ABP AppService for hierarchical data - hierarchical-data

Question

I need an AppService to load a treeview with a recursive collection of entities like these:
===Products===
Id
Description
Price
Products[] ====> Id
Description
Price
Products[]
====> Id
Description
Price
Products[] ====> Id
Description
Price
Products[]
Is there a ready-made class to derive from? If not, could you suggest what class to derive or what interface to implement, and how to proceed, please?
PS: Possibly with full CRUD operations, but the most important is understand how to load the data.

Answer 1

_productRepository
.GetAllIncluding(x=>x.Products)
.Where(p => p.Id == 1); // or whatever condition
.ToList()
this will give you the list of products and child products of the product with Id 1.

Answer 2

You can use the Include method to specify related data to be included in query results.
Please refer Loading Related Data.
You can refer the below sample.
using Microsoft.EntityFrameworkCore;
using System.Linq;
namespace EFQuerying.RelatedData
{
public class Sample
{
public static void Run()
{
#region SingleInclude
using (var context = new BloggingContext())
{
var blogs = context.Blogs
.Include(blog => blog.Posts)
.ToList();
}
#endregion
#region IgnoredInclude
using (var context = new BloggingContext())
{
var blogs = context.Blogs
.Include(blog => blog.Posts)
.Select(blog => new
{
Id = blog.BlogId,
Url = blog.Url
})
.ToList();
}
#endregion
#region MultipleIncludes
using (var context = new BloggingContext())
{
var blogs = context.Blogs
.Include(blog => blog.Posts)
.Include(blog => blog.Owner)
.ToList();
}
#endregion
#region SingleThenInclude
using (var context = new BloggingContext())
{
var blogs = context.Blogs
.Include(blog => blog.Posts)
.ThenInclude(post => post.Author)
.ToList();
}
#endregion
#region MultipleThenIncludes
using (var context = new BloggingContext())
{
var blogs = context.Blogs
.Include(blog => blog.Posts)
.ThenInclude(post => post.Author)
.ThenInclude(author => author.Photo)
.ToList();
}
#endregion
#region MultipleLeafIncludes
using (var context = new BloggingContext())
{
var blogs = context.Blogs
.Include(blog => blog.Posts)
.ThenInclude(post => post.Author)
.Include(blog => blog.Posts)
.ThenInclude(post => post.Tags)
.ToList();
}
#endregion
#region IncludeTree
using (var context = new BloggingContext())
{
var blogs = context.Blogs
.Include(blog => blog.Posts)
.ThenInclude(post => post.Author)
.ThenInclude(author => author.Photo)
.Include(blog => blog.Owner)
.ThenInclude(owner => owner.Photo)
.ToList();
}
#endregion
#region Eager
using (var context = new BloggingContext())
{
var blog = context.Blogs
.Single(b => b.BlogId == 1);
context.Entry(blog)
.Collection(b => b.Posts)
.Load();
context.Entry(blog)
.Reference(b => b.Owner)
.Load();
}
#endregion
#region NavQueryAggregate
using (var context = new BloggingContext())
{
var blog = context.Blogs
.Single(b => b.BlogId == 1);
var postCount = context.Entry(blog)
.Collection(b => b.Posts)
.Query()
.Count();
}
#endregion
#region NavQueryFiltered
using (var context = new BloggingContext())
{
var blog = context.Blogs
.Single(b => b.BlogId == 1);
var goodPosts = context.Entry(blog)
.Collection(b => b.Posts)
.Query()
.Where(p => p.Rating > 3)
.ToList();
}
#endregion
}
}
}