更新时间:2023-02-13 11:06:13
实体的唯一特性是,它具有长寿命和(半)永久性标识。您可以封装,并表示,通过实施 IEquatable< T>
。下面是做这件事:
The only characteristic of an Entity is that it has a long-lived and (semi-)permanent identity. You can encapsulate and express that by implementing IEquatable<T>
. Here's one way to do it:
public abstract class Entity<TId> : IEquatable<Entity<TId>>
{
private readonly TId id;
protected Entity(TId id)
{
if (object.Equals(id, default(TId)))
{
throw new ArgumentException("The ID cannot be the default value.", "id");
}
this.id = id;
}
public TId Id
{
get { return this.id; }
}
public override bool Equals(object obj)
{
var entity = obj as Entity<TId>;
if (entity != null)
{
return this.Equals(entity);
}
return base.Equals(obj);
}
public override int GetHashCode()
{
return this.Id.GetHashCode();
}
#region IEquatable<Entity> Members
public bool Equals(Entity<TId> other)
{
if (other == null)
{
return false;
}
return this.Id.Equals(other.Id);
}
#endregion
}