Question

如何验证mat-chip已添加到mat-chip-list。我正在使用ReactiveForms。我已经尝试过使用required验证程序。

该值可以是名称列表，因此在提交表单之前，我需要确保名称列表中至少有1个名称。如果列表为空，则mat-error将显示错误消息。使用required验证程序会使表单无效，无论向列表中添加名称如何。

编辑：反应形式

我试图制作一个自定义验证器，现在我使用的是响应式表单，而不是模板驱动的表单，但是我无法使其正常工作。我编辑了以下代码以反映所做的更改，并创建了此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

问题在于，当chipList的{{1}}的状态为{{1}时，errorState的{{1}}没有设置为true }。

我正面临着同样的问题，不知道为什么这不能立即解决，或者如何通过chipList的形式像FormArray那样隐式地实现。

作为解决方法，您可以从INVALID监听状态更改，并手动设置chipList的{{1}}：

FormArray

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

Answer 2

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

正在工作的Stackblitz链接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 3

不幸的是，无法使用Angular的任何预定义验证器，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 4

this example由mmalerba所证明，您可以使用两个单独的表单控件：一个用于mat-chip-list（这个应该是带有必需标志的一个），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

Angular 2+材料垫-芯片列表formArray验证

4 个答案: