UnitOfWork

IUnitOfWork.cs

public interface IUnitOfWork
{

    IRepository<TEntity, TKey> GetRepository<TEntity, TKey>(Type repository = null) where TEntity : class, IEntity<TKey>, new() where TKey : IEquatable<TKey>;

    void Save();

    Task SaveAsync();

    void Dispose();
}

UnitOfWork.cs

public class UnitOfWork : IUnitOfWork
{
    private readonly DbContext _context;
    
    private readonly Dictionary<Type, object> _repositories = new Dictionary<Type, object>();

    public UnitOfWork(DbContext dbContext)
    {
        _context = dbContext;
    }

    public void Dispose()
    {
        throw new NotImplementedException();
    }

    public IRepository<TEntity, TKey> GetRepository<TEntity, TKey>(Type repository = null) where TEntity : class, IEntity<TKey>, new() where TKey : IEquatable<TKey>
    {
        if (_repositories.Keys.Contains(typeof(TEntity)))
            return _repositories[typeof(TEntity)] as IRepository<TEntity, TKey>;

        IRepository<TEntity, TKey> repo = null;
        if (repository != null)
            repo = (IRepository<TEntity, TKey>)Activator.CreateInstance(repository, new object[] { _context });
        else
            repo = new GenericRepository<TEntity, TKey>(_context);

        _repositories.Add(typeof(TEntity), repo);

        return repo;
    }

    public void Save()
    {
         _context.SaveChanges();
    }

    public async Task SaveAsync()
    {
        await _context.SaveChangesAsync();
    }
}