dhl:vs2010 -EF4.0 数据层： 通过反射返回泛型的工厂

转载 于 2010-09-16 11:06:00 发布 · 97 阅读 · 0 ·
CC 4.0 BY-SA版权
原文链接：http://www.cnblogs.com/dudu837/archive/2010/09/16/1827905.html
文章标签：

#数据库

本文介绍了一个基于VS2010的项目中数据层的设计思路，采用LinqToEntity并结合接口和泛型实现灵活扩展。通过具体代码示例展示了如何使用接口IUserRepository和泛型接口IRepository<T>进行数据操作。

最近用vs2010做项目，想到了数据层Linq To Entity的实现和以后的扩展，想以接口的形式实现。

总体架构图：

2010091611052366.jpg

数据层Data：

普通的数据操作数据层：

接口IUserRepository：

 

    public interface IUserRepository
    {
        IList<UserAccount> GetCommonInterestsUser(int UIN);
void  AddUser();
        ....
    }




接口的实现类UserRepository:




public class UserRepository:IUserRepository
    {
        private TaoXueDBEntities _TaoXueDBEntities = new TaoXueDBEntities();
        public IList<UserAccount> GetCommonInterestsUser(int UIN)
        {
            return _TaoXueDBEntities.GetMyLike(UIN).ToList();
        }
    }





 


工厂:




 public class RepositoryFactory
    {
        private readonly IDictionary<String, Object> factory = new Dictionary<String, Object>();
        /// <summary>
        /// 获取用户Repository 
        /// </summary>
        /// <returns>用户仓储接口</returns>
        public IUserRepository GetUserRepository()
        {
            string className = "Taoxue.Data.UserRepository";
            if (factory.ContainsKey(className)) return factory[className] as UserRepository;
            IUserRepository repo = Activator.CreateInstance(Type.GetType(className)) as IUserRepository;
            factory.Add(className, repo);
            return repo;
        }
}





 


 


泛型的数据接口：


 


ContractedBlock.gifExpandedBlockStart.gif代码



    public interface IRepository<T> where T : class
    {       
int Add(T entity);
int Count(ICriteria criteria);
int Delete(T entity);
int ExecuteStoreCommand(string commandText, params ObjectParameter[] paramete);
        ObjectResult<T> ExecuteStoreQuery(string commandText, params ObjectParameter[] paramete);
        IList<T> Find(ICriteria criteria, int page, int pageSize, OrderBy orderExpr);
        IList<T> FindAll();
        IList<T> FindAll(Func<T, bool> exp);
        ObjectSet<T> FindQuerySet() ;
        ObjectContext GetObjectContext();
        ObjectQuery<T> GetQuery(string query, params ObjectParameter[] parameter);
int SaveChanges();
int Update(T entity);
    }






 


泛型的实现类：




 public class Repository<T> : IRepository<T> where T : class
    {

        private ObjectContext _objectContext = null;
        #region objectContext
        /// <summary>
        /// 获得提供用于查询和使用对象形式的实体数据功能
        /// </summary>
        /// <returns>数据库上下文</returns>
        public virtual ObjectContext GetObjectContext()
        {
            return new TaoXueDBEntities();
        }
        #endregion


        public Repository()
        {
        }
        /// <summary>
        /// 按条件查询所有对象
        /// </summary>
        /// <param name="exp">表达式</param>
        /// <returns>查询结果</returns>
        public IList<T> FindAll(Func<T, bool> exp)
        {
            using (var objectContext = GetObjectContext())
            {
                var result = objectContext.CreateObjectSet<T>().Where(exp).ToList();
                return result;
            }
        }
        /// <summary>
        /// 返回所有对象
        /// </summary>
        /// <returns></returns>
        public IList<T> FindAll()
        {
            using (var objectContext = GetObjectContext())
            {
                var v = objectContext.CreateObjectSet<T>();
                return v.ToList();
            }
        }
        /// <summary>
        /// 获取数据集实例，用于查询，修改，添加，删除
        /// </summary>
        /// <returns></returns>
        public ObjectSet<T> FindQuerySet()
        {
            if (_objectContext == null)
            {
                _objectContext = GetObjectContext();
            }

            var result = _objectContext.CreateObjectSet<T>();
            return result;
        }

        /// <summary>
        /// ESQL查询,绑定了EF框架
        /// </summary>
        /// <param name="query">ESQL语句</param>
        /// <param name="parameter">参数(可选)</param>
        /// <returns></returns>
        public ObjectQuery<T> GetQuery(string query, params ObjectParameter[] parameter)
        {
            using (var objectContext = GetObjectContext())
            {
                var result = objectContext.CreateQuery<T>(query, parameter);
                return result;
            }
        }
        /// <summary>
        /// 执行数据源语句(如SQL)，返回影响的行数
        /// </summary>
        /// <param name="commandText">查询语句</param>
        /// <param name="parameter">参数(可选)</param>
        /// <returns></returns>
        public int ExecuteStoreCommand(string commandText, params ObjectParameter[] paramete)
        {
            if (string.IsNullOrEmpty(commandText))
            {
                return -1;
            }
            using (var objectContext = GetObjectContext())
            {
                var result = objectContext.ExecuteStoreCommand(commandText, paramete);
                return result;
            }
        }
        /// <summary>
        /// 执行数据源查询语句(如SQL)，获得数据查询列表
        /// </summary>
        /// <param name="commandText">查询语句</param>
        /// <param name="parameter">参数(可选)</param>
        /// <returns></returns>
        public ObjectResult<T> ExecuteStoreQuery(string commandText, params ObjectParameter[] paramete)
        {
            using (var objectContext = GetObjectContext())
            {
                var result = objectContext.ExecuteStoreQuery<T>(commandText, paramete);
                return result;
            }
        }
       
        /// <summary>
        /// 添加对象
        /// </summary>
        /// <param name="entity"></param>
        /// <returns>修改成功的对象数</returns>
        public int Add(T entity)
        {
            using (var objectContext = GetObjectContext())
            {
                objectContext.CreateObjectSet<T>().AddObject(entity);
                var result = objectContext.SaveChanges();
                return result;
            }
        }
        /// <summary>
        /// 删除对象
        /// </summary>
        /// <param name="entity">将被删除的对象</param>
        /// <returns>删除的数量</returns>
        public int Delete(T entity)
        {
            //objectContext.Attach(entity);            
            using (var objectContext = GetObjectContext())
            {
                try
                {
                    objectContext.CreateObjectSet<T>().Attach(entity);
                    objectContext.CreateObjectSet<T>().DeleteObject(entity);
                }
                catch (Exception e)
                {
                    //todo:log it e
                }
                var result = objectContext.SaveChanges();
                return result;
            }
        }
        /// <summary>
        /// 提交所有修改
        /// </summary>
        public int SaveChanges()
        {
            if (_objectContext != null)
                return _objectContext.SaveChanges();
            else
                return -1;
        }
        /// <summary>
        /// 更新对象
        /// </summary>
        /// <param name="entity"></param>
        /// <returns></returns>
        public int Update(T entity)
        {
            using (var objectContext = GetObjectContext())
            {
                objectContext.CreateObjectSet<T>().Attach(entity);                  
                //objectContext.SetAllModified(entity);
                objectContext.ObjectStateManager.ChangeObjectState(entity, EntityState.Modified);//EF4 新语法
                try
                {
                    var result = objectContext.SaveChanges();
                    return result;
                }
                catch (OptimisticConcurrencyException e)
                {
                    objectContext.Refresh(RefreshMode.ClientWins, entity); // Last in wins
                    //logger.Write(e);
                    var result = objectContext.SaveChanges();
                    return result;
                }
            }

            //using (var ctx = new AdventureWorksEntities())
            //{
            //    // 先 ApplyChanges() 再 ChangeObjectState(), ChangeRelationshipState()
            //    ctx.ProductCategories.ApplyChanges(category);
            //    ctx.ObjectStateManager.ChangeObjectState(category, EntityState.Modified);

            //    return ctx.SaveChanges();
            //}
        }
}







 


 


工厂RepositoryFactory：


 


ContractedBlock.gifExpandedBlockStart.gif代码



public class RepositoryFactory
    {
private readonly IDictionary<String, Object> factory = new Dictionary<String, Object>();

#region RepositoryFactory 为单例
/// <summary>
/// RepositoryFactory 为单例模式
/// </summary>
        private static RepositoryFactory Instance;
private RepositoryFactory()
        {
        }
/// <summary>
/// 获取Repository工厂实例
/// </summary>
/// <returns>Repository工厂实例</returns>
        public static RepositoryFactory GetInstance()
        {
if (Instance == null) Instance = new RepositoryFactory();
return Instance;
        }
#endregion

#region 工厂方法：通过反射返回泛型数据操作接口的实现类
/// <summary>
/// 获取实体类的Repository的接口IRepository
/// </summary>
/// <typeparam name="T">实体Entity</typeparam>
/// <returns>泛型IRepository</returns>
        public IRepository<T> GetRepository<T>() where T : class
        {
            Type t = typeof(T);
if (factory.ContainsKey("Repository" + t.FullName)) return factory["Repository" + t.FullName] as IRepository<T>;
string className = "Taoxue.Data.Repository`1";
            className += "[[" + t.FullName + "," + t.Assembly.FullName + "]]";
            Type type = Type.GetType(className);
            IRepository<T> repo = Activator.CreateInstance(type) as IRepository<T>;
            factory.Add("Repository" + t.FullName, repo);
return repo;
        }
#endregion

#region 工厂方法：通过反射返回其他数据操作接口的实现类
/// <summary>
/// 获取用户Repository 
/// </summary>
/// <returns>用户仓储接口</returns>
        public IUserRepository GetUserRepository()
        {
string className = "Taoxue.Data.UserRepository";
if (factory.ContainsKey(className)) return factory[className] as UserRepository;
            IUserRepository repo = Activator.CreateInstance(Type.GetType(className)) as IUserRepository;
            factory.Add(className, repo);
return repo;
        }

public ITaokeRepository GetTaoxueRepository()
        {
const string className = "Taoxue.Data.TaokeRepository";
if (factory.ContainsKey(className)) return factory[className] as ITaokeRepository;
            var repo = Activator.CreateInstance(Type.GetType(className)) as ITaokeRepository;
            factory.Add(className, repo);
return repo;
        }
#endregion
    }






 


  上层业务的调用：


            IRepository<Lesson> repository = RepositoryFactory.GetInstance().GetRepository<Lesson>();
            IList<Lesson> listAll = repository.FindAll();
            return listAll;


 


转载于:https://www.cnblogs.com/dudu837/archive/2010/09/16/1827905.html

                

        




    

    
  



    

      

        

            

              
                
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