// Entity Framework Plus

// Doc: https://entityframework-plus.net/query-future

​

// @nuget: Microsoft.EntityFrameworkCore.SqlServer

// @nuget: Z.EntityFramework.Plus.EFCore

​

using System;

using System.Linq;

using Z.EntityFramework.Plus;

using Microsoft.EntityFrameworkCore;

using Microsoft.Data.SqlClient;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        using (var context = new EntityContext())

        {

            context.Database.EnsureCreated();

        }

        GenerateData();

​

        using (var context = new EntityContext())

        {

            var futurePost = context.Posts.OrderBy(x => x.CreatedDate).Take(10).Future();

            var futurePostCount = context.Posts.DeferredCount().FutureValue();

​

            // ONE database round trip is required

            var post = futurePost.ToList();

            var postCount = futurePostCount.Value;

            Console.WriteLine("Future Post Count: {0}", postCount); 

        }

    }

    public static void GenerateData()

    {

        using (var context = new EntityContext())

        {           

            context.Posts.Add(new Post() {Title = "Post_A", CreatedDate = DateTime.Now.AddDays(-35), ViewCount = 12});

            context.Posts.Add(new Post() {Title = "Post_B", CreatedDate = DateTime.Now.AddDays(-17), ViewCount = 41});

            context.Posts.Add(new Post() {Title = "Post_C", CreatedDate = DateTime.Now.AddDays(-5), ViewCount = 24});

            context.SaveChanges();

        }

    }

​

    public class EntityContext : DbContext

    {

        public EntityContext() 

        {

        }

​

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

        {

            optionsBuilder.UseSqlServer(new SqlConnection(FiddleHelper.GetConnectionStringSqlServer()));

​

            base.OnConfiguring(optionsBuilder);

        }

        public DbSet<Post> Posts { get; set; }

    }

    public class Post

    {

        public int PostId { get; set; }

        public string Title { get; set; }

        public DateTime CreatedDate { get; set; }

        public int ViewCount { get; set; }

    }

}