我正在处理登录表单，如果用户输入无效凭据，我们希望将电子邮件和密码字段都标记为无效，并显示登录失败的消息。我如何从一个可观察的回调设置这些字段无效?
模板:
<form #loginForm="ngForm" (ngSubmit)="login(loginForm)" id="loginForm">
<div class="login-content" fxLayout="column" fxLayoutAlign="start stretch">
<md-input-container>
<input mdInput placeholder="Email" type="email" name="email" required [(ngModel)]="email">
</md-input-container>
<md-input-container>
<input mdInput placeholder="Password" type="password" name="password" required [(ngModel)]="password">
</md-input-container>
<p class='error' *ngIf='loginFailed'>The email address or password is invalid.</p>
<div class="extra-options" fxLayout="row" fxLayoutAlign="space-between center">
<md-checkbox class="remember-me">Remember Me</md-checkbox>
<a class="forgot-password" routerLink='/forgot-password'>Forgot Password?</a>
</div>
<button class="login-button" md-raised-button [disabled]="!loginForm.valid">SIGN IN</button>
<p class="note">Don't have an account?<br/> <a [routerLink]="['/register']">Click here to create one</a></p>
</div>
</form>
登录方法:
@ViewChild('loginForm') loginForm: HTMLFormElement;
private login(formData: any): void {
this.authService.login(formData).subscribe(res => {
alert(`Congrats, you have logged in. We don't have anywhere to send you right now though, but congrats regardless!`);
}, error => {
this.loginFailed = true; // This displays the error message, I don't really like this, but that's another issue.
this.loginForm.controls.email.invalid = true;
this.loginForm.controls.password.invalid = true;
});
}
除了将输入无效标志设置为true之外，我还尝试设置电子邮件。valid标志为false，并设置loginForm。无效也为真。这些都不会导致输入显示其无效状态。
我试图在模板形式的ngModelChange处理程序中调用setErrors()。它没有工作，直到我用setTimeout()等待一个滴答:
模板:
<input type="password" [(ngModel)]="user.password" class="form-control"
id="password" name="password" required (ngModelChange)="checkPasswords()">
<input type="password" [(ngModel)]="pwConfirm" class="form-control"
id="pwConfirm" name="pwConfirm" required (ngModelChange)="checkPasswords()"
#pwConfirmModel="ngModel">
<div [hidden]="pwConfirmModel.valid || pwConfirmModel.pristine" class="alert-danger">
Passwords do not match
</div>
组件:
@ViewChild('pwConfirmModel') pwConfirmModel: NgModel;
checkPasswords() {
if (this.pwConfirm.length >= this.user.password.length &&
this.pwConfirm !== this.user.password) {
console.log('passwords do not match');
// setErrors() must be called after change detection runs
setTimeout(() => this.pwConfirmModel.control.setErrors({'nomatch': true}) );
} else {
// to clear the error, we don't have to wait
this.pwConfirmModel.control.setErrors(null);
}
}
像这样的陷阱让我更喜欢反应式。
我试图在模板形式的ngModelChange处理程序中调用setErrors()。它没有工作，直到我用setTimeout()等待一个滴答:
模板:
<input type="password" [(ngModel)]="user.password" class="form-control"
id="password" name="password" required (ngModelChange)="checkPasswords()">
<input type="password" [(ngModel)]="pwConfirm" class="form-control"
id="pwConfirm" name="pwConfirm" required (ngModelChange)="checkPasswords()"
#pwConfirmModel="ngModel">
<div [hidden]="pwConfirmModel.valid || pwConfirmModel.pristine" class="alert-danger">
Passwords do not match
</div>
组件:
@ViewChild('pwConfirmModel') pwConfirmModel: NgModel;
checkPasswords() {
if (this.pwConfirm.length >= this.user.password.length &&
this.pwConfirm !== this.user.password) {
console.log('passwords do not match');
// setErrors() must be called after change detection runs
setTimeout(() => this.pwConfirmModel.control.setErrors({'nomatch': true}) );
} else {
// to clear the error, we don't have to wait
this.pwConfirmModel.control.setErrors(null);
}
}
像这样的陷阱让我更喜欢反应式。
在我的反应式形式，我需要标记一个字段无效，如果另一个字段被选中。在ng版本7中，我做了以下工作:
const checkboxField = this.form.get('<name of field>');
const dropDownField = this.form.get('<name of field>');
this.checkboxField$ = checkboxField.valueChanges
.subscribe((checked: boolean) => {
if(checked) {
dropDownField.setValidators(Validators.required);
dropDownField.setErrors({ required: true });
dropDownField.markAsDirty();
} else {
dropDownField.clearValidators();
dropDownField.markAsPristine();
}
});
所以在上面，当我选中这个框时，它会根据需要设置下拉框，并将其标记为脏。如果您不这样标记它，那么直到您尝试提交表单或与之交互时，它才会无效(错误)。
如果复选框被设置为false(未选中)，那么我们清除下拉菜单上所需的验证器，并将其重置为原始状态。
另外，记得取消订阅监控字段更改!
