Unexpected Behavior When Using Entity Framework Core with PostgreSQL - Null Reference Exception on Lazy Loading
I'm working through a tutorial and After trying multiple solutions online, I still can't figure this out. I'm working on a project and hit a roadblock. I'm stuck on something that should probably be simple. I am experiencing a frustrating issue when using Entity Framework Core (version 5.0) with PostgreSQL. I have set up lazy loading for my entities, but I am getting a `NullReferenceException` when I try to access a navigation property after querying the database. Below is a simplified version of my setup: ```csharp public class Blog { public int BlogId { get; set; } public string Url { get; set; } public virtual ICollection<Post> Posts { get; set; } } public class Post { public int PostId { get; set; } public string Title { get; set; } public int BlogId { get; set; } public virtual Blog Blog { get; set; } } public class BloggingContext : DbContext { public DbSet<Blog> Blogs { get; set; } public DbSet<Post> Posts { get; set; } protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<Blog>().Navigation(b => b.Posts).Load(); // Explicit Loading } } ``` In my service layer, when I try to access the `Posts` property of a `Blog` object: ```csharp using (var context = new BloggingContext()) { var blog = context.Blogs.FirstOrDefault(b => b.BlogId == 1); var posts = blog.Posts.ToList(); // NullReferenceException here } ``` The `blog` object is not null, but when I try to access `blog.Posts`, I get a `NullReferenceException`. I double-checked that the `BlogId` exists in the database, and I am sure that there are posts related to that blog. I've tried turning off lazy loading by setting the `LazyLoadingEnabled` property to false, and I also attempted to explicitly load the `Posts` using `.Include(b => b.Posts)`, but I still encounter the same error. ```csharp var blog = context.Blogs.Include(b => b.Posts).FirstOrDefault(b => b.BlogId == 1); ``` This approach doesn't throw an exception, but `blog.Posts` is still null. I suspect there might be an issue with how the navigation properties are configured or some oversight in my context setup. Can anyone provide insights into what might be causing this issue, or suggest best practices for working with lazy loading in EF Core with PostgreSQL? This is part of a larger application I'm building. Thanks in advance! This is part of a larger API I'm building. Thanks in advance! Any pointers in the right direction? My development environment is Ubuntu 20.04.