NullReferenceException When Using Entity Framework Core with Lazy Loading in .NET 7
Hey everyone, I'm running into an issue that's driving me crazy... I am working with a `NullReferenceException` when trying to access related entities in my .NET 7 application using Entity Framework Core with lazy loading enabled. The behavior occurs when I attempt to access a navigation property in a model after retrieving the data from the database. Here's a simplified version of my setup: ```csharp public class Blog { public int BlogId { get; set; } public string Name { 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).UseLazyLoading(); } } ``` After setting up and running the following code, I get the `NullReferenceException`: ```csharp using (var context = new BloggingContext()) { var blog = context.Blogs.FirstOrDefault(b => b.BlogId == 1); var posts = blog.Posts.ToList(); // Exception occurs here } ``` I have checked the database, and there are indeed posts associated with the blog. I also verified that lazy loading is properly configured by ensuring the relevant packages are included, such as `Microsoft.EntityFrameworkCore.Proxies`. I have tried explicitly loading the `Posts` collection using `Include` and that works fine: ```csharp var blogWithPosts = context.Blogs.Include(b => b.Posts).FirstOrDefault(b => b.BlogId == 1); ``` However, I prefer to use lazy loading for cleaner code. Has anyone faced a similar scenario or know what might be causing the lazy loading to unexpected result? I suspect it might be related to how the DbContext is disposed, but I'm not sure. Any insights would be greatly appreciated! Any ideas what could be causing this? This is happening in both development and production on Debian. My team is using C# for this application.