无法在 Angular 2 中访问 addEventListener() 内的“this”上下文
在我的富文本编辑器组件中,我正在实现图像上传功能。 为此,我在图像输入标记中为“更改”编写了一个 addEventListener 事件处理程序,我需要通过“this”访问事件监听器内的应用程序服务。
Imageinput.addEventListener('change', () => {
const file = Imageinput.files[0];
var a = this;
if (Imageinput.files != null && Imageinput.files[0] != null) {
debugger;
this._imageUploadService.uploadImageToBlob(file).subscribe((res) => {
debugger;
this._returnedURL = res.imageUrl;
this.pushImageToEditor();
});
}
}
);
但是 this._imageUploadService 每次都返回 undefined,即使控制台没有任何错误。
<小时/>Here is my complete component.ts code -
export class CreateArticleComponent extends AppComponentBase {
@ViewChild("fileInput") fileInput;
public editor;
public _returnedURL = "";
constructor(
injector: Injector,
private _imageUploadService: ArticleServiceProxy,
) {
super(injector);
}
onEditorBlured(quill) {
console.log('editor blur!', quill);
}
onEditorFocused(quill) {
console.log('editor focus!', quill);
}
onEditorCreated(quill) {
console.log(quill);
let toolbar = quill.getModule('toolbar');
toolbar.addHandler('image', this.imageHandler);
//this.editorContent = quill;
this.editor = quill;
console.log('quill is ready! this is current quill instance object', quill);
}
imageHandler() {
debugger;
let self = this;
const Imageinput = document.createElement('input');
Imageinput.setAttribute('type', 'file');
//Imageinput.setAttribute('name', 'articleImage');
Imageinput.setAttribute('accept', 'image/png, image/gif, image/jpeg, image/bmp, image/x-icon');
Imageinput.classList.add('ql-image');
Imageinput.addEventListener('change', () => {
const file = Imageinput.files[0];
if (Imageinput.files != null && Imageinput.files[0] != null) {
debugger;
this._imageUploadService.uploadImageToBlob(file).subscribe((res) => {
debugger;
this._returnedURL = res.imageUrl;
this.pushImageToEditor();
});
}
}
);
Imageinput.click();
}
SendFileToServer(file: any) {
debugger;
this._imageUploadService.uploadImageToBlob(file).subscribe((res) => {
debugger;
this._returnedURL = res.imageUrl;
this.pushImageToEditor();
});
}
pushImageToEditor() {
debugger;
const range = this.editor.getSelection(true);
const index = range.index + range.length;
this.editor.insertEmbed(range.index, 'image', this._returnedURL);
}
ngAfterViewInit() {
}
}
<小时/>
Here is my editor HTML -
<quill-editor #fileInput
[(ngModel)]="editorContent"
[ngModelOptions]="{standalone: true}"
(onEditorCreated)="onEditorCreated($event)"
(onContentChanged)="onContentChanged($event)"
(onSelectionChanged)="logSelection($event)"
[style]="{'height':'300px'}">
</quill-editor>
我可以在其他方法中访问 this._imageUploadService
但无法在 addEventListener() 中访问它。任何帮助将不胜感激
最佳答案
在更改事件处理程序中 this
引用 toolbar.addHandler
的上下文,因此您需要它像这样绑定(bind) this.imageHandler
onEditorCreated(quill) {
console.log(quill);
let toolbar = quill.getModule('toolbar');
toolbar.addHandler('image', this.imageHandler.bind(this)); // <--
//this.editorContent = quill;
this.editor = quill;
console.log('quill is ready! this is current quill instance object', quill);
}
关于javascript - 无法访问 Angular 2 组件中 addEventListener() 中的 'this' 上下文,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/48986566/