// 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();

​

        SelectMany();

        SelectMany_Dynamic();

        SelectMany_DynamicTyped();

        SelectMany_Dynamic_IntoType();

    }

    private static void SelectMany()

    {

        var context = new EntityContext();

        var result = context.Users.SelectMany("u => u.Roles.Select(r => r.Name)").ToDynamicArray();

        Console.WriteLine("All role-names : {0}", string.Join(", ", result));

    }

    private static void SelectMany_Dynamic()

    {

        var context = new EntityContext();

        var result = context.Users.SelectMany("Roles.SelectMany(Permissions)").Select("Name");

        FiddleHelper.WriteTable(result);

    }

    private static void SelectMany_DynamicTyped()

    {

        var context = new EntityContext();

        var result = context.Users.SelectMany<Permission>("Roles.SelectMany(Permissions)");

        FiddleHelper.WriteTable(result);

    }

    private static void SelectMany_Dynamic_IntoType()

    {

        var context = new EntityContext();

        var result = context.Users.SelectMany(typeof(Permission), "Roles.SelectMany(Permissions)");

        FiddleHelper.WriteTable(result);

    }

    public static void GenerateData()

    {

        var permissionAdmin1 = new Permission { Name = "p-Admin" };

        var permissionAdmin2 = new Permission { Name = "p-User" };

        var permissionManager1 = new Permission {Name = "p-Manager" };

        var adminRole = new Role

        {

            Name = "Admin",

            Permissions = new List<Permission> { permissionAdmin1, permissionAdmin2 }

        };

        var managerRole = new Role

        {

            Name = "Manager",

            Permissions = new List<Permission> { permissionManager1 }

        };

        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.Users.AddRange(users);

            context.BulkSaveChanges();

        }

    }

    public class EntityContext : DbContext

    {

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

        {

        }

        public DbSet<User> Users { 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; }

        public virtual ICollection<Permission> Permissions { get; set; }

    }

    public class Permission

    {

        public int Id { get; set; }

        public string Name { get; set; }

    }

}