using System;

using System.Collections.Generic;

using System.ComponentModel.DataAnnotations;

using System.Linq;

​

var list = new List<object> { new ClientTypeA(), new ClientTypeB(), new ClientTypeC() };

​

var mapped = list.Select(ct => ct switch 

                         {

                                ClientTypeA a => Map<ClientTypeA, DtoA>(a) as Dto,

                                ClientTypeB b => Map<ClientTypeB, DtoB>(b) as Dto,

                                ClientTypeC c => Map<ClientTypeC, DtoC>(c) as Dto,

                                _ => throw new Exception(),

                         });

​

foreach (var value in mapped)

{

    Console.WriteLine(value.GetType());

}

​

TOut Map<TIn, TOut>(TIn input) where TOut : new() => new();

​

class ClientTypeA

{

    public Guid Id {get; set;}

    public string Name {get; set;}

}

​

class ClientTypeB

{

    public Guid Id {get; set;}

    public string Name {get; set;}

}

​

class ClientTypeC

{

    public Guid Id {get; set;}

    public string Name {get; set;}

    public int Value {get; set;}

}

​

abstract class Dto

{

    public Guid Id {get; set;}

    public string Name {get; set;}

}

​

class DtoA : Dto

{

​

}

​

class DtoB : Dto

{

​

}

​

class DtoC : Dto

{

    public int Value {get; set;}

}

​