Ef base entity

entity.cs

public abstract class Entity
{
    protected Entity()
    {
        Created = SystemTime.InternalNow();
        Updated = SystemTime.InternalNow();
    }

    [Key]
    public long Id { get; set; }

    [HiddenInput(DisplayValue = false)]
    public DateTime Created { get; set; }

    [HiddenInput(DisplayValue = false)]
    public DateTime Updated { get; set; }

    public override bool Equals(object obj)
    {
        var other = obj as Entity;

        if (other == null)
            return false;

        if (ReferenceEquals(this, other))
            return true;

        bool typesMatch = GetUnproxiedType().Equals(other.GetUnproxiedType());

        bool idsMatch = PersistentAndSame(other);

        return typesMatch && idsMatch;
    }

    public override int GetHashCode()
    {
        // ReSharper disable BaseObjectGetHashCodeCallInGetHashCode
        // http://msdn.microsoft.com/en-us/library/system.object.gethashcode(v=VS.110).aspx
        if (IsTransient()) return base.GetHashCode();
        // ReSharper restore BaseObjectGetHashCodeCallInGetHashCode
        unchecked
        {
            return (GetUnproxiedType().GetHashCode()*31) ^ Id.GetHashCode();
        }
    }

    public static bool operator ==(Entity left, Entity right)
    {
        return Equals(left, right);
    }

    public static bool operator !=(Entity left, Entity right)
    {
        return !Equals(left, right);
    }

    bool PersistentAndSame(Entity compareTo)
    {
        return (!Id.Equals(default(long))) &&
                (!compareTo.Id.Equals(default(long))) && Id.Equals(compareTo.Id);
    }

    bool IsTransient()
    {
        return Id == default(long);
    }

    public Type GetUnproxiedType()
    {
        return ObjectContext.GetObjectType(GetType());
    }

    public override string ToString()
    {
        return string.Format("{0} [{1}]", GetUnproxiedType().Name, Id);
    }
}

might want to implement stronger gethashcode.. that's sorta funky.. the hash code should be deterministic across states throughout the object lifetime - this dude will mess up your hashtable if you persist him while he's in there.