I am trying to open an ngx Modal window after an http call made from an angular application.

Here is the code of app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { ReactiveFormsModule } from '@angular/forms';
import { AppComponent } from './app.component';
import { HttpClientModule } from '@angular/common/http';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
import { ModalModule } from 'ngx-bootstrap/modal';
@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    HttpClientModule,
    ReactiveFormsModule,
    BrowserAnimationsModule,
    ModalModule.forRoot(),
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

Here is the code of the component in which the http call is made

import { Component, TemplateRef, ViewChild } from '@angular/core';
import { HttpClient, HttpHeaders } from '@angular/common/http';
import { FormControl, FormGroup, Validators } from '@angular/forms';
import { Tour } from './Models/Tour/tour.model';
import { BsModalService, BsModalRef } from 'ngx-bootstrap/modal';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  title = 'AnguLearn';
  public fGroup: FormGroup;
  public Tours : Tour[] = [];
  public Empty = false;
  @ViewChild('template', {static: true}) modalr? : TemplateRef<any>;
  modalRef?: BsModalRef;
  constructor(private modalService: BsModalService){
      
  }
  
  public getDatas(){
    
    const httpOptions = {
      headers: new HttpHeaders({
         'Content-Type': 'application/json; charset=utf-8'
      })
   };

  this.http.post<[Tour]>("https://localhost:44387/api/tours", filter_details, httpOptions).subscribe(
      (response)=>{
        this.Tours = response;
        this.Empty = response.length <= 0;
        this.openModal(this.modalr);//I want to open a modal box here
      }, errors=>{ console.log(errors)});
  }

  openModal(template: TemplateRef<any>) {
    this.modalRef = this.modalService.show(template);
  }
}

It did not work, and it did not compile. I always get the following error on the line with this.openModal(this.modalr); :

Argument of type 'TemplateRef | undefined' is not assignable to parameter of type 'TemplateRef'. Type 'undefined' is not assignable to type 'TemplateRef'.

Any idea?