using Microsoft.EntityFrameworkCore;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

​

public class Program

{

    public static async Task Main()

    {

        var options = new DbContextOptionsBuilder<MyContext>().UseSqlServer(FiddleHelper.GetConnectionStringSqlServerNorthwind()).Options;

        using (var ctx = new MyContext(options))

        {

            var withoutIncludeCondition = await ctx.Customers.Where(x => x.CustomerID == "VINET").Include(x => x.Orders).FirstOrDefaultAsync();

            var withIncludeCondition = await ctx.Customers.Where(x => x.CustomerID == "VINET").Include(x => x.Orders.Where(y => y.ShipVia == 2)).FirstOrDefaultAsync();

            FiddleHelper.WriteTable("WithoutIncludeCondition", withoutIncludeCondition.Orders);

            FiddleHelper.WriteTable("WithIncludeCondition", withIncludeCondition.Orders);

        }

    }

}

​

public class MyContext : DbContext

{

    public MyContext(DbContextOptions<MyContext> options): base(options)

    {

    }

​

    public DbSet<Order> Orders { get; set; }

​

    public DbSet<Customer> Customers { get; set; }

}

​

public class Order

{

    public int OrderID { get; set; }

​

    public string CustomerID { get; set; }

​

    public Customer Customer { get; set; }

​

    public decimal Freight { get; set; }

​

    public int ShipVia { get; set; }

}

​

public class Customer

{

    public string CustomerID { get; set;}

    public string ContactName { get; set; }

    public List<Order> Orders { get; set; } = new List<Order>();

}