正确使用“使用”数据文本语句 [英] Proper use of "Using" statement for datacontext
问题描述
使用（DataContext db = new DataContext）{
var xx = db.customers;
}
这是有道理的。但是，我不知道如何将这种做法纳入我的模型。
例如：我有一个接口（我们称之为客户），它由一个这样的存储库实现：
namespace模型
{
public class rCustomer：iCustomer
{
readonly DataContext db = new DataContext（）;
public customer getCustomer（Guid id）
{
return db.customers.SingleOrDefault（por => por.id == id）;
}
public iQueryable< customer> getTopCustomers（）
{
return db.customers.Take（10）;
}
// ************************************* ********
//更多使用db的方法，包括添加，更新，删除等。
// **************** ***************************
}
}
然后，为了利用使用，我需要将方法改为如下所示：
命名空间模型
{
public class rCustomer：iCustomer
{
public customer getCustomer（Guid id）
{
using（DataContext db = new DataContext（））{
return db.customers.SingleOrDefault（por => por.id == id）;
}
}
public iQueryable< customer> getTopCustomers（）
{
using（DataContext db = new DataContext（））{
return db.customers.Take（10）;
}
}
// **************************** *************
//更多使用db的方法
// ********************* **********************
}
}
我的问题是：使用使用的建议真的很好吗？请考虑这个变化将是一个主要的我有大约25个接口/存储库组合，每个都有大约20-25个方法，更不用说完成后需要重新测试一切。
有其他方式吗？
谢谢！
Edgar。
您可以实现一个数据库工厂，这将导致您的 DbContext被重用。
您可以实现如下：
DatabaseFactory类：
public class DatabaseFactory：Disposable，IDatabaseFactory
{
private YourEntities _dataContext;
public YourEntities Get（）
{
return _dataContext ?? （_dataContext = new YourEntities（））;
}
protected override void DisposeCore（）
{
if（_dataContext！= null）
_dataContext.Dispose（）;
}
}
存储库基类的摘录：
public abstract class Repository< T> ：IRepository< T>其中T：class
{
private YourEntities _dataContext;
private readonly IDbSet< T> _dbset;
protected Repository（IDatabaseFactory databaseFactory）
{
DatabaseFactory = databaseFactory;
_dbset = DataContext.Set< T>（）;
}
protected IDatabaseFactory DatabaseFactory
{
get;
私人集;
}
protected YourEntities DataContext
{
get {return _dataContext ?? （_dataContext = DatabaseFactory.Get（））;
}
您的表的存储库类：
public class ApplicationRepository：Repository< YourTable> IYourTableRepository
{
private YourEntities _dataContext;
保护新的IDatabaseFactory DatabaseFactory
{
get;
私人集;
}
public YourTableRepository（IDatabaseFactory databaseFactory）
：base（databaseFactory）
{
DatabaseFactory = databaseFactory;
}
保护新的YourEntities DataContext
{
get {return _dataContext？ （_dataContext = DatabaseFactory.Get（））; }
}
}
public interface IYourTableRepository：IRepository< YourTable>
{
}
}
这与AutoFac完美配合构造函数注入。
I’m using Linq to Entities and lately, I found that a lot of folks recommending wrapping the datacontext in a using statement like this:
Using(DataContext db = new DataContext) {
var xx = db.customers;
}
This makes sense. However, I’m not sure how to incorporate this practice in my model. For example: I have an interface (let’s call it customer) and it is implemented by a repository like this:
namespace Models
{
public class rCustomer : iCustomer
{
readonly DataContext db = new DataContext();
public customer getCustomer(Guid id)
{
return db.customers.SingleOrDefault(por => por.id == id);
}
public iQueryable<customer> getTopCustomers()
{
return db.customers.Take(10);
}
//*******************************************
//more methods using db, including add, update, delete, etc.
//*******************************************
}
}
Then, to take the advantage of using, I will need to change the methods to look like this:
namespace Models
{
public class rCustomer : iCustomer
{
public customer getCustomer(Guid id)
{
using(DataContext db = new DataContext()) {
return db.customers.SingleOrDefault(por => por.id == id);
}
}
public iQueryable<customer> getTopCustomers()
{
using(DataContext db = new DataContext()) {
return db.customers.Take(10);
}
}
//*******************************************
//more methods using db
//*******************************************
}
}
My question is: the recommendation of using "Using" is really that good? Please take in consideration that this change will be a major one, I have about 25 interfaces/repository combos, and each has about 20-25 methods, not to mention the need to re-test everything after finish. Is there other way?
Thanks!
Edgar.
You can implement a Database factory which will cause your DbContext is being reused.
You can achieve this as follows:
DatabaseFactory class:
public class DatabaseFactory : Disposable, IDatabaseFactory
{
private YourEntities _dataContext;
public YourEntities Get()
{
return _dataContext ?? (_dataContext = new YourEntities());
}
protected override void DisposeCore()
{
if (_dataContext != null)
_dataContext.Dispose();
}
}
Excerpt of the Repository base class:
public abstract class Repository<T> : IRepository<T> where T : class
{
private YourEntities _dataContext;
private readonly IDbSet<T> _dbset;
protected Repository(IDatabaseFactory databaseFactory)
{
DatabaseFactory = databaseFactory;
_dbset = DataContext.Set<T>();
}
protected IDatabaseFactory DatabaseFactory
{
get;
private set;
}
protected YourEntities DataContext
{
get { return _dataContext ?? (_dataContext = DatabaseFactory.Get()); }
}
Your table's repository class:
public class ApplicationRepository : Repository<YourTable>, IYourTableRepository
{
private YourEntities _dataContext;
protected new IDatabaseFactory DatabaseFactory
{
get;
private set;
}
public YourTableRepository(IDatabaseFactory databaseFactory)
: base(databaseFactory)
{
DatabaseFactory = databaseFactory;
}
protected new YourEntities DataContext
{
get { return _dataContext ?? (_dataContext = DatabaseFactory.Get()); }
}
}
public interface IYourTableRepository : IRepository<YourTable>
{
}
}
This works perfectly together with AutoFac constructor injection as well.
这篇关于正确使用“使用”数据文本语句的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
