首次接触仓储的概念来自Eric Evans 的经典著作《领域驱动设计－软件核心复杂性应对之道》，但书中没有具体实现。如何实现仓储模式，在我这几年的使用过程中也积累了一些具体的实施经验。根据项目的大小、可维护性、可扩展性，以及并发我们可以做以下几种设计；

 

1、项目小，扩展性差

public interface IRepository<T> where T : class,new()
    {
        /// <summary>
        /// 创建对象
        /// </summary>
        /// <param name="model"></param>
        /// <returns></returns>
        T Create(T model);

        /// <summary>
        /// 更新对象
        /// </summary>
        /// <param name="model"></param>
        /// <returns></returns>
        T Update(T model);

        /// <summary>
        /// 根据对象全局唯一标识检索对象
        /// </summary>
        /// <param name="guid"></param>
        /// <returns></returns>
        T Retrieve(Guid guid);


        /// <summary>
        /// 根据条件表达式检索对象
        /// </summary>
        /// <param name="expression">条件表达式</param>
        /// <returns></returns>
        /// <exception cref = "ArgumentNullException" > source 为 null</exception>
        T Retrieve(Expression<Func<T, bool>> expression);

        /// <summary>
        /// 根据对象全局唯一标识删除对象
        /// </summary>
        /// <param name="guid">对象全局唯一标识</param>
        /// <returns>删除的对象数量</returns>
        int Delete(Guid guid);

        /// <summary>
        /// 根据对象全局唯一标识集合删除对象集合
        /// </summary>
        /// <param name="guids">全局唯一标识集合</param>
        /// <returns>删除的对象数量</returns>
        int BatchDelete(IList<Guid> guids);

        List<T> GetAll();

        List<T> GetAll(Expression<Func<T, bool>> expression, Expression<Func<T, dynamic>> sortPredicate, SortOrder sortOrder, int skip, int take, out int total);
    }

IRepository接口包含了CRUD操作，如果在业务中还需要扩展，只需在IRepository接口中添加即可。

public class RepositoryImpl<T> : IRepository<T> where T : class, new()
    {
        protected readonly string ConnectionString;

        protected RepositoryImpl(ISqlHelp sqlHelp)
        {
            ConnectionString = sqlHelp.SQLConnectionString();
        }

        public int BatchDelete(IList<Guid> guids)
        {
            using (var dbcontext = new DbContext(ConnectionString))
            {
                foreach (var item in guids)
                {
                    var model = dbcontext.Set<T>().Find(item);
                    dbcontext.Entry(model).State = EntityState.Deleted;
                }
                return dbcontext.SaveChanges();
            }
        }

        public T Create(T model)
        {
            using (var dbcontext = new DbContext(ConnectionString))
            {
                dbcontext.Entry(model).State = EntityState.Added;
                var createRowCount = dbcontext.SaveChanges();
                return createRowCount > 0 ? model : null;
            }
        }

        /// <summary>
        /// 删除模型
        /// </summary>
        /// <param name="guid">指定的全局标识</param>
        /// <returns>删除数量</returns>
        /// <exception cref="ArgumentOutOfRangeException"></exception>
        public int Delete(Guid guid)
        {
            using (var dbcontext = new DbContext(ConnectionString))
            {
                var model = dbcontext.Set<T>().Find(guid);
                if (model == null) throw new ArgumentOutOfRangeException(nameof(guid));
                dbcontext.Entry(model).State = EntityState.Deleted;
                return dbcontext.SaveChanges();
            }
        }

        public List<T> GetAll()
        {
            using (var dbcontext = new DbContext(ConnectionString))
            {
                ret