EF封装类 增加版，增加从缓存中查找数据方法，供参考！
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
本文转自 梦在旅途 博客园博客，原文链接：http://www.cnblogs.com/zuowj/p/4278537.html ，如需转载请自行联系原作者