ASP.NET MVC use ViewModels with Services

Question

I'm trying to make a simple Blog-application, but I'm a bit stuck on the architecture of the application.

I'd like to create a details-page with the content of the blog-post and a form for adding comment to the post.

My code looks like the following:

ViewModel

public class PostDetailsViewModel
{
 [ValidateNever]
 public Post Post { get; set; }
 [Required]
 public string Comment { get; set; }
 [Required]
 public string Author { get; set; }
}

Service-layer

public class BlogService {
 public void AddComment(int postId, PostDetailsViewModel model) {
 using(var context = new ApplicationDbContext()) {
 Post post = context.Posts.Include(x => x.Comments).Single(x => x.Id == postId);
 
 Comment comment = new Comment();
 comment.Content = model.Content;
 comment.Author = model.Author;
 comment.TimeStamp = DateTime.Now;
 post.Comments.Add(comment);
 context.SaveChanges();
 }
 }
}

Controller

class BlogController{
 public IActionResult Details(int id)
 {
 PostDetailsViewModel model = service.GetPostDetails(id);
 return View(model);
 }
 [HttpPost]
 [ValidateAntiForgeryToken]
 public IActionResult Details(int id, PostDetailsViewModel model)
 {
 if (ModelState.IsValid)
 {
 service.AddComment(id, model);
 return RedirectToAction("Details", new { id = id });
 }
 return View(model);
 }
}

I already did a lot of research on architectural best-practices, but I can't see the wood for the trees anymore...

Could someone provide me with some best-practices/improvements on my architecture?

Thank you in advance!

• Sam: @GregBurghardt: well, it doesn't really answer my question how to create a viewmodel that contains a) data to show in the view b) properties for model-binding in a form
• Greg Burghardt: I see now. I retracted my duplicate vote.
• Greg Burghardt: Can you edit your question to include information from your last comment? Asking for "best practices" usually results in questions being closed as opinion-based or needing focus. The additional requirement of how to design this specific page for details and data entry might make this a better fit.
• Greg Burghardt: Can you focus your question on the problem you have with your current design? Asking for general feedback or best practices prevents the community from agreeing on a single objective answer.