Angular 2+ material mat-chip-list formArray验证

Question

如何验证 mat-chip 已添加到 mat-chip-list。我正在使用 ReactiveForms。我已经尝试使用 required 验证器。

该值可以是一个姓名列表，因此在提交表单之前，我需要确保我的姓名列表中至少有 1 个姓名。如果列表为空，则 mat-error 应显示错误消息。使用 required 验证器会使表单无效，无论是否将名称添加到列表中。

编辑：反应形式

我已经尝试制作一个自定义验证器，我现在使用的是响应式表单而不是模板驱动的表单，但我无法让它工作。我编辑了以下代码以反映我的更改，并且我创建了这个 https://stackblitz.com/edit/angular-4d5vfj

HTML

<form [formGroup]="myForm">
  <mat-form-field class="example-chip-list">
    <mat-chip-list #chipList formArrayName="names">
      <mat-chip *ngFor="let name of myForm.get('names').controls; let i=index;"
        [formGroupName]="i"
        [selectable]="selectable"
        [removable]="removable"
        (removed)="remove(myForm, i)">
        <mat-icon matChipRemove *ngIf="removable">cancel</mat-icon>
      </mat-chip>

       <input placeholder="Names"
          [matChipInputFor]="chipList"
          [matChipInputSeparatorKeyCodes]="separatorKeysCodes"
          [matChipInputAddOnBlur]="addOnBlur"
          (matChipInputTokenEnd)="add($event, asset)">
    </mat-chip-list>
    <mat-error>Atleast 1 name need to be added</mat-error>
  </mat-form-field>
</form>

TS

import {COMMA, ENTER} from '@angular/cdk/keycodes';
import {Component} from '@angular/core';
import {FormGroup, FormControl, FormBuilder, FormArray} from '@angular/forms';
import {MatChipInputEvent} from '@angular/material';

@Component({
  selector: 'chip-list-validation-example',
  templateUrl: 'chip-list-validation-example.html',
  styleUrls: ['chip-list-validation-example.css'],
})
export class ChipListValidationExample {
  public myForm: FormGroup;

  // name chips
  visible = true;
  selectable = true;
  removable = true;
  addOnBlur = true;
  readonly separatorKeysCodes: number[] = [ENTER, COMMA];

  // data
  data = {
    names: ['name1', 'name2']
  }

  constructor(private fb: FormBuilder) {
    this.myForm = this.fb.group({
      names: this.fb.array(this.data.names, this.validateArrayNotEmpty)
    });
  }

  initName(name: string): FormControl {
    return this.fb.control(name);
  }

  validateArrayNotEmpty(c: FormControl) {
    if (c.value && c.value.length === 0) {
      return { 
        validateArrayNotEmpty: { valid: false }
      };
    }
    return null;
  }

  add(event: MatChipInputEvent, form: FormGroup): void {
    const input = event.input;
    const value = event.value;

    // Add name
    if ((value || '').trim()) {
      const control = <FormArray>form.get('names');
      control.push(this.initName(value.trim()));
      console.log(control);
    }

    // Reset the input value
    if (input) {
      input.value = '';
    }
  }

  remove(form, index) {
    console.log(form);
    form.get('names').removeAt(index);
  }
}

Answer 1

问题是当 chipList 的 FormArray 状态为 INVALID 时，chipList 的 errorState 未设置为 true。

我面临同样的问题，不知道为什么这不是开箱即用的，也不知道如何通过 chipList 的形式隐式实现 FormArray.

作为解决方法，您可以从 FormArray 监听状态变化并手动设置 chipList 的 errorState：

@ViewChild('chipList') chipList: MatChipList;

ngOnInit() {
  this.myForm.get('names').statusChanges.subscribe(
    status => this.chipList.errorState = status === 'INVALID'
  );
}

https://stackblitz.com/edit/angular-4d5vfj-gywxjz

Answer 2

遗憾的是，无法使用任何 Angular 的预定义验证器，因为它们并非设计用于数组。我在这篇文章的帮助下设法做到了：

https://www.dev6.com/Angular_Material_Chips_with_Reactive_Forms_and_Custom_Validation

Answer 3

为了能够在 mat-chip-list 上进行验证，我们必须将 mat-input 和 mat-chip-list 绑定为相同的 FormControl，如下所示

工作 Stackblitz link here

<form [formGroup]='group'>
  <mat-form-field class="example-chip-list">
    <mat-chip-list #chipList
                   required
                   formControlName="newFruit">
      <mat-chip *ngFor="let fruit of fruits"
                (removed)="remove(fruit)">
        {{fruit.name}}
        <mat-icon matChipRemove>cancel</mat-icon>
      </mat-chip>
      <input placeholder="New fruit..."
            formControlName="newFruit"
            [matChipInputFor]="chipList"
            [matChipInputSeparatorKeyCodes]="separatorKeysCodes"
            [matChipInputAddOnBlur]="addOnBlur"
            (matChipInputTokenEnd)="add($event)" required>
    </mat-chip-list>
      <!-- add mat-error  -->
    <mat-error *ngIf="group.controls.newFruit.hasError('required')">required!</mat-error>
  </mat-form-field>
</form>

Answer 4

正如 this example by mmalerba 所示，您可以使用两个单独的表单控件：一个用于 mat-chip-list（这个应该是带有所需标志的那个），另一个用于输入。有趣的是，您必须在 addEvent:

上手动设置两者的值

<!-- ... -->
    <mat-chip-list #chipList formControlName="names" required>
    <!-- ... -->
    <input placeholder="Names"
        [formControlName]="name"
        [matChipInputFor]="chipList"
        [matChipInputSeparatorKeyCodes]="separatorKeysCodes"
        [matChipInputAddOnBlur]="addOnBlur"
        (matChipInputTokenEnd)="add($event, asset)">
    </mat-chip-list>
    <!-- ... -->

import {Validators} from '@angular/forms';

    # ...
    constructor(private fb: FormBuilder) {
        this.myForm = this.fb.group({
            names: [this.data.names, Validators.required],
            name: ['']
        });
    }

    # ...
    add(event: MatChipInputEvent, form: FormGroup): void {
      const input = event.input;
      const value = event.value;

      // Add name
      if ((value || '').trim()) {
        const control = <FormArray>form.get('names');
        control.push(this.initName(value.trim()));
        console.log(control);
      }

      // Reset the input value
      if (input) {
        input.value = '';
      }

      // update form control (necessary for correct validation)
      this.myForm.controls.name.setValue(null);
      this.myForm.controls.names.setValue(this.data.names);
    }

    # ...
}

这是他们的 stackblitz example

Answer 5

因为有人正面临这个问题。几个小时后，我找到了问题的根本原因和解决方案：

在 chiplist 的添加、删除、select 函数中，您需要使用反应形式的函数 setValue 来使验证工作。

例如：

  this.form.get('names').value.push('abc');
  this.form.get('names').setValue(this.form.get('names').value); // => this line of code will make the validation work

Angular 2+ material mat-chip-list formArray验证

Angular 2+ material mat-chip-list formArray validation

angular2-forms

angular-material2

angular

angular-reactive-forms