Many-to-Many Relation only includes one Entity [duplicate] - .net-core

Question

This question already has an answer here:
Many to many relationship mapping in EF Core
(1 answer)
Closed 3 years ago.
Dotnet Core 2.2, EntityFrameworkCore 2.2.3
In a Many-to-Many relation between the entities "Post" and "Category" the linked Entity "PostCategory" returns the "Post" object but for the "Category" object only the Id and not the object itself.
Migrations and database update works fine and all three tables are created.
For the relation itself I tried it with EF "auto magic" and explicit definition of the relation in OnModelCreating in the ApplicationDbContext.
Models
Post-Model
public class Post
{
public int Id { get; set; }
public string Slug { get; set; }
public string Title { get; set; }
public string Abstract { get; set; }
public string Content { get; set; }
public string Author { get; set; }
public DateTime Created { get; set; }
public ICollection<PostCategory> PostCategories { get; set; }
}
Category-Model
public class Category
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public ICollection<PostCategory> PostCategories { get; set; }
}
PostCategory Model
public class PostCategory
{
public int PostId { get; set; }
public Post Post { get; set; }
public int CategoryId { get; set; }
public Category Category { get; set; }
}
DbSets in ApplicationDbContext
public DbSet<Post> BlogPosts { get; set; }
public DbSet<Category> BlogCategories { get; set; }
public DbSet<PostCategory> PostCategories { get; set; }
Get all Posts from Service
public IEnumerable<Post> GetAll()
{
var posts = _context.BlogPosts
.Include(x => x.PostCategories);
return posts;
}
Calling service from Controller
public IActionResult Index()
{
var blogPosts2 = _blogService.GetAll();
...
}
The result is seen in the screenshot.
In ApplicationDbContext I tried two versions:
Version 1:
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
builder.Entity<PostCategory>()
.HasKey(x => new { x.PostId, x.CategoryId });
}
public DbSet<Post> BlogPosts { get; set; }
public DbSet<Category> BlogCategories { get; set; }
public DbSet<PostCategory> PostCategories { get; set; }
Version 2:
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
builder.Entity<PostCategory>()
.HasKey(x => new { x.PostId, x.CategoryId });
builder.Entity<PostCategory>()
.HasOne(pt => pt.Post)
.WithMany(p => p.PostCategories)
.HasForeignKey(pt => pt.PostId);
builder.Entity<PostCategory>()
.HasOne(pt => pt.Category)
.WithMany(t => t.PostCategories)
.HasForeignKey(pt => pt.CategoryId); ;
}
public DbSet<Post> BlogPosts { get; set; }
public DbSet<Category> BlogCategories { get; set; }
public DbSet<PostCategory> PostCategories { get; set; }
Both version migrate and update with no errors and the same result.
I'm grateful for any help.
Best regards
Edit:
I tried the "ThenInclude" before but obviously my Visual Studio auto completion has a problem:
If I ignore the auto completion, then it works, thank you!

Answer 1

To eager load related data in multiple level, you have to use .ThenInclude as follows:
public IEnumerable<Post> GetAll()
{
var posts = _context.BlogPosts
.Include(x => x.PostCategories)
.ThenInclude(pc => pc.Category);
return posts;
}
Here is the more details: Loading Related Data: Including multiple levels