telegram-bot/Core/Data/BotUserValue.cs

using System;
using System.ComponentModel.DataAnnotations;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;

namespace Kruzya.TelegramBot.Core.Data
{
    public class BotUserValue
    {
        [Key]
        public Guid BotUserValueId { get; set; }
        
        public BotUser BotUser { get; set; }
        public string Name { get; set; }
        
        public byte[] Value
        {
            get
            {
                var fmt = new BinaryFormatter();
                using var memStream = new MemoryStream();
                fmt.Serialize(memStream, data);
                
                return memStream.ToArray();
            }
            set
            {
                var fmt = new BinaryFormatter();
                using var memStream = new MemoryStream();
                memStream.Write(value);
                memStream.Position = 0;

                data = fmt.Deserialize(memStream);
            }
        }

        [NonSerialized] public object data;
        
        public T GetValue<T>() => (T) data;
        public void SetValue<T>(T value) => data = value;
    }
}