// Entity Framework Classic

// Doc: https://entityframework-classic.net/linq-dynamic

​

// @nuget: Z.EntityFramework.Classic

​

using System;

using System.Collections.Generic;

using System.Data.Entity;

using System.Linq;

using System.Linq.Expressions;  

using Z.Expressions;

public class Program

{

    public static void Main()

    {

        GenerateData();

        using (var context = new EntityContext())

        {

            FiddleHelper.WriteTable(context.Invoices.SelectMany(x => "x.InvoiceItems"));

        }       

    }

    public static void GenerateData()

    {

        List<Invoice> list =  new List<Invoice>() {

        new Invoice() { Description = "Invoice_A", InvoiceItems = new List<InvoiceItem>() { new InvoiceItem() { Description = "Invoice_A_InvoiceItem_A" } , new InvoiceItem() { Description = "Invoice_A_InvoiceItem_B" }}}, 

        new Invoice() { Description = "Invoice_B", InvoiceItems = new List<InvoiceItem>() { new InvoiceItem() { Description = "Invoice_B_InvoiceItem_A" } , new InvoiceItem() { Description = "Invoice_B_InvoiceItem_B" }}}};

        // BulkInsert: INCLUDE child entities

        using (var context = new EntityContext())

        {

            context.BulkInsert(list, options => options.IncludeGraph = true);

        }

    }

​

    public class EntityContext : DbContext

    {

        public EntityContext() : base(FiddleHelper.GetConnectionStringSqlServer())

        {

​

        }

        public DbSet<Invoice> Invoices { get; set; }

        public DbSet<InvoiceItem> InvoiceItems { get; set; }

    }

    public class Invoice

    {

        public int InvoiceID { get; set; }

        public string Description { get; set; }

        public List<InvoiceItem> InvoiceItems { get; set; }

    }

    public class InvoiceItem

    {

        public int InvoiceItemID { get; set; }

        public string Description { get; set; }

    }

}