mat-autocomplete 搜索适用于模拟数据，从后端服务分配数据时不起作用

如何解决mat-autocomplete 搜索适用于模拟数据，从后端服务分配数据时不起作用

mat-autocomplete 适用于模拟数据。当我将它与实际服务集成时，它不会填充下拉列表。

我的 html 看起来像这样

     <mat-form-field class="example-full-width">
          <input
            matInput
            placeholder="LastName,FirstName"
            aria-label="LastName,FirstName"
            [matAutocomplete]="auto"
            [formControl]="userCtrl"
          />
          <mat-autocomplete #auto="matAutocomplete">
            <mat-option
              (click)="onSelect(user,i)"
              *ngFor="let user of filteredUsers | async; let i = index"
              [value]="user.name"
            >
              <span>{{ user.name }}</span>
              <!-- <small> GUID: {{user.guid}}</small> -->
            </mat-option>
          </mat-autocomplete>
        </mat-form-field>

组件如下

import {Component,Inject,ViewChild,OnInit} from '@angular/core';
import { MAT_DIALOG_DATA} from '@angular/material/dialog';
import { FormControl } from "@angular/forms";
import { Observable } from "rxjs";
import { map,startWith } from "rxjs/operators";
import { UserService } from '../../../shared/services/user/user.service';

  @Component({
    selector: "app-change-user-dialog",templateUrl: "./change-user-dialog.component.html",styleUrls: ["./change-user-dialog.component.scss"]
  })
  
  export class ChangeUserComponent implements OnInit {

  userCtrl: FormControl;
  filteredUsers: any;
  selectedUser = "";

  users = [
    {
      name: "Barrett,David",guid: "1213123"
    },{
      name: "Barrett,Elizabeth",guid: "8437593"
    },guid: "2o934u124"
    }
  ];

  constructor( public dialogRef: MatDialogRef<ChangeUserDialogComponent>,@Inject(MAT_DIALOG_DATA) public data: ChangeUserDialogComponent,private userService: UserService ) {
    this.userCtrl = new FormControl();
    this.filteredUsers = this.userCtrl.valueChanges.pipe(
      startWith(""),map(user => (user.length >= 3 ? this.filterUsers(user) : []))

    );
  }
  
  ngOnInit(): void {
   
    }

     filterUsers(name) {
       this.users.filter((user) => {
       return user.name.toLowerCase().indexOf(name.toLowerCase()) === 0
       });
    }

  }

上面的组件工作正常并显示带有模拟数据的下拉菜单，

现在，我试图从服务中获取响应并将其分配回 this.users，但它不起作用。

以下是我试过的

filterUsers(name: string) {
      var split_str = name.split(",");
      const lastname = split_str[0] ? split_str[0] : "";
      const firstname = split_str[1] ? split_str[1] : "";
      this.userService.getGuidByName(firstname,lastname).subscribe((data) => {
      this.users = data;
      return this.users.filter(
        user => user.name.toLowerCase().indexOf(name.toLowerCase()) === 0
        );
      });   
    }

我的服务如下图

 public getGuidByName(firstname,lastname): Observable<any> {
    return this.httpService.get('file',`/search?firstname=${firstname}&lastname=${lastname}`)
    .pipe(
      catchError(this.httpService.handleError('error'))
    );
  }

服务响应与我使用的模拟数据完全相同。

我错过了什么？任何输入表示赞赏。谢谢。