Filtering related tables in EF Core 2.0 - asp.net

Question

I'm working at my first project in .Net Core 2.0. It is a simple blog system. I want to add search functionality based on post title and tags.
My entities:
public class Post
{
public int ID { get; set; }
public string Title { get; set; }
public string Description { get; set; }
public string Body { get; set; }
public int CategoryID { get; set; }
public DateTime ReleaseDate { get; set; }
public string ImageName { get; set; }
public Category Category { get; set; }
public ICollection<PostTag> PostTags { get; } = new List<PostTag>();
}
public class PostTag
{
public int PostID { get; set; }
public int TagID { get; set; }
public Post Post { get; set; }
public Tag Tag { get; set; }
}
public class Tag
{
public int TagID { get; set; }
public string Name { get; set; }
public int Counter { get; set; }
public ICollection<PostTag> PostTags { get; } = new List<PostTag>();
public Tag()
{
Counter = 1;
}
So far I have come up with something like that. I joined the Tag table to be able to view all the tags for each post in IndexView.
public async Task<IActionResult> Index(int? page, string searchString)
{
IQueryable<Post> posts = _context.Posts
.OrderByDescending(post => post.ReleaseDate)
.Include(post => post.Category)
.Include(post => post.PostTags)
.ThenInclude(pt => pt.Tag);
//SEARCH
if (!String.IsNullOrEmpty(searchString))
{
posts = posts.Where(post => post.PostTags.Any(pt => pt.Tag.Name.Contains(searchString)) || post.Title.Contains(searchString));
//POPULARITY INCREESE
var tag = _context.Tags.SingleOrDefault(t => t.Name == searchString);
if (tag != null)
{
tag.Counter += 1;
_context.Update(tag);
_context.SaveChanges();
}
}
int pageSize = 4;
return View("Index", await PaginatedList<Post>.CreateAsync(posts.AsNoTracking(), page ?? 1, pageSize));
}
It's wroking but I would like to know if there is a simpler or better way.
And will .Where function work when i dont include related tables?

Answer 1

First of all the answer to your last question: As long as you didn´t send any request to the database, you don´t need Include() for filtering.
If you want to populate a list of entities, and you want to access Navigation-Properties e.g. while iterating over the list, you need to use Include().
If you want to avoid using Include(), you should select the values you need. This will avoid unexpected behaviour with NavigationProperties or something like this too. I would do something like this:
IQueryable<Post> posts = _context.Posts.OrderByDescending(post => post.ReleaseDate);
//SEARCH
if (!String.IsNullOrEmpty(searchString))
{
posts = posts.Where(post => post.PostTags.Any(pt => pt.Tag.Name.Contains(searchString)) || post.Title.Contains(searchString));
//POPULARITY INCREESE
var tag = _context.Tags.SingleOrDefault(t => t.Name == searchString);
if (tag != null)
{
tag.Counter += 1;
_context.Update(tag);
_context.SaveChanges();
}
}
int pageSize = 4;
return View("Index", await PaginatedList<Post>.CreateAsync(posts.AsNoTracking().Select(e=> new YourDisplayObject { DiplayValue = e.DbValue, DisplayNavProp = e.NavProp }, page ?? 1, pageSize));