using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var nazevTridy = "MyClass";

        Type typ = Type.GetType(nazevTridy);

        var podminka = typ.GetInterfaces().Contains(typeof(IMyInterface));

        var napis = (podminka) ? "Je IMyInterface." : "Není IMyInterface.";

        Console.WriteLine(napis);

    }

}

​

public interface IMyInterface

{

    string ReturnMyString();

}

​

public class MyClass : IMyInterface

{

    public string ReturnMyString() => nameof(MyClass).ToUpperInvariant();

}