Question

我正在尝试创建联系表单。表格如下：

<form novalidate [formGroup]="contact" (ngSubmit)="send()">
  <p>
    <label>Name
      <br>
      <input type="text" class="input" value="" formControlName="name">
      <span class="error">Enter your name</span>
    </label>
  </p>
  <p>
    <label>E-mail
      <br>
      <input type="email" class="input" value="" formControlName="email">
      <span class="error">It looks like this email is invalid</span>
    </label>
  </p>
  <p>
    <label>Phone
      <br>
      <input type="text" class="input" value="" formControlName="telefone">
      <span class="error">It looks like this phone number is invalid</span>
    </label>
  </p>
  <p>
    <label>Message
      <br>
      <textarea type="text" class="input" value="" formControlName="message"></textarea>
      <span class="error">The message can't be empty</span>
    </label>
  </p>
  <p class="submit">
    <input type="submit" name="submit" class="bt" value="Send">
  </p>
</form>

在此表单中，只需要消息以及姓名和电子邮件或电话号码字段。

我使用的是formBuilder类，所以这里是TypeScript代码：

this.contact = this.formBuilder.group({
  name: ['', Validators.required],
  email: ['', Validators.compose([/*Use custom validador??*/])],
  phone: ['', Validators.compose([/*Use custom validador??*/]],
  message: ['', Validators.required]
});

我尝试使用自定义验证器作为解决方案，但我找不到解决方案。有什么建议吗？

Answer 1

我创建了一个自定义验证程序指令：

import {
    FormGroup,
    ValidationErrors,
    ValidatorFn,
    Validators,
  } from '@angular/forms';

  export const atLeastOne = (validator: ValidatorFn, controls:string[] = null) => (
    group: FormGroup,
  ): ValidationErrors | null => {
    if(!controls){
      controls = Object.keys(group.controls)
    }

    const hasAtLeastOne = group && group.controls && controls
      .some(k => !validator(group.controls[k]));

    return hasAtLeastOne ? null : {
      atLeastOne: true,
    };
  };

要使用它，您只需执行此操作：

this.form = this.formBuilder.group({
            name: ['', Validators.required],
            email:[''],
            telefone:[''],
            message:['', Validators.required],
        }, { validator: atLeastOne(Validators.required, ['email','telefone']) });

这里需要email或telefone。如果你把它留空，那么任何带有值的控件都可以，你可以将它用于任何类型的验证器，而不仅仅是Validators.required。

这可以任何形式重复使用。

Answer 2

是的，可以使用自定义验证器。

将您的表单组设为：

this.contact = this.formBuilder.group({
  name: ['', Validators.required],
  email: ['', Validators.required],
  phone: ['', Validators.required],
  message: ['', Validators.required]
}, {validator: this.customValidationFunction})

然后检查customValidationFunction验证。例如，制作验证：

customValidationFunction(formGroup): any {
   let nameField = formGroup.controls['name'].value; //access any of your form fields like this
   return (nameField.length < 5) ? { nameLengthFive: true } : null;
}

更改每个输入（将p标签更改为div。替换每个输入的控件名称，并在适当的情况下更改隐藏span标记验证的语法）：

<div [ngClass]="{'has-error':!contact.controls['name'].valid && contact.controls['name'].touched}">
    <label>Name</label>
    <input class="input" type="text" [formControl]="contact.controls['name']">
    <span [hidden]="!contact.hasError('nameLengthFive')" class="error">Enter your name</span>
</div>

Answer 3

我已更新验证程序片段以支持字符串和数字类型

我受到Todd Skelton的启发。这是一个非常简单的验证程序，它可以完成您所要的，而无需执行其他操作：

/**
 * Validates if at least one of the provided fields has a value.
 * Fields can only be of type number or string.
 * @param fields name of the form fields that should be checked
 */
export function atLeastOne(...fields: string[]) {
  return (fg: FormGroup): ValidationErrors | null => {
    return fields.some(fieldName => {
      const field = fg.get(fieldName).value;
      if (typeof field === 'number') return field && field >= 0 ? true : false;
      if (typeof field === 'string') return field && field.length > 0 ? true : false;
    })
      ? null
      : ({ atLeastOne: 'At least one field has to be provided.' } as ValidationErrors);
  };
}

这是我的用法：

  ngOnInit(): void {
    this.form = this.formBuilder.group(
      {
        field: [this.field],
        anotherField: [this.anotherField],
      },
      { validator: atLeastOne('field','anotherField') },
    );
  }

Answer 4

稍微重构了弗洛里安对懒惰的回答，因为它使ts-sonar生气（认知复杂性规则）：

const isFieldEmpty = (fieldName: string, fg: FormGroup) => {
    const field = fg.get(fieldName).value;
    if (typeof field === 'number') { return field && field >= 0 ? true : false; }
    if (typeof field === 'string') { return field && field.length > 0 ? true : false; }
};

export function atLeastOne(...fields: string[]) {
  return (fg: FormGroup): ValidationErrors | null => {
    return fields.some(fieldName => isFieldEmpty(fieldName, fg))
      ? null
      : ({ atLeastOne: 'At least one field has to be provided.' } as ValidationErrors);
  };
}

使用Angular 2从两个字段中需要一个

4 个答案: