// Dynamic LINQ - stef

​

// @nuget: System.Linq.Dynamic.Core

// @nuget: Z.EntityFramework.Classic

​

using System;

using System.Collections.Generic;

using System.Linq;

using System.Data.Entity;

using System.Linq.Dynamic.Core;

public class Program

{   

    public static void Main()

    {

        GenerateData();

        using (var context = new EntityContext())

        {

            var orders = context.Orders.Where("OrderDate >= DateTime(2020, 4, 1)").ToList();

            FiddleHelper.WriteTable(orders);

        }

    }

    public static void GenerateData()

    {

        var list = new List<Customer>

        {

            new Customer

            {

                Name = "Terri Lee Duffy",

                CompanyName = "ABC",

                City = "Paris",

                Phone = "333-444444",

                Orders = new List<Order>()

                {

                    new Order() { OrderDate = DateTime.Today.AddDays(-41) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-38) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-21) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-18) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-10) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-9) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-5) },

                    new Order() { OrderDate = DateTime.Today },

                }

            },

            new Customer

            {

                Name = "Janice Galvin",

                CompanyName = "XYZ",

                City = "London",

                Phone = "333-555555",

                Orders = new List<Order>()

                {

                    new Order() { OrderDate = DateTime.Today.AddDays(-25) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-11) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-7) },

                    new Order() { OrderDate = DateTime.Today }

                }

            },

            new Customer

            {

                Name = "Michael Raheem",

                CompanyName = "DEF",

                City = "New York",

                Phone = "111-555555",

                Orders = new List<Order>()

                {

                    new Order() { OrderDate = DateTime.Today.AddDays(-4) },

                    new Order() { OrderDate = DateTime.Today }

                }

            },

            new Customer

            {

                Name = "Michael Sullivan",

                CompanyName = "ABC",

                City = "Paris",

                Phone = "333-888888",

                Orders = new List<Order>()

                {

                    new Order() { OrderDate = DateTime.Today.AddDays(-35) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-21) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-17) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-11) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-4) },

                    new Order() { OrderDate = DateTime.Today }

                }

            },

            new Customer

            {

                Name = "Rebecca Bradley",

                CompanyName = "KLM",

                City = "Tokyo",

                Phone = "333-666666",

                Orders = new List<Order>()

                {

                    new Order() { OrderDate = DateTime.Today.AddDays(-21) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-18) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-10) },

                    new Order() { OrderDate = DateTime.Today.AddDays(-9) },

                }

            }

        };

​

        using (var context = new EntityContext())

        {

            context.Customers.AddRange(list);

            context.BulkSaveChanges();

        }

    }

    public class EntityContext : DbContext

    {

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

        {

        }

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

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

    }

    public class Customer

    {

        public int CustomerID { get; set; }

        public string Name { get; set; }

        public string CompanyName { get; set; }

        public string City { get; set; }

        public string Phone { get; set; }

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

    }

​

    public class Order

    {

        public int OrderID { get; set; }

        public DateTime OrderDate { get; set; }

    }

}