Question

我正在将Angular 6与Angular Material一起使用。我正在尝试从mat-chip和自动完成功能中保存所选对象或所选对象的列表。我能够将字符串值发送到fruits []数组，但是无法将所选对象发送到fruits []数组。请帮助我找到解决方案。谢谢。

我的演示项目链接：demo code on stackblitz

Answer 1

我可以尝试使用此解决方案。

我已经在Stackblitz上创建了一个演示。

component.html

<mat-form-field class="example-chip-list">
    <mat-chip-list #chipList>
        <mat-chip *ngFor="let fruit of fruits;let indx=index;" [selectable]="selectable" [removable]="removable" (removed)="remove(fruit,indx)">
            {{fruit.name}}
            <mat-icon matChipRemove *ngIf="removable">cancel</mat-icon>
        </mat-chip>
        <input placeholder="New fruit..." #fruitInput [formControl]="fruitCtrl" [matAutocomplete]="auto" [matChipInputFor]="chipList"
         [matChipInputSeparatorKeyCodes]="separatorKeysCodes" [matChipInputAddOnBlur]="addOnBlur" (matChipInputTokenEnd)="add($event)">
    </mat-chip-list>
    <mat-autocomplete #auto="matAutocomplete" (optionSelected)="selected($event)">
        <mat-option *ngFor="let fruit of filteredFruits | async" [value]="fruit">
            {{fruit.name}}
        </mat-option>
    </mat-autocomplete>
</mat-form-field>


<pre>{{fruits|json}}</pre>

component.ts

import { COMMA, ENTER } from '@angular/cdk/keycodes';
import { Component, ElementRef, ViewChild } from '@angular/core';
import { FormControl } from '@angular/forms';
import { MatAutocompleteSelectedEvent, MatChipInputEvent } from '@angular/material';
import { Observable } from 'rxjs';
import { map, startWith } from 'rxjs/operators';

/**
 * @title Basic chips
 */
@Component({
  selector: 'chips-overview-example',
  templateUrl: 'chips-overview-example.html',
  styleUrls: ['chips-overview-example.css'],
})
export class ChipsOverviewExample {
  visible = true;
  selectable = true;
  removable = true;
  addOnBlur = false;
  separatorKeysCodes: number[] = [ENTER, COMMA];
  fruitCtrl = new FormControl();
  filteredFruits: Observable<string[]>;
  fruits: any = [];
  allFruits: any = [
    {
      id: 1,
      name: 'Apple'
    },
    {
      id: 2,
      name: 'Orange'
    },
    {
      id: 3,
      name: 'Banana'
    },
    {
      id: 4,
      name: 'Malta'
    }
  ];

  @ViewChild('fruitInput') fruitInput: ElementRef;

  constructor() {
    this.filteredFruits = this.fruitCtrl.valueChanges.pipe(
      startWith(null),
      map((fruit: string | null) => fruit ? this._filter(fruit) : this.allFruits.slice()));
  }

  add(event: MatChipInputEvent): void {
    const input = event.input;
    const value = event.value;
    // Add our fruit
    if ((value || '').trim()) {
      this.fruits.push({
          id:Math.random(),
          name:value.trim()
      });
    }

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

    this.fruitCtrl.setValue(null);
  }

  remove(fruit, indx): void {
    this.fruits.splice(indx, 1);
  }

  selected(event: MatAutocompleteSelectedEvent): void {
    this.fruits.push(event.option.value);
    this.fruitInput.nativeElement.value = '';
    this.fruitCtrl.setValue(null);
  }

  private _filter(value: any): string[] {
    return this.allFruits.filter(fruit => fruit.id === value.id);
  }
}

Answer 2

我一直在开发使用自动完成功能从列表中选择对象的应用程序。使用与克里希纳·拉索雷（Krishna Rathore）类似的方法，我发现FormControl valueChanges事件不能可靠地返回String（有时我得到了Object）。我的解决方案是添加一个Observable 并将其用于mat-autocomplete。我还添加了一个名为allowFreeTextAddEngineer的属性，以处理您的应用可能允许除自动完成列表中的条目之外的条目的情况。有一个Demo Here。

如何在角材2中使用垫片和自动完成功能保存所选对象

2 个答案: