上一节我们讲到对EF（EntityFramework）的初步封装，任何事情都不可能一蹴而就，通过大量的实际项目的实战，也发现了其中的各种问题。在这一章中，我们对上一章的EF_Helper_DG进行优化，主要优化点如下：
1.由DB实体单例模式改为从缓存中获取；
2.加入服务器缓存，协助查询，提升查询性能；
3.优化CUD操作方法的执行方式；
下面直接展示新的EF_Helper_DG 代码：
using LinqKit; //AsExpandable() in linqkit.dll
using System;
using System.Linq;
using System.Linq.Expressions;
using System.Data.Entity;
using System.Transactions;
using QX_Frame.Helper_DG.Configs;
namespace QX_Frame.Helper_DG
{
/* time: 2016-10-30 15:26:05
author: qixiao
*/
/// <summary>
/// EntityFramework CodeFirst Helper
/// </summary>
/// <typeparam name="Db">DbContext</typeparam>
public abstract class EF_Helper_DG<Db> where Db : DbContext
{
/*the singleton Db */
//private volatile static Db db = null; //volatile find Db in memory not in cache
#region The Singleton to new DBEntity_DG
//private static readonly object lockHelper = new object();
//static EF_Helper_DG()
//{
// if (db == null)
// {
// lock (lockHelper)
// {
// if (db == null)
// db = System.Activator.CreateInstance<Db>();
// }
// }
// //close the Validate of EF OnSaveEnabled
// db.Configuration.ValidateOnSaveEnabled = false;
//}
#endregion
#region get current dbContext
public static DbContext GetCurrentDbContext()
{
//method 1 : CallContext 该方法有有时候第一次访问不到的bug
//CallContext：是线程内部唯一的独用的数据槽（一块内存空间）
//Db dbContext = CallContext.GetData("DbContext") as Db;
//if (dbContext == null) //线程在内存中没有此上下文
//{
// //create a dbContext to memory if dbContext has not exist
// dbContext = System.Activator.CreateInstance<Db>();
// CallContext.SetData("DbContext", dbContext);
//}
//method 2 :
Db dbContext = Cache_Helper_DG.Cache_Get("dbContext") as Db;
if (dbContext == null)
{
//create a dbContext to memory if dbContext has not exist
dbContext = System.Activator.CreateInstance<Db>();
Cache_Helper_DG.Cache_Add("dbContext",dbContext);
}
return dbContext;
}
#endregion
#region Cache Strategy
/// <summary>
/// edit data cache must update
/// </summary>
public static void CacheChanges<T>()
{
if (QX_Frame_Helper_DG_Config.Cache_IsCache)
{
Cache_Helper_DG.Cache_Delete(nameof(T));
}
}
/// <summary>
/// query cache
/// </summary>
/// <typeparam name="T"></typeparam>
/// <returns></returns>
public static IQueryable<T> GetIQuerybleByCache<T>() where T : class
{
if (QX_Frame_Helper_DG_Config.Cache_IsCache)
{
IQueryable<T> iqueryable = Cache_Helper_DG.Cache_Get(nameof(T)) as IQueryable<T>;
if (iqueryable == null)
{
DbContext db = GetCurrentDbContext();
iqueryable = db.Set<T>().AsExpandable();
Cache_Helper_DG.Cache_Add(nameof(T), iqueryable, null, DateTime.Now.AddMinutes(QX_Frame_Helper_DG_Config.Cache_CacheExpirationTime_Minutes), TimeSpan.Zero);
}
return iqueryable;
}
else
{
DbContext db = GetCurrentDbContext();
return db.Set<T>().AsExpandable();
}
}
#endregion
#region Add
public static Boolean Add<T>(T entity) where T : class
{
DbContext db = GetCurrentDbContext();
CacheChanges<T>();
db.Entry<T>(entity).State = EntityState.Added;
;
}
public static Boolean Add<T>(T entity, out T outEntity) where T : class
{
DbContext db = GetCurrentDbContext();
CacheChanges<T>();
db.Entry<T>(entity).State = EntityState.Added;
outEntity = entity;
;
}
public static Boolean Add<T>(IQueryable<T> entities) where T : class
{
DbContext db = GetCurrentDbContext();
CacheChanges<T>();
db.Set<T>().AddRange(entities);
;
}
#endregion
#region Update
public static Boolean Update<T>(T entity) where T : class
{
DbContext db = GetCurrentDbContext();
CacheChanges<T>();
if (db.Entry<T>(entity).State == EntityState.Detached)
{
db.Set<T>().Attach(entity);
db.Entry<T>(entity).State = EntityState.Modified;
}
else
{
db.SaveChanges();
return true;
}
;
}
public static Boolean Update<T>(T entity, out T outEntity) where T : class
{
DbContext db = GetCurrentDbContext();
CacheChanges<T>();
outEntity = entity;
if (db.Entry<T>(entity).State == EntityState.Detached)
{
db.Set<T>().Attach(entity);
db.Entry<T>(entity).State = EntityState.Modified;
}
else
{
db.SaveChanges();
return true;
}
;
}
#endregion
#region Delete
public static Boolean Delete<T>(T entity) where T : class
{
DbContext db = GetCurrentDbContext();
CacheChanges<T>();
db.Set<T>().Attach(entity);
db.Entry<T>(entity).State = EntityState.Deleted;
;
}
public static Boolean Delete<T>(IQueryable<T> entities) where T : class
{
DbContext db = GetCurrentDbContext();
CacheChanges<T>();
db.Set<T>().RemoveRange(entities);
;
}
public static Boolean Delete<T>(Expression<Func<T, bool>> deleteWhere) where T : class
{
DbContext db = GetCurrentDbContext();
CacheChanges<T>();
IQueryable<T> entitys = GetIQuerybleByCache<T>().Where(deleteWhere);
/**
* change code 2017-5-6 11:11:19 qixiao
* entitys.ForEach(m => db.Entry<T>(m).State = EntityState.Deleted);
**/
entitys.ForEachAsync(m => db.Entry<T>(m).State = EntityState.Deleted);
;
}
#endregion
#region Select
public static Boolean Exist<T>(Expression<Func<T, Boolean>> selectWhere) where T : class
{
return GetIQuerybleByCache<T>().Where(selectWhere).FirstOrDefault<T>() == null ? false : true;
}
public static T selectSingle<T>(Expression<Func<T, Boolean>> selectWhere) where T : class
{
return GetIQuerybleByCache<T>().Where(selectWhere).FirstOrDefault<T>();
}
public static IQueryable<T> selectAll<T>() where T : class
{
return GetIQuerybleByCache<T>();
}
public static IQueryable<T> selectAll<T>(out int Count) where T : class
{
Count = GetIQuerybleByCache<T>().Count();
return GetIQuerybleByCache<T>();
}
public static IQueryable<T> selectAll<T, TKey>(Expression<Func<T, TKey>> orderBy, Boolean isDESC = false) where T : class
{
if (isDESC)
return GetIQuerybleByCache<T>().OrderByDescending(orderBy);
else
return GetIQuerybleByCache<T>().OrderBy(orderBy);
}
public static IQueryable<T> selectAll<T, TKey>(Expression<Func<T, TKey>> orderBy, out int Count, Boolean isDESC = false) where T : class
{
Count = GetIQuerybleByCache<T>().Count();
if (isDESC)
return GetIQuerybleByCache<T>().OrderByDescending(orderBy);
else
return GetIQuerybleByCache<T>().OrderBy(orderBy);
}
public static IQueryable<T> selectAll<T>(Expression<Func<T, Boolean>> selectWhere) where T : class
{
return GetIQuerybleByCache<T>().Where(selectWhere);
}
public static IQueryable<T> selectAll<T>(Expression<Func<T, Boolean>> selectWhere, out int Count) where T : class
{
var IQueryable = GetIQuerybleByCache<T>().Where(selectWhere);
Count = IQueryable.Count();
return IQueryable;
}
public static IQueryable<T> selectAll<T, TKey>(Expression<Func<T, TKey>> orderBy, Expression<Func<T, Boolean>> selectWhere, Boolean isDESC = false) where T : class
{
if (isDESC)
return GetIQuerybleByCache<T>().Where(selectWhere).OrderByDescending(orderBy);
else
return GetIQuerybleByCache<T>().Where(selectWhere).OrderBy(orderBy);
}
public static IQueryable<T> selectAll<T, TKey>(Expression<Func<T, TKey>> orderBy, Expression<Func<T, Boolean>> selectWhere, out int Count, Boolean isDESC = false) where T : class
{
var IQueryable = GetIQuerybleByCache<T>().Where(selectWhere);
Count = IQueryable.Count();
if (isDESC)
return IQueryable.OrderByDescending(orderBy);
else
return IQueryable.OrderBy(orderBy);
}
public static IQueryable<T> selectAllPaging<T, TKey>(int pageIndex, int pageSize, Expression<Func<T, TKey>> orderBy, Boolean isDESC = false) where T : class
{
var IQueryable = GetIQuerybleByCache<T>();
if (isDESC)
< ? : pageIndex - ) * (pageSize < ? : pageSize)).Take(pageSize < ? : pageSize);
else
< ? : pageIndex - ) * (pageSize < ? : pageSize)).Take(pageSize < ? : pageSize);
}
public static IQueryable<T> selectAllPaging<T, TKey>(int pageIndex, int pageSize, Expression<Func<T, TKey>> orderBy, out int Count, Boolean isDESC = false) where T : class
{
var IQueryable = GetIQuerybleByCache<T>();
Count = IQueryable.Count();
if (isDESC)
< ? : pageIndex - ) * (pageSize < ? : pageSize)).Take(pageSize < ? : pageSize);
else
< ? : pageIndex - ) * (pageSize < ? : pageSize)).Take(pageSize < ? : pageSize);
}
public static IQueryable<T> selectAllPaging<T, TKey>(int pageIndex, int pageSize, Expression<Func<T, TKey>> orderBy, Expression<Func<T, Boolean>> selectWhere, Boolean isDESC = false) where T : class
{
var IQueryable = GetIQuerybleByCache<T>().Where(selectWhere);
if (isDESC)
< ? : pageIndex - ) * (pageSize < ? : pageSize)).Take(pageSize < ? : pageSize);
else
< ? : pageIndex - ) * (pageSize < ? : pageSize)).Take(pageSize < ? : pageSize);
}
public static IQueryable<T> selectAllPaging<T, TKey>(int pageIndex, int pageSize, Expression<Func<T, TKey>> orderBy, Expression<Func<T, Boolean>> selectWhere, out int Count, Boolean isDESC = false) where T : class
{
var IQueryable = GetIQuerybleByCache<T>().Where(selectWhere);
Count = IQueryable.Count();
if (isDESC)
< ? : pageIndex - ) * (pageSize < ? : pageSize)).Take(pageSize < ? : pageSize);
else
< ? : pageIndex - ) * (pageSize < ? : pageSize)).Take(pageSize < ? : pageSize);
}
#endregion
#region Transaction
public static void Transaction(Action action)
{
using (TransactionScope trans = new TransactionScope())
{
action();
trans.Complete();
}
}
#endregion
#region ExecuteSqlCommand
public static void ExecuteSqlCommand(string sqlCommand)
{
DbContext db = GetCurrentDbContext();
db.Database.ExecuteSqlCommand(sqlCommand);
}
public static void ExecuteSqlCommand(string sqlCommand, params object[] parameters)
{
DbContext db = GetCurrentDbContext();
db.Database.ExecuteSqlCommand(sqlCommand, parameters);
}
#endregion
}
}上述代码为当前版本的EF_Helper_DG代码，当然欢迎所有的同行们优化补充哦~