工作单元模式和存储库模式的界面

public interface IUnitOfWork : IDisposable
{
    bool IsActive { get; }

    bool WasCommitted { get; }

    /// <summary>
    /// Commits all changes made on the unit of work.
    /// </summary>
    void Commit();

    bool WasRolledBack { get; }

    /// <summary>
    /// Rolls back all changes made on the unit of work.
    /// </summary>
    void Rollback();

    /// <summary>
    /// Returns an instance of an entity with the specified key that is attached to the unit of work without
    /// loading the entity from a repository.
    /// </summary>
    /// <param name="id"></param>
    /// <returns></returns>
    T Load<T>(int id)
        where T : class;

    void Attach<T>(T entity)
        where T : class, IIdentifiable;

    void Detach<T>(T entity)
        where T : class;

    IRepository<T> GetRepository<T>()
        where T : class;
}

public interface IRepository<T>
    where T : class
{

    IUnitOfWork UnitOfWork { get; }

    void Add(T entity);

    void Remove(T entity);

    /// <summary>
    /// Returns an instance of an entity with the specified key that is attached to the unit of work by loading
    /// the entity from the repository.
    /// </summary>
    /// <param name="id"></param>
    /// <returns></returns>
    T Get(int id);

    IQueryable<T> All();
}

public interface IEntity
{
    GUID Id { get; }
}

public interface IUnitOfWork<TEntity> where TEntity : IEntity, class 
    : IDisposable
{
    void Commit();
    void Discard();
    void Track(TEntity entity);
    void Delete(TEntity entity);
}

public interface IRepository<TEntity> where TEntity : IEntity, class 
    : IDisposable
{
    IUnitOfWork<TEntity> UnitOfWork { get; }

    TEntity CreateNew();
    T FindOne(ISpecification criteria);
    IEnumerable<T> FindMandy(ISpecification criteria);
    IEnumerable<T> FetchAll();
}

public interface ISpecification
{
    // encapsulates everything what is needed for a query 
    // this might be an SQL-statement, LINQ-functor... 

    string CommandText { get; }
    object[] Arguments { get; set; }
    bool IsSatisfiedBy(object candidate);
}