如何为素材选择添加backgroundClass？

Question

<mat-select formControlName="country" panelClass="CountySelect" backdropClass="full-width"></mat-select>

想要将backdropClass添加到特定的垫上，选择cdk-overlay-pane。我们该怎么做。文档中没有用于垫选择的名为backdropClass的输入。能做到吗？或通过其他方式实现这一目标？

Answer 1

@Directive({
  selector: '[appBackdropClass]'
})
export class PanelClassDirective implements DoCheck {
  @Input('appBackdropClass') panelClass: string;

  constructor(private _host: MatSelect) {
  }

  ngDoCheck(): void {
    if (this._host.overlayDir) {
      this._host.overlayDir.hasBackdrop = true;
      this._host.overlayDir.backdropClass = this.panelClass;
    }
  }
}

<mat-form-field>
  <mat-select appBackdropClass="test">
...