Unable to add SharePoint list item with attachment from Angular to ASP.NET Core Web API using NgModel

i use example of this link, How to Upload File from Angular to ASP.NET Core Web API. i think must be like this :

html

<form (ngSubmit)="onSubmit()">
    <div>
        <label for="Name">
            Blog Name
        </label>
        <input type="text" name="Name" [(ngModel)]="Name">
    </div>

    <div>
        <label for="TileImage">
            Tile Image
        </label>
        <input type="file" name="TileImage" [(ngModel)]="TileImage">
    </div>

    <button type="submit">Create Blog</button>

</form>

typescript

import { Component, OnInit } from '@angular/core';
import { FormControl } from '@angular/forms';
import { BlogService } from '../blog-services/blog.service';

@Component({
  selector: 'app-new-blog',
  templateUrl: './new-blog.component.html',
  styleUrls: ['./new-blog.component.css']
})
export class NewBlogComponent implements OnInit {
  public Name = '';
  public TileImage= '';
  constructor(private blogService: BlogService) { }

  ngOnInit() {}

  onSubmit() {
    this.blogService.postBlog({Name:this.Name,TileImage:this.TileImage});
    this.Name='';
    this.TileImage='';
  }

}