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我有一个自定义的验证程序来检查输入域空间属性的“错误”,但我不能明白,为什么输入字段被未定义的构造。Angular2/4无法绑定输入域ngControl - 不能读取的不确定
CustomValidationComponent:
import {Component} from '@angular/core';
import {FormControl, FormGroup, FormBuilder} from '@angular/forms';
import {UsernameValidators} from './usernameValidators';
@Component({
selector: 'custom-validation',
template: `
<div [formGroup]="usernameGroup">
<input type="text" placeholder="Name" formControlName="username">
<div *ngIf="username.errors.cannotContainSpace"> Without spaces! </div>
</div>
`
})
export class CustomValidationFormComponent {
usernameGroup: FormGroup;
constructor(fb: FormBuilder){
this.usernameGroup = fb.group({
username: ['', UsernameValidators.cannotContainSpace],
});
}
UsernameValidator:
import {FormControl} from '@angular/forms';
export class UsernameValidators {
static cannotContainSpace(control: FormControl){
if (control.value.indexOf(' ') >= 0)
return { cannotContainSpace: true };
return null;
}
}
你也可以只访问属性一样,直接usernameGroup.controls.username.errors?.cannotContainSpace –
你right..either方式工作。 –
谢谢@suraj,我贴在与所述溶液编辑 –