using System;

public class Program

{

    public class ItemData

    {

        public string ItemName { get; init; }

    }

​

    public class WeaponData : ItemData { }

​

    public class Item

    {

        public ItemData Data { get; init; }

​

        public Item(ItemData data)

        {

            Data = data;

        }

    }

​

    public class WeaponItem : Item  

    {

        public WeaponItem(WeaponData data) : base(data) { }

​

        public override string ToString() => Data.ItemName;

    }

​

    public static T CreateNewItem<T, TD>(TD data) 

        where T : Item 

            where TD : ItemData

            {

                return (T)Activator.CreateInstance(typeof(T), data);

            }

​

    static void Main(string[] args)

    {

        var bestWeaponEver = new WeaponData() { ItemName = "Dragon Slayer" };

        var amazingWeaponItem= CreateNewItem<WeaponItem, WeaponData>(bestWeaponEver);

        Console.WriteLine(amazingWeaponItem);

    }

}