c# - 将 SQliteAsyncConnection 与 UnitOfWork 和存储库模式结合使用

Question

我需要为 Windows 8 应用程序实现完全异步架构，我在数据层中使用 SQLite For winRT 和 SQLite.Net。

到目前为止我做了什么:

DAL

上下文:

public interface IContext
    {
        Task InitializeDatabase();
        SQLiteAsyncConnection GetAsyncConnection();
    }

public class SQLiteAsyncContext : IContext
    {
        private SQLiteAsyncConnection _context;
        private String  _dBPath;

        public SQLiteAsyncContext()
        {
            this._dBPath = Path.Combine(
                Windows.Storage.ApplicationData.Current.LocalFolder.Path, "DBName");
            this._context = new SQLiteAsyncConnection(_dBPath);
        }

        public async Task InitializeDatabase()
        {
            await _context.CreateTableAsync<User>();
        }

        public SQLiteAsyncConnection GetAsyncConnection()
        {
            return _context;
        }
    }

通用存储库:

    public interface IAsyncRepository<T> where T : class
        {
            Task<int> AddAsync(T entity);
            Task<int> UpdateAsync(T entity);
            Task<int> RemoveAsync(T entity);
            Task<IList<T>> GetAllAsync();
            Task<IList<T>> GetBy(System.Linq.Expressions.Expression<Func<T, bool>> predicate);
            Task SaveChanges();

        }

    public class AsyncRepository<T> : IAsyncRepository<T> where T : class, new()
        {
            private SQLiteAsyncConnection _context;

            public AsyncRepository(IContext _context)
            {
                this._context = _context.GetAsyncConnection();
            }

            public async Task<int> AddAsync(T entity)
            {
                return await _context.InsertAsync(entity);
            }

            public async Task<int> UpdateAsync(T entity)
            {
                return await _context.UpdateAsync(entity);
            }

            public async Task<int> RemoveAsync(T entity)
            {
                return await _context.DeleteAsync(entity);
            }

            public async Task<IList<T>> GetAllAsync()
            {
                return await _context.Table<T>().ToListAsync();
            }

            public async Task<IList<T>> GetBy(System.Linq.Expressions.Expression<Func<T, bool>> predicate)
            {
                return await _context.Table<T>().Where(predicate).ToListAsync();
            }
            public Task SaveChanges()
            {
            throw new NotImplementedException();
            }
        }

BL

    public interface IAsyncServices<T> where T : class
    {
        Task<int> AddAsync(T entity);
        Task<int> UpdateAsync(T entity);
        Task<int> RemoveAsync(T entity);
        Task<IList<T>> GetAllAsync();
        Task<IList<T>> GetBy(System.Linq.Expressions.Expression<Func<T, bool>> predicate);
    }

public class AsyncUserService : IAsyncServices<User>
    {
        private readonly IAsyncRepository<User> _asyncUserRepository;

        public AsyncUserService(IAsyncRepository<User> _asyncUserRepository)
        {
            this._asyncUserRepository = _asyncUserRepository;
        }

        public async Task<int> AddAsync(User entity)
        {
            return await _asyncUserRepository.AddAsync(entity);
        }

        public async Task<int> UpdateAsync(User entity)
        {
            return await _asyncUserRepository.UpdateAsync(entity);
        }

        public async Task<int> RemoveAsync(User entity)
        {
            return await _asyncUserRepository.RemoveAsync(entity);
        }

        public async Task<IList<User>> GetAllAsync()
        {
            return await _asyncUserRepository.GetAllAsync();
        }

        public async Task<IList<User>> GetBy(Expression<Func<User, bool>> predicate)
        {
            return await _asyncUserRepository.GetBy(predicate);
        }
    }

我有一些问题:

1. 是否可以使用 SQliteAsyncConnection 实现 UnitOfWork 模式。
2. 如何在存储库中执行提交和回滚。
3. 有什么我应该改进的吗？

提前致谢。

Answer 1

Is it possible to implement UnitOfWork pattern With SQliteAsyncConnection.

我想这在很大程度上取决于您的业务任务。你不能仅仅发明神奇地覆盖所有可能情况的抽象架构。异步数据处理本身并不是玩具。结合数据库，它很快就会变成难以管理的代码困惑。

How To perform Commit & RollBack within Repository.

好吧，首先您需要使用某种锁定机制来停止对 Repository 的访问。然后您需要等到所有异步操作完成。然后你提交/回滚并解锁。这当然是通用的，可能不适合您的工作流程。

Anything i should Improve ?

你告诉 ;)

实际上，我强烈建议不要使用通用的异步数据库访问。仅当您确实需要异步数据库操作时才使用异步数据库操作。通过主键获取一条记录不需要是异步的。它的速度足够快。