角度下拉菜单-多选下拉菜单顶部的选定值

Question

我需要将所选的值保留在multiselect的下拉列表的顶部。我将选定值保存在一个数组中（对于每个选定项），将原始选项列表保存在另一个数组中，将索引值和串联的选定值与数组顶部进行了比较。当我选择一个值而不是多个值时，它会起作用

html

<div>
  <ng-multiselect-dropdown  class ="ng-multiselect" [placeholder]="'Users'"
[data]="userList" [(ngModel)]="selectedUsers"  [settings]="multiSelect"
name="user" (onSelect)="onItemSelect($event)" (click)="userSelectedAtTopOnClick()">
  </ng-multiselect-dropdown>
</div>

ts

onItemSelect(user: User) {
  this.userData = user;
}

userSelectedAtTopOnClick(): void {
    this.isUserDropDownWidgetHidden = document.querySelector('.dropdown-list').hasAttribute("hidden");
    if(this.isUserDropDownWidgetHidden ) {
      this.sortUserListAfterEachSelection(this.userData);
    }
}

sortUserListAfterEachSelection(user: User) {
    let arrPartner: Partner[];
    if(origInst) {
      const index = this.userList.findIndex(element => element.partnerId === user.partnerId);
      const item: Partner = this.userList[index];
      if (index > -1) {
        arrPartner = this.userList.splice(index, 1);
        arrPartner = arrPartner.concat(this.userList);
        this.userList = arrPartner;
      }
    }
  }