using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        List<MachineStatus> machines = new List<MachineStatus>

            {

                new MachineStatus { MachineName = "Machine1", Department = "Department1", LocationName = "Loc1", 

                    Devices = new List<DeviceStatus> 

                {

                    new DeviceStatus { DeviceName = "Device A", IpAddress = "123", DeviceType = "Foo", Status = ConnectionStatus.Connected },

                    new DeviceStatus { DeviceName = "Device B", IpAddress = "345", DeviceType = "Bar", Status = ConnectionStatus.Disconnected },

                    new DeviceStatus { DeviceName = "Device C", IpAddress = "257", DeviceType = "Foo", Status = ConnectionStatus.Disconnected }

                } },

                new MachineStatus { MachineName = "Machine2", Department = "Department2", LocationName = "Loc3", Devices = new List<DeviceStatus> 

                {

                    new DeviceStatus { DeviceName = "Device C", IpAddress = "764", DeviceType = "Foo", Status = ConnectionStatus.Connected },

                    new DeviceStatus { DeviceName = "Device D", IpAddress = "904", DeviceType = "Zed", Status = ConnectionStatus.Connected }

                } }

            };

​

​

            var result = machines.SelectMany(x => x.Devices, (machineObj, devices) => new { machineObj, devices })

                                 .GroupBy(x => new { x.devices.DeviceType, x.machineObj.Department, x.machineObj.LocationName })

                                 .Select(x => new

                                     {

                                         DeviceType = x.Key.DeviceType,

                                         Department = x.Key.Department,

                                         Location = x.Key.LocationName,

                                         machines = x

                                     });

​

            foreach (var item in result)

            {

                Console.WriteLine("Device Type: {0}", item.DeviceType);

                Console.WriteLine("Department : {0}", item.Department);

                Console.WriteLine("Location: {0}", item.Location);

                Console.WriteLine();

                foreach (var machine in item.machines)

                {

                    Console.WriteLine("Machine : {0}, DeviceName : {1}", machine.machineObj.MachineName, machine.devices.DeviceName);

                }

                Console.WriteLine("------------------------------------------");

            }

    }

}

​

 public class MachineStatus

    {

        public string MachineName { get; set; }

        public string Department { get; set; }

        public string LocationName { get; set; }

        public IEnumerable<DeviceStatus> Devices { get; set; }

    }

​

    public class DeviceStatus

    {

        public string DeviceName { get; set; }

        public string DeviceType { get; set; }

        public string IpAddress { get; set; }

        public ConnectionStatus Status { get; set; }

    }

​

    public enum ConnectionStatus

    {

        Connected,

        Disconnected

    }