我正在尝试根据此帖Angular 2 custom form input为角度2创建文件上传的自定义表单输入 但我跟随错误错误
zone.js:446未处理承诺拒绝:无法读取属性 'subscribe'未定义;区域:角;任务:Promise.then;值: TypeError:无法读取undefined(...)
的属性'subscribe'
我的代码是
import {
Component,
Directive,
EventEmitter,
Provider,
} from 'angular2/core';
import { NG_VALUE_ACCESSOR } from 'angular2/common';
import { CONST_EXPR } from 'angular2/src/facade/lang';
import { forwardRef } from 'angular2/src/core/di';
@Component({
selector: 'file-upload',
template: `<div
class="drop-zone"
(dragover)="dragover = true"
(dragleave)="dragover = false"
(drop)="handleFiles($event); $event.preventDefault();"
[ngClass]="{'dragover':dragover}"
>
Drop file here
</div>
<input type="file" (change)="handleFiles($event)" id="fileup"> <label for="fileup" class="button">Upload File</label>
<br>`,
styles: [require('./file-upload.component.sass')],
outputs: ['fileChange'],
})
export class FileUploadComponent {
constuctor() {
this.fileChange = new EventEmitter(false);
}
setValue(value) {
this.image = value;
}
handleFiles(event) {
event.preventDefault();
event.stopPropagation();
const files = event.target.files || event.dataTransfer.files;
const file = files[0];
const reader = new FileReader();
reader.onload = (e) => {
this.fileChange.emit(e.target.result);
};
reader.readAsBinaryString(file);
}
}
const CUSTOM_VALUE_ACCESSOR = CONST_EXPR(new Provider(
NG_VALUE_ACCESSOR, {
useExisting: forwardRef(() => FileUploadValueAccessor),
multi: true,
}));
@Directive({
selector: 'file-upload',
host: {
'(fileChange)': 'onChange($event)',
},
providers: [CUSTOM_VALUE_ACCESSOR],
})
export class FileUploadValueAccessor {
static get parameters() {
return [[FileUploadComponent]];
}
constructor(host) {
this.host = host;
this.onChange = () => {};
this.onTouched = () => {};
}
writeValue(value) {
this.host.setValue(value);
}
registerOnChange(fn) {
this.onChange = fn;
}
registerOnTouched(fn) {
this.onTouched = fn;
}
}
答案 0 :(得分:1)
我找到了解决方案,问题是我有一个错字“constuctor”应该是“构造函数”,因此输出fileChange没有定义。