ddd

 
[Serializable]
public class Match
{
 
   public Player PlayerOne { get; private set; }
   public Player PlayerTwo { get; private set; }
 
 
   internal bool PlayersInCommon(Match match)

 
[Serializable]
public class Match
{
   public Player PlayerOne { get; private set; }
   public Player PlayerTwo { get; private set; }
 
   ...
}

public abstract class EntityBase {
    private object key;
    
    protected EntityBase() : this(null) {
    }
    
    protected EntityBase(object key) {
        this.key = key;
    }
    

namespace Northwind
{
    /// <summary>
    /// A base class for all entities that implements identity equality.
    /// </summary>
    /// <typeparam name="TId">The type of the ID.</typeparam>
    /// <typeparam name="T">The type of the derived class (required for equality)</typeparam>
    public abstract class EntityBase<TId, T> where T : EntityBase<TId, T>
    {
        private TId _id;