// 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 defaultIfEmpty = context.Customers.Where("Name == \"not-found\"").DefaultIfEmpty();

        FiddleHelper.Dump(defaultIfEmpty);

        var users = context.Users.Select("Roles.Where(r => r.Name == \"Admin\").DefaultIfEmpty().FirstOrDefault()");

        foreach (dynamic user in users)

        {

            FiddleHelper.Dump(user);

        }

    }

    public static void GenerateData()

    {

        var customers = new List<Customer>

        {

            new Customer

            {

                Name = "Terri Lee Duffy",

                CompanyName = "ABC",

                City = "Paris",

                Phone = "333-444444"

            },

            new Customer

            {

                Name = "Alfred",

                CompanyName = "KLM",

                City = "London"

            }

        };

        var adminRole = new Role

        {

            Name = "Admin"

        };

        var managerRole = new Role

        {

            Name = "Manager"

        };

        var users = new List<User>

        {

            new User { Name = "Jack", Roles = new List<Role> { managerRole } },

            new User { Name = "Mike", Roles = new List<Role> { managerRole, adminRole } }

        };

​

        using (var context = new EntityContext())

        {

            context.Customers.AddRange(customers);

            context.Users.AddRange(users);

            context.BulkSaveChanges();

        }

    }

    public class EntityContext : DbContext

    {

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

        {

        }

        public DbSet<User> Users { get; set; }

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

        public DbSet<Location> Locations { 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 Location Location { get; set; }

    }

    public class Location

    {

        public int LocationID { get; set; }

        public string Name { get; set; }

    }

    public class User

    {

        public int Id { get; set; }

        public string Name { get; set; }

        public ICollection<Role> Roles { get; set; }

    }

    public class Role

    {

        public int Id { get; set; }

        public string Name { get; set; }

    }

}