Angular 12 - TypeError:无法读取 null 的属性(读取“writeValue”)
我正在创建一个通用文本输入组件,在为项目提供服务时一切正常,但在构建的项目中出现此错误:
TypeError:无法读取 null 的属性(读取“writeValue”)
HTML:
<div class="p-field">
<label>{{label}} <span class="p-error">{{checkRequired(ngControl.control) ? '*' : ''}}</span></label>
<input class="full-width" [type]="type" pInputText [formControl]="ngControl.control">
<small *ngIf="ngControl.control.touched && ngControl.control.errors?.required" class="p-error">{{label}} is required</small>
<small *ngIf="ngControl.control.errors?.minlength" class="p-error">
{{label}} must be at least {{ngControl.control.errors.minlength['requiredLength']}}
</small>
<small *ngIf="ngControl.control.errors?.maxlength" class="p-error">
{{label}} must be at most {{ngControl.control.errors.maxlength['requiredLength']}}
</small>
<small *ngIf="ngControl.control.errors?.email" class="p-error">
This email is not valid
</small>
<small *ngIf="ngControl.control.errors?.isMatching" class="p-error">Passwords do not match</small>
</div>
组件.ts
import { Component, Input, OnInit, Self } from '@angular/core';
import {AbstractControl, ControlValueAccessor, NgControl} from '@angular/forms';
@Component({
selector: 'app-text-input',
templateUrl: './text-input.component.html',
styleUrls: ['./text-input.component.css']
})
export class TextInputComponent implements ControlValueAccessor {
@Input() label: string;
@Input() type = 'text';
constructor(@Self() public ngControl: NgControl) {
this.ngControl.valueAccessor = this;
}
checkRequired(control) {
if (control.validator) {
const validator = control.validator({} as AbstractControl);
if (validator && validator.required) {
return true;
}
}
}
writeValue(obj: any): void {
}
registerOnChange(fn: any): void {
}
registerOnTouched(fn: any): void {
}
}
角度信息:
Angular CLI:12.2.6 节点:14.17.3 包管理器:npm 6.14.13 操作系统:win32 x64 Angular:12.2.6