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
}
}
}
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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
