选择后清除角度材料自动完成

Question

我遇到的问题如下:我需要的行为是,当从自动完成输入中选择一个选项时,它应该向Angular Material Chips组件添加一个芯片(它会这样做),它还应该清除自动完成输入,那么我可以选择其他选项.

这是我的HTML:

<div class="col-md-6">
  <md-form-field>
    <input type="text" placeholder="Categoría" aria-label="Categoría" mdInput [mdAutocomplete]="auto" [formControl]="categoryCtrl">
    <md-autocomplete #auto="mdAutocomplete" (optionSelected)="selectCategory($event)">
      <md-option *ngFor="let category of filteredCategories | async" [value]="category.name">
        {{ category.name }}
      </md-option>
    </md-autocomplete>
  </md-form-field>
</div>

这是我的TypeScript代码:

constructor(private placeService: PlaceService, private categoryService: CategoryService) {
    this.categoryCtrl = new FormControl();
    this.filteredCategories = this.categoryCtrl.valueChanges
        .startWith('')
        .map(category => category ? this.filterCategories(category) : this.categories.slice());
}

filterCategories(name: string) {
    return this.categories.filter(category => category.name.toLowerCase().indexOf(name.toLowerCase()) === 0);
}

selectCategory(category: any) {
    const index = this.selectedCategories.indexOf(category.option.value);
    if (index === -1) {
        this.selectedCategories.push(category.option.value)
    }
}

我已经检查了Angular Material文档,但我还没有找到一种方法来执行此操作.

谢谢.

Answer 1

我认为你很接近,看起来唯一缺少的部分是重置表单控件值selectCategory.这就是我们在自己的应用程序中完成它的方式,但它实际上是相同的:

/** Reference to the autocomplete trigger. */
@ViewChild(MdAutocompleteTrigger)
private trigger: MdAutocompleteTrigger;

/** Form control for the input. */
searchControl = new FormControl('');

ngAfterViewInit() {
  // Clear the input and emit when a selection is made
  this.trigger.autocomplete.optionSelected
    .map(event => event.option)
    .subscribe(option => {
      // This may or may not be needed, depending on your purposes
      option.deselect();

      // Emit the selection (so parent component can add chip)
      this.selection.emit(option.value);

      // Reset the value of the input
      this.searchControl.setValue('');
    });
}

每当您选择一个值时,所选文本都会有一个简短的"闪烁".为避免这种情况,您可以使用该displayWith属性将选定值显示为空:

<md-autocomplete #auto="mdAutocomplete" [displayWith]="displayNull">
  ...
</md-autocomplete>

/** Display function for selected autocomplete values. */
displayNull(value) {
  return null;
}

Answer 2

这是我的方法

在模板中

...
<md-autocomplete #auto="mdAutocomplete" [displayWith]="displayNull" (optionSelected)="selectHandler($event)">
...

在组件.ts中

public selectHandler(event : MdAutocompleteSelectedEvent) : void
{
    event.option.deselect()
    this.doStuffWith(event.option.value)
}

public displayNull()
{
    return null
}

Answer 3

遇到了这个解决方案，但我不喜欢这个displayNull修复。

我的解决方案看起来与此类似：

组件.html：

  <input matInput [matAutocomplete]="auto" (input)="filter($event.target.value)" #autoInput>
  <mat-autocomplete #auto [displayWith]="displayKey" (optionSelected)="emit($event, autoInput)">
  // ...
  </mat-autocomplete>

组件.ts：

@Output() optionSelected = new EventEmitter<MatAutocompleteSelectedEvent>();

emit(event: MatAutocompleteSelectedEvent, ele: HTMLInputElement) {
  ele.value = '';
  ele.blur();
  this.filter('');
  this.optionSelected.emit(event);
}