public class ItemAddedToTab
{

  public ItemAddedToTab(
    Guid tabId,
    string menuItem,
    double price
  )
  {

    if(tabId == Guid.Empty) throw ArgumentNullException("The tab id must be provided.");
    if(string.IsNullOrEmtpy(menuItem)) throw new ArgumentNullException("The menu item must be provided.");
    if(price < 0) throw new ArgumentException("Price must be greater or equal to 0.")

    TabId = tabId;
    MenuItem = menuItem;
    Price = price;

  }

  public Guid TabId { get; private set; }

  public string MenuItem { get; private set; }

  public double Price { get; private set; }

}