C# how detect is some some type is some type

Question

I have some data (is a inherited entity and some realize some interface)
then i have filter it

var needTypes = new List<Type>();
needTypes.Add(typeof( Dlinnomer ));//Some class
needTypes.Add(typeof( IBarometr ));//Some interface

data = data.Where(d => needTypes.Any(s => d is s));

Answer 1

the is operator only works at compile time, you must use a runtime compare. also GetType() return the runtime type, not inherited types or interfaces. so you need to use the Type method .IsAssignableFrom which is the runtime version of the is operator.

var list = data.Where(d => needTypes.Any(s => s.IsAssignableFrom(d.GetType()))).ToList();

Answer 2

By Interface

using System;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            object[] items = { new Person(), new Human() };

            foreach (var item in items)
            {
                if (item is IBase)
                {
                    Console.WriteLine(item.GetType());
                }
            }

            Console.ReadLine();
        }
    }

    public interface IBase
    {
        public int Id { get;  }

    }

    public class Person : IBase
    {
        public int Identifier { get; set; }
        public int Id => Identifier;
    }

    public class Human
    {
        public int Identifier { get; set; }
    }
}

C#9 or higher

class Program
{
    static void Main(string[] args)
    {
        object[] items = { new Person() {Identifier = 3}, new Human() };

        foreach (var item in items)
        {

            if (item as IBase is { } casted)
            {
                Console.WriteLine(casted.Id);
            }

        }

        Console.ReadLine();
    }
}

And for types

static class Extensions
{
    public static bool Implements<I>(this Type source) where I : class 
        => typeof(I).IsAssignableFrom(source);
}

Usage

static void Main(string[] args)
{
    IEnumerable<Type> result = TypesList().Where(type => type.Implements<IBase>());
}

private static object[] TypesArray()
{
    object[] items = { new Person() { Identifier = 3 }, new Human() { Identifier = 2 } };
    return items;
}