使用entity framework 中code first封装实体类的基础功能

　1、定义一个增删改查基础类的接口　

public partial interface IRepositoryBase<T> where T : BaseModel
    {
        T GetById(Guid id);
        T GetById(int id);
        T GetById(long id);
        T GetById(string id);
        T GetFirstAsNoTracking(Expression<Func<T, bool>> predicate);
        List<T> Get(
            Expression<Func<T, Boolean>> predicate);
        List<T> GetAsNoTracking(Expression<Func<T, bool>> predicate);
        int Insert(T entity);
        int Update(T entity);
        int Delete(T entity);
        bool Exists(Guid ID);
        bool Exists(int ID);
        bool Exists(long ID);
        bool Exists(string ID);
        int Count(Expression<Func<T, bool>> predicate);
        T SingleOrDefault(Expression<Func<T, bool>> predicate);
        T SingleOrDefaultAsNoTracking(Expression<Func<T, bool>> predicate);
        DbContext GetSession();
    }

　2、基础实现类

public class EfRepository<T> : IRepositoryBase<T> where T : BaseModel
    {
        private IEntityPool entityBase;

        public EfRepository(IEntityPool EntityService)
        {
            if (EntityService == null)
            {
                throw new ArgumentNullException("context");
            }
            entityBase = EntityService;
        }
        public void Close()
        {
            if (entityBase == null)
            {
                throw new ArgumentNullException("context");
            }
            entityBase.CloseSession();
        }
        public T GetById(Guid id)
        {
            var db = entityBase.GetSession();
            T t = db.Set<T>().Find(id);
            return t;
        }
        public T GetById(int id)
        {
            var db = entityBase.GetSession();
            T t = db.Set<T>().Find(id);
            return t;
        }
        public T GetById(long id)
        {
            var db = entityBase.GetSession();
            T t = db.Set<T>().Find(id);
            return t;
        }
        public T GetById(string id)
        {
            var db = entityBase.GetSession();
            T t = db.Set<T>().Find(id);
            return t;
        }
        public T GetFirstAsNoTracking(Expression<Func<T, bool>> predicate)
        {
            var db = entityBase.GetSession();
            T t = db.Set<T>().AsNoTracking().FirstOrDefault(predicate);
            return t;
        }
        public int Insert(T entity)
        {
            var db = entityBase.GetSession();
            db.Set<T>().Add(entity);
            int flg = db.SaveChanges();
            return flg;
        }
        public int Update(T entity)
        {
            var db = entityBase.GetSession();
            int flg = -1;
            if (db.Entry<T>(entity).State == EntityState.Modified)
            {

            }
            else if (db.Entry<T>(entity).State == EntityState.Detached)
            {
                try
                {
                    db.Set<T>().Attach(entity);
                    db.Entry<T>(entity).State = EntityState.Modified;
                }
                catch (InvalidOperationException)
                {
                    T old = GetById(entity.GetHashCode());
                    db.Entry(old).CurrentValues.SetValues(entity);
                }
            }
            flg = db.SaveChanges();
            return flg;  
        }
        public int Delete(T entity)
        {
            var db = entityBase.GetSession();
            db.Entry<T>(entity).State = EntityState.Deleted;
            return db.SaveChanges();
        }
        public bool Exists(Guid ID) 
        {
            var db = entityBase.GetSession();
            bool flg = db.Set<T>().Find(ID) != null;
            return flg;
        }
        public bool Exists(int ID)
        {
            var db = entityBase.GetSession();
            bool flg = db.Set<T>().Find(ID) != null;
            return flg;
        }
        public bool Exists(long ID)
        {
            var db = entityBase.GetSession();
            bool flg = db.Set<T>().Find(ID) != null;
            return flg;
        }
        public bool Exists(string ID)
        {
            var db = entityBase.GetSession();
            bool flg = db.Set<T>().Find(ID) != null;
            return flg;
        }
        public int Count(Expression<Func<T, bool>> predicate) 
        {
            var db = entityBase.GetSession();
            int count = db.Set<T>().Where(predicate).Count();
            return count;
        }
        public List<T> Get(Expression<Func<T, bool>> predicate)
        {
            var db = entityBase.GetSession();
            List<T> list = db.Set<T>().Where(predicate).ToList();
            return list;
        }
        public List<T> GetAsNoTracking(Expression<Func<T, bool>> predicate)
        {
            var db = entityBase.GetSession();
            List<T> list = db.Set<T>().AsNoTracking().Where(predicate).ToList();
            return list;
        }
        public T SingleOrDefault(Expression<Func<T, bool>> predicate)
        {
            var db = entityBase.GetSession();
            T t = db.Set<T>().SingleOrDefault<T>(predicate);
            return t;
        }
        public T SingleOrDefaultAsNoTracking(Expression<Func<T, bool>> predicate)
        {
            var db = entityBase.GetSession();
            T t = db.Set<T>().AsNoTracking().SingleOrDefault<T>(predicate);
            return t;
        }

        public void ReLoad(DbContext db) {
            var entitiesToRefresh = db.Set<T>().Local;
            var objectContext = ((IObjectContextAdapter)db).ObjectContext;
            objectContext.Refresh(RefreshMode.StoreWins, entitiesToRefresh);
        }
        public DbContext GetSession() 
        {
            return entityBase.GetSession();
        }
    }

3、各种业务类继承基础类并实现自己的特定接口，其中数据库上下文池接口IEntityPool  使用IOC注入  

public class ResourcesRepository : EfRepository<Pip_ResourcesModel>, IResourcesRepository
    {
        public ResourcesRepository(IEntityPool EntityService)
            : base(EntityService) { }
        public List<Pip_ResourcesModel> GetAllResources()
        {
            return this.GetSession().Set<Pip_ResourcesModel>().AsNoTracking().OrderBy(model=>model.OrderID).ToList<Pip_ResourcesModel>();
        }

        public List<Pip_ResourcesModel> GetAllDirResources()
        {
            var resList = from res in this.GetSession().Set<Pip_ResourcesModel>().AsNoTracking().OrderBy(model => model.OrderID).ToList() where (res.ResourceType == "dir") select res;
            return resList.ToList();
        }
        public void DeleteResources(int[] ids)
        {
            var dbset = this.GetSession();
            var resList = from res in dbset.Set<Pip_ResourcesModel>() where ids.Contains(res.ResourceID) select res;
            dbset.Set<Pip_ResourcesModel>().RemoveRange(resList);
            dbset.SaveChanges();
        }
        public void DeleteResource(int id)
        {
            Pip_ResourcesModel model = this.SingleOrDefaultAsNoTracking(r=>r.ResourceID==id);
            if(default(Pip_ResourcesModel) != model){
                this.Delete(model);
            }
        }
        public Pip_ResourcesModel GetByIDAsNoTracking(int id) {
            return this.GetFirstAsNoTracking(s => s.ResourceID == id);
        }
    }

<object id="ResourcesRepositoryService" type="Com.JingPai.Pip.Repository.Power.ResourcesRepository,Com.JingPai.Pip.Repository">
    <constructor-arg name="EntityService" ref="PipMainEntityService"/>
  </object>

<object id="PipMainEntityService" type="Com.JingPai.Pip.Model.Pool.PipEntityPool, Com.JingPai.Pip.Model" singleton="false" >
  </object>