// 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())

        {

            // GET the first active customer and the number of active customers

            var futureFirstCustomer = context.Customers.DeferredFirstOrDefault().FutureValue();

            var futureCustomerCount = context.Customers.DeferredCount().FutureValue();

​

            // TRIGGER all pending queries

            Customer firstCustomer = futureFirstCustomer.Value;

​

            // The future query is already resolved and contains the result

            var count = futureCustomerCount.Value;

            Console.WriteLine("First Customer Name: {0}", firstCustomer.Name);

            Console.WriteLine("Future Customer Count: {0}", count);

        }

    }

    public static void GenerateData()

    {

        using (var context = new EntityContext())

        {

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

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

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

​

            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<Customer> Customers { get; set; }

    }

    public class Customer

    {

        public int CustomerID { get; set; }

        public string Name { get; set; }

        public Boolean IsActive { get; set; }

    }

}