// 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();

        var context = new EntityContext();

        var oftypeWorker = context.Employees.OfType(typeof(Worker));

        FiddleHelper.WriteTable(oftypeWorker);

        string boss = typeof(Boss).FullName;        

        var oftypeBoss = context.Employees.OfType(boss);

        FiddleHelper.WriteTable(oftypeBoss);

        int numberOfBosses = context.Employees.Count("is(@0)", boss);

        Console.WriteLine("numberOfBosses = {0}", numberOfBosses);

        int useAsToCheckIftheTypeIsABoss = context.Employees.Count("As(@0) != null", boss);

        Console.WriteLine("useAsToCheckIftheTypeIsABoss = {0}", useAsToCheckIftheTypeIsABoss);

        var allWorkers = context.Employees.OfType(typeof(Worker));

        var castToWorkers = allWorkers.Cast(typeof(Worker));

        FiddleHelper.WriteTable(castToWorkers);

    }

    public static void GenerateData()

    {

        var list = new List<BaseEmployee>

        {

            new Worker { Name = "w1", Other = "o1" },

            new Worker { Name = "w2", Other = "02" },

            new Boss { Name = "b", Function = "f" }

        };

        using (var context = new EntityContext())

        {

            context.Employees.AddRange(list);

            context.BulkSaveChanges();

        }

    }

    public class EntityContext : DbContext

    {

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

        {

        }

        public DbSet<BaseEmployee> Employees { get; set; }

    }

    public abstract class BaseEmployee

    {

        public int Id { get; set; }

        public string Name { get; set; }

    }

    public class Boss : BaseEmployee

    {

        public string Function { get; set; }

    }

    public class Worker : BaseEmployee

    {

        public string Other { get; set; }

    }

    public class Order

    {

        public int Id { get; set; }

        public int Amount { get; set; }

        public double Price { get; set; }

    }

    public class Customer

    {

        public int Id { get; set; }

        public string Name { get; set; }

        public string CompanyName { get; set; }

        public string City { get; set; }

        public string Phone { get; set; }

    }   

}