Entity Framework本身的增删改查其实 已经很方便了，不过做项目的时候用的多了也就觉得有点累了，每个业务实体基本上都涉及到到了增删改查这四个基本的要素，至于封装每个公司可能都不一样，接口，设计模式都用的眼花缭乱，我闲来没事就搞个简单的封装Helper，Github上也有关于EF的扩展Libray，具体没有用过，公司的有自己的封装，自己也没怎么弄，具体地址:https://github.com/loresoft/EntityFramework.Extended.
首先来看段代码，model和context是从数据中直接生成，你可以选择自己习惯的方式:
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//新增
User addUser =
new
User();
addUser.PersonID =
3
;
addUser.UserName =
"keso"
;
dbContext.Entry<User>(addUser).State = EntityState.Added;
dbContext.SaveChanges();
//修改
User updateUser =
new
User();
dbContext.Users.Where(item => item.ID ==
2
).OrderBy(item => item.ID);
updateUser.UserName = updateUser.UserName +
"测试"
;
dbContext.Entry<User>(updateUser).State = EntityState.Modified;
dbContext.SaveChanges();
//删除
User delUser = dbContext.Users.Where(item => item.ID ==
2
).First();
dbContext.Entry<User>(delUser).State = EntityState.Deleted;
dbContext.SaveChanges();
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如果每个业务实体都这么写一遍，估计公司水准有待提高，而且开发的也该跳起来骂人，本人只是简单封装下新建一个EFHelper，实际开发会封装的更多，不过底层处理是不变的
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class
EFHelpler<T> where T :
class
{
//...
}
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新增
方法:
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/// <summary>
/// 实体新增
/// </summary>
/// <param name="model"></param>
public
void
add(params T[] paramList)
{
foreach (var model in paramList)
{
dbContext.Entry<T>(model).State = EntityState.Added;
}
dbContext.SaveChanges();
}
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调用:
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EFHelpler<User> helper =
new
EFHelpler<User>();
BaseContext dbContext =
new
BaseContext();
//新增
List<User> listUser =
new
List<User>();
for
(
int
i =
0
; i <
2
; i++)
{
User user =
new
User();
user.PersonID = i;
user.UserName =
"FlyElehant"
+ i;
listUser.Add(user);
}
helper.add(listUser.ToArray());
Console.WriteLine(
"新增成功"
);
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查询
查询分了两种，一种是简单的查询，一种是分页的：
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/// <summary>
/// 实体查询
/// </summary>
public
IEnumerable<T> getSearchList(System.Linq.Expressions.Expression<Func<T, bool>> where)
{
return
dbContext.Set<T>().Where(where);
}
/// <summary>
/// 实体分页查询
/// </summary>
/// <typeparam name="TKey"></typeparam>
/// <param name="where"></param>
/// <param name="orderBy"></param>
/// <param name="pageSize"></param>
/// <param name="pageIndex"></param>
/// <returns></returns>
public
IEnumerable<T> getSearchListByPage<TKey>(Expression<Func<T, bool>> where, Expression<Func<T, TKey>> orderBy,
int
pageSize,
int
pageIndex)
{
return
dbContext.Set<T>().Where(where).OrderByDescending(orderBy).Skip((pageIndex -
1
) * pageSize).Take(pageSize);
}
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简单调用，第二个方式除了分页之外，主要是查询的时候指定一定OrderBy的类型，也就是TKey:
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var query = helper.getSearchList(item => item.UserName.Contains(
"keso"
));
var queryMulti = helper.getSearchListByPage<
int
>(item => item.UserName.Contains(
"FlyElehant"
), order => order.PersonID,
2
,
1
);
query = queryMulti;
foreach (User user in query)
{
Console.WriteLine(user.UserName);
}
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修改
修改代码稍微读了几行，主要是用到了一下反射:
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/// <summary>
/// 按照条件修改数据
/// </summary>
/// <param name="where"></param>
/// <param name="dic"></param>
public
void
update(Expression<Func<T, bool>> where, Dictionary<string, object> dic)
{
IEnumerable<T> result = dbContext.Set<T>().Where(where).ToList();
Type type = typeof(T);
List<PropertyInfo> propertyList = type.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance).ToList();
//遍历结果集
foreach (T entity in result)
{
foreach (PropertyInfo propertyInfo in propertyList)
{
string propertyName = propertyInfo.Name;
if
(dic.ContainsKey(propertyName))
{
//设置值
propertyInfo.SetValue(entity, dic[propertyName],
null
);
}
}
}
dbContext.SaveChanges();
}
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调用:
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Dictionary<string,object> dic=
new
Dictionary<string,object>();
dic.Add(
"PersonID"
,
2
);
dic.Add(
"UserName"
,
"keso"
);
helper.update(item => item.UserName.Contains(
"keso"
), dic);
Console.WriteLine(
"修改成功"
);
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删除
方法:
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/// <summary>
/// 实体删除
/// </summary>
/// <param name="model"></param>
public
void
delete(params T[] paramList)
{
foreach (var model in paramList)
{
dbContext.Entry<T>(model).State = EntityState.Deleted;
}
dbContext.SaveChanges();
}
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调用:
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var query = helper.getSearchList(item => item.UserName.Contains(
"keso"
));
helper.delete(query.ToArray());
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完整的EFHelper:
个人Demo难免有表达不当或者技术失误的地方，如有不当，请多多指出，感激不尽~
本文转自Fly_Elephant博客园博客，原文链接：http://www.cnblogs.com/xiaofeixiang/p/4188600.html，如需转载请自行联系原作者
