在linq中创建懒惰是正确的吗? [英] create lazy in linq is correct?

问题描述

专家，
我有一个大问题，请帮我，我在asp.net中定义了一个用户类，它有几种方法，用于与数据库连接，我使用linq，在每种方法中我都必须使用:

hi experts,
i have a big question plz help me,i defined a user class in asp.net that it has several method ,for connect with database i use linq,in every method i have to use:

TestDatacontext db=new TestDatacontex();
...

在该课程的第一部分，我定义了:

at the first of this class i defined:

private static MyDataClassesDataContext _db;
        public static MyDataClassesDataContext Db
        {
            get
            {
                if (_db == null)
                {
                    _db = new MyDataClassesDataContext();
                }
                return (_db);
            }
        }

在我从该变量使用的每个方法中，并且我没有在方法中定义

and in every method i used from this variable and i dont define

TestDatacontext db=new TestDatacontex();

，它正确还是我必须在方法中定义db?
预先感谢您的回答.

in methods ,its correct or i must define db in methods?
Thanks in advance for an answer.

推荐答案

joonjooni，

您已经为entityframework实现了单例设计模式:

http://www.dofactory.com/Patterns/PatternSingleton.aspx [
例如，这个人反对它:
http://www.britishdeveloper.co.uk/2011/03/dont-use-singleton-datacontexts-entity.html [ ^ ]

这个家伙就是这样的:
http://cgeers.com/2009/02/21/entity-framework-objectcontext/ [ ^ ]

在我看来，有一个使用DataContext的单例模式是一个好主意.

希望对您有所帮助.

Hi joonjooni,

You have implemented singleton design pattern for entityframework :

http://www.dofactory.com/Patterns/PatternSingleton.aspx[^]

Its a controversy subject that people should use singleton design pattern for EF or not. so try to google for "entity framework singleton pattern"

for example this guy is against it :
http://www.britishdeveloper.co.uk/2011/03/dont-use-singleton-datacontexts-entity.html[^]

And this guy is for it :
http://cgeers.com/2009/02/21/entity-framework-objectcontext/[^]

In my opinion its a good idea to have a singleton pattern for working with DataContext.

Hope it helps.

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