// Entity Framework Classic

// Doc: https://entityframework-classic.net/query-deferred

​

// @nuget: Z.EntityFramework.Classic

​

using System;

using System.Linq;

using System.Collections.Generic;

using System.Data.Entity;

​

public class Program

{

    public static void Main()

    {

        GenerateData();

​

        using (var context = new EntityContext())

        {           

            // Not do Select

            var futurValue_B = context.Customers.OrderBy(x => x.CustomerID).DeferredFirstOrDefault(x => x.Name.Equals("Customer_B")).FutureValue();

            var futurValue_1 = context.Customers.OrderBy(x => x.CustomerID).DeferredFirstOrDefault().FutureValue();

            // SELECT TOP 1 * FROM Customers Where  Name = 'Customer_B' order by CustomerID

            // SELECT TOP 1 * FROM Customers' order by CustomerID

            FiddleHelper.WriteTable("Customers", new List<Customer>{futurValue_B.Value, futurValue_1.Value});           

        }

    }

    public static void GenerateData()

    {

        using (var context = new EntityContext())

        {

            context.Customers.Add(new Customer() { Name = "Customer_A", Description = "Description" });

            context.Customers.Add(new Customer() { Name = "Customer_B", Description = "Description" });         

            context.Customers.Add(new Customer() { Name = "Customer_C", Description = "Description" });

            context.SaveChanges();  

        }

    }

​

    public class EntityContext : DbContext

    {       

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

        {       

        }

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

    }

    public class Customer

    {

        public int CustomerID { get; set; }

        public string Name { get; set; }

        public string Description { get; set; }

    }

}