问当只有一个条件为真时，两个mat错误都会显示。
EN

Stack Overflow用户

提问于 2019-07-03 10:34:01

回答 2查看 4K关注 0票数 2

当只出现一个错误时，两个mat错误都会显示出来。

我正在尝试使用mat错误来定制验证器。当电子邮件和确认密码的真实值为hasError(‘)时，它们都是红色的。

我认为我的MyErrorStateMatcher类逻辑是错误的。请帮帮我！我已经尽我所能了。提前谢谢你！

图像

就像你在图像中看到的。当confirmPassword抛出错误时，电子邮件字段也是红色的。

我的ErrorStateMatcher：

export class MyErrorStateMatcher implements ErrorStateMatcher {
  isErrorState(control: FormControl | null, form: FormGroupDirective | NgForm | null): boolean {
    const invalidCtrl = !!(control && control.invalid && (control.dirty || control.touched));
    const invalidParent = !!(control && (control.parent.hasError('notTheSame') || control.parent.hasError('emailUsed')));

    return ((invalidCtrl || invalidParent));
  }
}

HTML：(关注电子邮件和confimPassword)

<form [formGroup]="signupForm" (ngSubmit)="signup(signupForm)">
        <mat-form-field style="width: 100%;">
          <input matInput formControlName="email" placeholder="Email address" type="email" [errorStateMatcher]="matcher" required>
          <mat-error *ngIf="signupForm.controls.email.hasError('required')">Email required!</mat-error>
          <mat-error *ngIf="signupForm.controls.email.hasError('email')">Email invalid!</mat-error>
          <mat-error *ngIf="signupForm.hasError('emailUsed')">This email already exists!</mat-error>
        </mat-form-field>
        <mat-form-field style="width: 100%;">
          <input matInput formControlName="username" placeholder="User name" (blur)="signupForm.value.username != null ? isValidUsername(signupForm.value.username) : ''" required />
          <mat-error>Please enter your new username!</mat-error>
          <mat-error *ngIf="usernameInvalid">Username already exists!</mat-error>
        </mat-form-field>
        <mat-form-field style="width: 100%;">
          <input matInput formControlName="password" placeholder="New password" [type]="show ? 'text' : 'password'" required />
          <mat-icon matSuffix (click)="show = !show" style="cursor: pointer;">{{show ? 'visibility' : 'visibility_off'}}</mat-icon>
          <mat-error>Please enter your password!</mat-error>
        </mat-form-field>
        <mat-form-field style="width: 100%;">
          <input matInput formControlName="confirmPassword" placeholder="Confirm password" type="password" [errorStateMatcher]="matcher" required>
          <mat-error *ngIf="signupForm.controls.confirmPassword.hasError('required')">Please confirm your password!</mat-error>
          <mat-error *ngIf="signupForm.hasError('notTheSame') && signupForm.value.confirmPassword != ''">Password is not the same!</mat-error>
        </mat-form-field>
        <br>
      <button mat-raised-button class="sessionBtn" color="primary" [disabled]="signupForm.invalid">Submit!</button>
</form>

TS：

signupForm = new FormGroup({
    firstName: new FormControl(),
    lastName: new FormControl(),
    email: new FormControl('', [
      Validators.required,
      Validators.email
    ]),
    username: new FormControl(),
    password: new FormControl('', [
      Validators.required
    ]),
    confirmPassword: new FormControl('', [
      Validators.required
    ])
  }, { validators: [this.checkPassword, this.checkExistingEmail] });
  matcher = new MyErrorStateMatcher();

/////////Custom validator////////

  checkPassword(signupForm: FormGroup) {
    let password = signupForm.value.password;
    let confirmPassword = signupForm.value.confirmPassword;

    return password === confirmPassword ? null : { notTheSame: true };
  }

  checkExistingEmail(signupForm: FormGroup) {
    let inputEmail = signupForm.value.email;
    let dbEmail = "test@test.com";

    return inputEmail !== dbEmail ? null: { emailUsed: true };
  }

错误发生在输入电子邮件和输入confirmPassword，两者都有[errorStateMatcher]="matcher"。

angular

typescript

angular-material

回答 2

Stack Overflow用户

回答已采纳

发布于 2019-07-04 09:34:07

创建customErrorMatcher

如果我们想在<mat-form-field>中显示一个错误，当input是有效的时，我们使用customErrorMatcher。

这是一个类似于

class CrossFieldErrorMatcher implements ErrorStateMatcher {
  isErrorState(control: FormControl | null, form: FormGroupDirective | NgForm | null): boolean {
    //when we want to show the error
    return true 
    //when we want not show the error
    return false
  }
}

正常情况下，我们有我们的组件

  errorMatcher=new CrossFieldErrorMatcher()
  //and the .html
  <mat-form-field>
    <input matInput formControlName='verifyPassword' 
        [errorStateMatcher]="errorMatcher">
    <mat-error *ngIf="....">
      Passwords do not match!
    </mat-error>
  </mat-form-field>

嗯，我们要稍微改变一下，在我们的customErrorMatcher中添加一个构造函数

class CrossFieldErrorMatcher implements ErrorStateMatcher {
  constructor(private name:string){}  //<--add a constructor
  isErrorState(control: FormControl | null, form: FormGroupDirective | NgForm | null): boolean {
    //when we want to show the error, but we can use "name"
    return true 
    //when we want not show the error
    return false
  }
}

然后，我们的组件变成

  errorMatcher(name:string)
  {
    return new CrossFieldErrorMatcher(name);
  }

  //and the .html
  <mat-form-field>
    <input matInput formControlName='verifyPassword' 
        [errorStateMatcher]="errorMatcher('password')">
    <mat-error *ngIf="....">
      Passwords do not match!
    </mat-error>
  </mat-form-field>