How do you construct an Entity class to fetch another Entity from repository?

Question

This is a C# Question, using .NET framework built on Asp.NET Boilerplate. Again, to re-emphasis the question being asked is "HOW...", so if an answer that was provided was a url link or a descriptive explanation on how something was supposed to be done, i would very much appreciate it. (Dont answer questions on how to tie shoelace by showing a picture of a tied shoe, nor do you answer "how to fish" by showing a recording of someone fishing...)

Since the question is pretty basic (i don't need to rephrase/repeat the header again), i'll give an example.

If i have a Forum service, and i create a class to load a Thread. Inside that thread class should be some sort of collection, array, list, or even a dbset of Post that is pulled on construct.

[Table("Thread", Schema = "dbo")]
public class ThreadModel
{
    [Key]
    public long Id { get; set; }

    public string Title { get; set; }

    //Idea 1
    //Value should automatically be pulled and cached the moment class connects to database
    public Post[] Posts { get; set; }

    //Idea 2
    //Post has a constructor to return all post that matches a thread id. While new tag keeps the return value constantly refreshed.
    public Post[] Posts { get { return new Post(this.Id) } }

    //Idea 3
    //Not sure how collection is supposed to work. Does it automatically just pull or will i need to make a method to request?
    public virtual ICollection<Post> Posts { get; set; }

    //Example constructor
    //When connected to database key-value pairs that match database labels will automatically get stored in class
    protected ThreadModel()
    {
        //Idea 1-A
        //Should be a value of null or empty if database yields no results
        Posts = new Post(); 
    }

    public ThreadModel(int threadid) : this()
    {
        //Idea 1-A
        Id = threadid;
        //new Post => returns all posts in db
        //Posts default value is all post in db
        Posts = Posts.Select(post => post.threadid == this.id)

        //Idea 3-A
        Posts = Posts.Get(post => post.threadid == this.id)

        //Idea 4
        Posts = new Posts().GetThread(threadid);
    }
}

Side questions

If all entities are created by inheriting Entity then at what point am i exposed to EntityFramework and DbContext?

I love this example here, submitted by a user as they attempt to connect ABP to their database. But their example doesn't show parent/child resources. I'm unable to find the guide they used to create that, and how it relates back to using ABP to fetch EntityFramework's DbContext example

How does this work? I'm unable to find instructions or explanation for this? (What am i to enter into google to get answers on these mechanics?)

[Table("AbpItems")]
public class Item : Entity
{
    [ForeignKey("PostId")]
    public Post Post { get; set; }
    public int PostId { get; set; }
}

How does this integrate into/with abp's EntityFramework?

Where am i supposed to be creating my Database Table/Class? The project follows the Core.csproj, Application.csproj, and EntityFramework.csproj assembly layout. But it seems like every example is creating the classes at different stages or locations of the solution.

Answer 1

use GetAllIncluding. See https://github.com/aspnetboilerplate/aspnetboilerplate/issues/2617

Here's a complete solution ;

namespace EbicogluSoftware.Forum.Threads
{
    [Table("Threads")]
    public class Thread : FullAuditedEntity
    {
        [Required]
        [StringLength(500)]
        public virtual string Title { get; set; }

        [Required]
        [StringLength(2000)]
        public virtual string Text { get; set; }

        public virtual List<Post> Posts { get; set; }

        public Thread()
        {
            Posts = new List<Post>();
        }
    }

    [Table("Posts")]
    public class Post : FullAuditedEntity
    {
        [Required]
        [StringLength(2000)]
        public virtual string Text { get; set; }
    }

    public class ThreadDto
    {
        public string Title { get; set; }

        public string Text { get; set; }

        public List<PostDto> Posts { get; set; }

        public ThreadDto()
        {
            Posts = new List<PostDto>();
        }
    }

    public class PostDto
    {
        public string Text { get; set; }
    }

    public class ThreadAppService : IApplicationService
    {
        private readonly IRepository<Thread> _threadRepository;

        public ThreadAppService(IRepository<Thread> threadRepository)
        {
            _threadRepository = threadRepository;
        }

        public async Task<List<TenantListDto>> GetThreads()
        {
            var threads = await _threadRepository.GetAllIncluding(x => x.Posts).ToListAsync();
            return threads.MapTo<List<TenantListDto>>();
        }
    }
}

Where am i supposed to be creating my Database Table/Class?

You can create them in YourProject.Core.proj