
value = '';
constructor() { }
ngOnInit() {
}
uploadButton(event: any) {
this.value += event.target.value;
this.value = this.value.replace(/^.*\\/, '');
}
}
上載field.component.html
<input placeholder="{{placeHolderValue}}" disabled="disabled" class="form-control first-input" value="{{value}}" />
<div class="file-upload">
<span class="btn btn-default btn-lg">{{labelName}}</span>
<input type="file" class="form-control upload-button" (change)="uploadButton($event)" value="{{value}}" />
</div>
我這樣使用它:
<app-upload-field [labelName]="'Blader'" [placeHolderValue]="'Kies bestand'"></app-upload-field>
您可以使用EventEmitter
。
參考: Parent偵聽子事件
import { Component, Output, EventEmitter } from '@angular/core';
@Component({
//...your decorator properties
})
export class UploadFieldComponent {
@Output() onValueChanged = new EventEmitter<any>();
uploadButton() {
this.value += event.target.value;
this.value = this.value.replace(/^.*\\/, '');
this.onValueChanged.emit(this.value);
}
}
在父組件中,模板:
<app-upload-field [labelName]="'Blader'" [placeHolderValue]="'Kies bestand'"
(onValueChanged)=onValueChanged($event)>
</app-upload-field>
在組件代碼中,
onValueChanged(value) {
// value will be the emitted value by the child
}
子組件公開一個
EventEmitter
屬性,當事情發生時,它會使用該屬性發出事件。 父級綁定到該事件屬性並對這些事件做出反應。
在UploadFieldComponent中
export class UploadFieldComponent implements OnInit {
...
@Output myValueChanged = new EventEmitter<string>();//passing a string value to parent
...
uploadButton(event: any) {
...
myValueChanged.emit(valueToBePassed);
}
}
用法
<app-upload-field [labelName]="'Blader'" (myValueChanged)="parentEvent($event)" [placeHolderValue]="'Kies bestand'"></app-upload-field>
在父組件中
parentEvent(data:string){
// do something with data
}
有關詳細信息,請參閱此鏈接。
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