EF封装类 增加版，增加从缓存中查找数据方法，供参考！
来源：互联网 发布：火眼金睛答题软件使用 编辑：程序博客网 时间：2024/04/30 12:56
这个类是抽象类，我这里增加了需要子类验证的方法ValidateEntity，方便扩展，若想直接使用该类，可以将该类更改成静态类，里面所有的方法都改成静态方法就可以直接调用了，可能有不足之处，欢迎大家在本文下面评论留言，共同完善，谢谢！
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using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Data.Objects.DataClasses;using ZBService.Model;using System.Linq.Expressions;using System.Web;namespace ZBService{ public abstract class ServiceBase<T>where T : EntityObject { /// <summary> /// EF上下文对象 /// </summary> protected mZhaoBiaoEntities zbEntities = new mZhaoBiaoEntities(); /// <summary> /// 判断是否存在 /// </summary> /// <param name="whereExpr"></param> /// <returns></returns> public bool Exist(Expression<Func<T,bool>> whereExpr) { return (this.Count(whereExpr) > 0); } /// <summary> /// 获取记录数 /// </summary> /// <param name="whereExpr"></param> /// <returns></returns> public int Count(Expression<Func<T,bool>> whereExpr) { return zbEntities.CreateObjectSet<T>().Where(whereExpr).Count(); } /// <summary> /// 查找实体对象 /// </summary> /// <param name="whereExpr"></param> /// <returns></returns> public T Find(Expression<Func<T, bool>> whereExpr) { return zbEntities.CreateObjectSet<T>().Where(whereExpr).FirstOrDefault(); } /// <summary> /// 从缓存中查找实体对象 /// </summary> /// <param name="whereExpr"></param> /// <param name="cacheKey"></param> /// <param name="expireTime"></param> /// <returns></returns> public T FindFromCache(Expression<Func<T, bool>> whereExpr, string cacheKey, DateTime expireTime) { T entity; object obj = HttpRuntime.Cache[cacheKey]; if (obj == null) { entity = this.Find(whereExpr); HttpRuntime.Cache.Insert(cacheKey, entity, null, expireTime, System.Web.Caching.Cache.NoSlidingExpiration); } else { entity = obj as T; } return entity; } /// <summary> /// 查找实体对象列表 /// </summary> /// <param name="whereExpr"></param> /// <returns></returns> public IEnumerable<T> FindList<TKey>(Expression<Func<T, bool>> whereExpr, Expression<Func<T, TKey>> orderbyExpr, int orderDirection) { return this.FindList<T, TKey>(whereExpr, t => t, orderbyExpr, orderDirection); } /// <summary> /// 从缓存中查找实体对象列表 /// </summary> /// <typeparam name="TKey"></typeparam> /// <param name="whereExpr"></param> /// <param name="orderbyExpr"></param> /// <param name="orderDirection"></param> /// <param name="cacheKey"></param> /// <param name="expireTime"></param> /// <returns></returns> public IEnumerable<T> FindListFromCache<TKey>(Expression<Func<T, bool>> whereExpr, Expression<Func<T, TKey>> orderbyExpr, int orderDirection,string cacheKey, DateTime expireTime) { return this.FindListFromCache(whereExpr, t => t, orderbyExpr, orderDirection, -1, cacheKey, expireTime); } /// <summary> /// 查找实体对象列表 /// </summary> /// <typeparam name="TResult"></typeparam> /// <typeparam name="TKey"></typeparam> /// <param name="whereExpr"></param> /// <param name="selectExpr"></param> /// <param name="orderbyExpr"></param> /// <param name="orderDirection"></param> /// <param name="returnCount"></param> /// <returns></returns> public IEnumerable<TResult> FindList<TResult, TKey>(Expression<Func<T, bool>> whereExpr, Expression<Func<T, TResult>> selectExpr, Expression<Func<TResult, TKey>> orderbyExpr,int orderDirection,int returnCount = -1) { var result = zbEntities.CreateObjectSet<T>().Where(whereExpr).Select(selectExpr); if (result != null && result.Count() > 0) { if (orderDirection > 0) { result = result.OrderByDescending(orderbyExpr); } else { result = result.OrderBy(orderbyExpr); } if (returnCount > 0) { result = result.Take(returnCount); } return result.ToList(); } return null; } /// <summary> /// 从缓存中查找对象列表 /// </summary> /// <typeparam name="TResult"></typeparam> /// <typeparam name="TKey"></typeparam> /// <param name="whereExpr"></param> /// <param name="selectExpr"></param> /// <param name="orderbyExpr"></param> /// <param name="orderDirection"></param> /// <param name="returnCount"></param> /// <param name="cacheKey"></param> /// <param name="expireTime"></param> /// <returns></returns> public IEnumerable<TResult> FindListFromCache<TResult, TKey>(Expression<Func<T, bool>> whereExpr, Expression<Func<T, TResult>> selectExpr, Expression<Func<TResult, TKey>> orderbyExpr,int orderDirection, int returnCount,string cacheKey, DateTime expireTime) { IEnumerable<TResult> resultList; object obj = HttpRuntime.Cache[cacheKey]; if (obj == null) { resultList = this.FindList(whereExpr, selectExpr,orderbyExpr, orderDirection,returnCount); HttpRuntime.Cache.Insert(cacheKey, resultList, null, expireTime, System.Web.Caching.Cache.NoSlidingExpiration); } else { resultList = obj as IEnumerable<TResult>; } return resultList; } /// <summary> /// 分页查找实体对象列表 /// </summary> /// <typeparam name="TResult"></typeparam> /// <typeparam name="TKey"></typeparam> /// <param name="whereExpr"></param> /// <param name="selectExpr"></param> /// <param name="orderbyExpr"></param> /// <param name="orderDirection"></param> /// <param name="pageSize"></param> /// <param name="pageNo"></param> /// <param name="recordCount"></param> /// <returns></returns> public IEnumerable<TResult> FindListByPage<TResult, TKey>(Expression<Func<T, bool>> whereExpr, Expression<Func<T, TResult>> selectExpr, Expression<Func<TResult, TKey>> orderbyExpr,int orderDirection,int pageSize,int pageNo,out int recordCount) { recordCount = 0; var result = zbEntities.CreateObjectSet<T>().Where(whereExpr).Select(selectExpr); if (result == null)return null; recordCount = result.Count(); if (pageNo > recordCount) pageNo = recordCount; if (pageNo <= 0) pageNo = 1; if (recordCount > 0) { if (recordCount > pageSize) { if (orderDirection > 0) { return result.OrderByDescending(orderbyExpr).Skip((pageNo - 1) * pageSize).Take(pageSize).ToList(); } else { return result.OrderBy(orderbyExpr).Skip((pageNo - 1) * pageSize).Take(pageSize).ToList(); } } else { if (orderDirection > 0) { return result.OrderByDescending(orderbyExpr).ToList(); } else { return result.OrderBy(orderbyExpr).ToList(); } } } return null; } /// <summary> /// 从缓存中分页查找实体对象列表 /// </summary> /// <typeparam name="TResult"></typeparam> /// <typeparam name="TKey"></typeparam> /// <param name="whereExpr"></param> /// <param name="selectExpr"></param> /// <param name="orderbyExpr"></param> /// <param name="orderDirection"></param> /// <param name="pageSize"></param> /// <param name="pageNo"></param> /// <param name="recordCount"></param> /// <param name="cacheKey"></param> /// <param name="expireTime"></param> /// <returns></returns> public IEnumerable<TResult> FindListByPageFromCache<TResult, TKey>(Expression<Func<T, bool>> whereExpr, Expression<Func<T, TResult>> selectExpr, Expression<Func<TResult, TKey>> orderbyExpr,int orderDirection,int pageSize,int pageNo,out int recordCount, string cacheKey, DateTime expireTime) { recordCount = 0; IQueryable<TResult> result; object obj = HttpRuntime.Cache[cacheKey]; if (obj == null) { result = zbEntities.CreateObjectSet<T>().Where(whereExpr).Select(selectExpr); } else { result = obj as IQueryable<TResult>; } if (result == null)return null; recordCount = result.Count(); if (pageNo > recordCount) pageNo = recordCount; if (pageNo <= 0) pageNo = 1; if (recordCount > 0) { if (recordCount > pageSize) { if (orderDirection > 0) { return result.OrderByDescending(orderbyExpr).Skip((pageNo - 1) * pageSize).Take(pageSize).ToList(); } else { return result.OrderBy(orderbyExpr).Skip((pageNo - 1) * pageSize).Take(pageSize).ToList(); } } else { if (orderDirection > 0) { return result.OrderByDescending(orderbyExpr).ToList(); } else { return result.OrderBy(orderbyExpr).ToList(); } } } return null; } /// <summary> /// 增加实体 /// </summary> /// <param name="entity"></param> public virtual void Add(T entity) { this.ValidateEntity(entity, ValidateMode.Add); zbEntities.CreateObjectSet<T>().AddObject(entity); } /// <summary> /// 增加实体列表 /// </summary> /// <param name="entities"></param> public virtual void AddList(IEnumerable<T> entities) { var objSet = zbEntities.CreateObjectSet<T>(); foreach (T entity in entities) { this.ValidateEntity(entity, ValidateMode.Add); objSet.AddObject(entity); } } /// <summary> /// 更新已分离实体,若未分离则不需要执行该方法 /// </summary> /// <param name="entity"></param> public virtual void Update(T entity) { this.ValidateEntity(entity, ValidateMode.Update); zbEntities.CreateObjectSet<T>().ApplyCurrentValues(entity); } /// <summary> /// 删除实体 /// </summary> /// <param name="entity"></param> public virtual void Delete(T entity) { this.ValidateEntity(entity, ValidateMode.Delete); zbEntities.CreateObjectSet<T>().DeleteObject(entity); } /// <summary> /// 删除实体 /// </summary> /// <param name="whereExpr"></param> public virtual void Delete(Expression<Func<T,bool>> whereExpr) { var objSet = zbEntities.CreateObjectSet<T>(); T entity = objSet.Where(whereExpr).Single(); //this.ValidateEntity(entity, ValidateMode.Delete); objSet.DeleteObject(entity); } /// <summary> /// 删除实体列表 /// </summary> /// <param name="entities"></param> public virtual void DeleteList(IEnumerable<T> entities) { var objSet = zbEntities.CreateObjectSet<T>(); foreach (T entity in entities) { //this.ValidateEntity(entity, ValidateMode.Delete); objSet.DeleteObject(entity); } } /// <summary> /// 提交保存所有变更操作 /// </summary> public void SubmitSave() { zbEntities.SaveChanges(); } /// <summary> /// 验证 /// </summary> /// <param name="entity"></param> /// <returns></returns> protected virtual void ValidateEntity(T entity, ValidateMode mode = ValidateMode.Add) { } /// <summary> /// 验证模式 /// </summary> protected enum ValidateMode { Add = 0, Update = 1, Delete = -1 } }}之前发表的文章详见：http://www.cnblogs.com/zuowj/p/4259515.html
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