Asp.net mvc 具有实体框架和更新记录的MVC存储库模式_Asp.net Mvc_Entity Framework_Dependency Injection_Repository Pattern

Asp.net mvc 具有实体框架和更新记录的MVC存储库模式

asp.net-mvc entity-framework dependency-injection

Asp.net mvc 具有实体框架和更新记录的MVC存储库模式,asp.net-mvc,entity-framework,dependency-injection,repository-pattern,Asp.net Mvc,Entity Framework,Dependency Injection,Repository Pattern,我试图在MVC应用程序中使用EntityFramework的repository模式来更新记录，但是db.SaveChanges（）方法没有保存到数据库中。我没有收到任何错误，我可以逐步检查代码，看到传递了正确的变量，以及更新了记录变量根据我所阅读的内容，我认为我的问题在于我有两个数据库上下文实例（MyDBEntities）。问题可能是，创建MyDBEntities实例的my ReadRepository被注入到WriteRepository中，而WriteRepository也创建了一个实例

我试图在MVC应用程序中使用EntityFramework的repository模式来更新记录，但是db.SaveChanges（）方法没有保存到数据库中。我没有收到任何错误，我可以逐步检查代码，看到传递了正确的变量，以及更新了记录变量

根据我所阅读的内容，我认为我的问题在于我有两个数据库上下文实例（MyDBEntities）。问题可能是，创建MyDBEntities实例的my ReadRepository被注入到WriteRepository中，而WriteRepository也创建了一个实例MyDBEntities。我不确定如何将实体注入到存储库中（假设我需要这样做）

如果我尝试添加类似于

db.MyTable.Attach（记录）的内容

在

db.SaveChanges（）

之前，我将在下面得到这个错误，这使我认为我需要注入

MyDBEntities（）

一个实体对象不能被多个IEntityChangeTracker实例引用。

控制器

public class MyController : Controller
{
    private IWriteRepository _writeRepository;

    public MyController(IWriteRepository writeRepository)
    {
        _writeRepository = writeRepository;
    }

    [HttpPost]
    public ActionResult MyPostMethod(MyViewModel model)
    {
        try
        {
            //Send to the repository to edit a record
            writeRepository.EditRecord(model);

            return new HttpStatusCodeResult(HttpStatusCode.OK);
        }
        catch
        {
            throw new HttpException(500, "Internal Server Error");
        }            
    }
}

写入存储库

//The ReadRepository is injected into the WriteRepository to grab records from the database
public class WriteRepository : IWriteRepository
{
    private MyDBEntities db = new MyDBEntities();
    private IReadRepository _readRepository;

    public WriteRepository(IReadRepository readeadRepository)
    {
        _readRepository = readRepository;
    }        

    public void EditRecord(MyViewModel model)
    {
        //Get the specific record to be updated
        var record = readRepository.GetRecord(model.ID);

        //Update the data
        record.FirstName = model.Name;

        //This isn't saving
        db.SaveChanges();
    }
}

public class ReadRepository : IReadRepository
{
    private MyDBEntities db = new MyDBEntities();

    //Provides the record to the write repository to edit
    public MyTable GetRecord(int ID)
    {
        var record = (from t in db.MyTable
                      where t.ID == ID
                      select t).SingleOrDefault();

        return record;
    }
}

读取存储库

//The ReadRepository is injected into the WriteRepository to grab records from the database
public class WriteRepository : IWriteRepository
{
    private MyDBEntities db = new MyDBEntities();
    private IReadRepository _readRepository;

    public WriteRepository(IReadRepository readeadRepository)
    {
        _readRepository = readRepository;
    }        

    public void EditRecord(MyViewModel model)
    {
        //Get the specific record to be updated
        var record = readRepository.GetRecord(model.ID);

        //Update the data
        record.FirstName = model.Name;

        //This isn't saving
        db.SaveChanges();
    }
}

public class ReadRepository : IReadRepository
{
    private MyDBEntities db = new MyDBEntities();

    //Provides the record to the write repository to edit
    public MyTable GetRecord(int ID)
    {
        var record = (from t in db.MyTable
                      where t.ID == ID
                      select t).SingleOrDefault();

        return record;
    }
}

从您的MyController代码来看，您似乎已经在使用控制反转框架，因此请按如下方式更新您的ReadRepository和WriteRepository类：

ReadRepository

public class ReadRepository : IReadRepository
{
    private MyDBEntities db;

    public ReadRepository(MyDBEntities myDbEntities) 
    {
        db = myDbEntities;
    }

    //Provides the record to the write repository to edit
    public MyTable GetRecord(int ID)
    {
        var record = (from t in db.MyTable
                      where t.ID == ID
                      select t).SingleOrDefault();

        return record;
    }
}

public class WriteRepository : IWriteRepository
{
    private MyDBEntities db;
    private IReadRepository _readRepository;

    public WriteRepository(MyDBEntities myDbEntities, IReadRepository readeadRepository)
    {
        db = myDbEntities;
        _readRepository = readRepository;
    }        

    public void EditRecord(MyViewModel model)
    {
        //Get the specific record to be updated
        var record = readRepository.GetRecord(model.ID);

        //Update the data
        record.FirstName = model.Name;

        //This isn't saving
        db.SaveChanges();
    }
}

WriteRepository

public class ReadRepository : IReadRepository
{
    private MyDBEntities db;

    public ReadRepository(MyDBEntities myDbEntities) 
    {
        db = myDbEntities;
    }

    //Provides the record to the write repository to edit
    public MyTable GetRecord(int ID)
    {
        var record = (from t in db.MyTable
                      where t.ID == ID
                      select t).SingleOrDefault();

        return record;
    }
}

public class WriteRepository : IWriteRepository
{
    private MyDBEntities db;
    private IReadRepository _readRepository;

    public WriteRepository(MyDBEntities myDbEntities, IReadRepository readeadRepository)
    {
        db = myDbEntities;
        _readRepository = readRepository;
    }        

    public void EditRecord(MyViewModel model)
    {
        //Get the specific record to be updated
        var record = readRepository.GetRecord(model.ID);

        //Update the data
        record.FirstName = model.Name;

        //This isn't saving
        db.SaveChanges();
    }
}

您的ReadRepository和WriteRepository都依赖于MyDBEntities的实例来执行工作，因此，您应该在这些类的构造函数中指定该依赖项，并让您的控制反转框架来处理创建它，而不是自己创建一个新的MyDBEntities实例
确保在控制反转框架的注册中，您正在将您的MyDBEntities实例注册为作用域或每个请求，而不是临时的。您希望确保在每次请求时，您的ReadRepository和WriteRepository都会被注入与MyDBEntities类相同的实例，而不是像现在这样的两个独立实例
按如下方式更新Unity配置：
UnityConfig.cs
在每个请求范围内向Unity注册您的MyDBEntities类

public class UnityConfig { // ... other methods ... public static void RegisterTypes(IUnityContainer container) { // ... other registrations ... container.RegisterType<IReadRepository, ReadRepository>(); container.RegisterType<IWriteRepository, WriteRepository>(); container.RegisterType<MyDBEntities>(new PerRequestLifetimeManager()); // ... other registrations ... } }

从您的MyController代码来看，您似乎已经在使用控制反转框架，因此请按如下方式更新您的ReadRepository和WriteRepository类：
ReadRepository

public class ReadRepository : IReadRepository { private MyDBEntities db; public ReadRepository(MyDBEntities myDbEntities) { db = myDbEntities; } //Provides the record to the write repository to edit public MyTable GetRecord(int ID) { var record = (from t in db.MyTable where t.ID == ID select t).SingleOrDefault(); return record; } }

public class WriteRepository : IWriteRepository { private MyDBEntities db; private IReadRepository _readRepository; public WriteRepository(MyDBEntities myDbEntities, IReadRepository readeadRepository) { db = myDbEntities; _readRepository = readRepository; } public void EditRecord(MyViewModel model) { //Get the specific record to be updated var record = readRepository.GetRecord(model.ID); //Update the data record.FirstName = model.Name; //This isn't saving db.SaveChanges(); } }
WriteRepository

public class ReadRepository : IReadRepository { private MyDBEntities db; public ReadRepository(MyDBEntities myDbEntities) { db = myDbEntities; } //Provides the record to the write repository to edit public MyTable GetRecord(int ID) { var record = (from t in db.MyTable where t.ID == ID select t).SingleOrDefault(); return record; } }

public class WriteRepository : IWriteRepository { private MyDBEntities db; private IReadRepository _readRepository; public WriteRepository(MyDBEntities myDbEntities, IReadRepository readeadRepository) { db = myDbEntities; _readRepository = readRepository; } public void EditRecord(MyViewModel model) { //Get the specific record to be updated var record = readRepository.GetRecord(model.ID); //Update the data record.FirstName = model.Name; //This isn't saving db.SaveChanges(); } }
您的ReadRepository和WriteRepository都依赖于MyDBEntities的实例来执行工作，因此，您应该在这些类的构造函数中指定该依赖项，并让您的控制反转框架来处理创建它，而不是自己创建一个新的MyDBEntities实例
确保在控制反转框架的注册中，您正在将您的MyDBEntities实例注册为作用域或每个请求，而不是临时的。您希望确保在每次请求时，您的ReadRepository和WriteRepository都会被注入与MyDBEntities类相同的实例，而不是像现在这样的两个独立实例
按如下方式更新Unity配置：
UnityConfig.cs
在每个请求范围内向Unity注册您的MyDBEntities类

public class UnityConfig { // ... other methods ... public static void RegisterTypes(IUnityContainer container) { // ... other registrations ... container.RegisterType<IReadRepository, ReadRepository>(); container.RegisterType<IWriteRepository, WriteRepository>(); container.RegisterType<MyDBEntities>(new PerRequestLifetimeManager()); // ... other registrations ... } }

可能是我读过的那一部分的重复，但是我正在寻找关于如何在存储库之外创建数据库上下文的帮助。可能是我读过的那一部分的重复，但是我正在寻找关于如何在存储库之外创建数据库上下文的帮助。回答很好。你正按照我的要求行事。实际上，我在使用Unity作为框架，但在最后一部分中，我不知道注册什么或如何注册实体。好的，我用Unity注册更新了我的答案。谢谢更新。如果一切正常，我会试试这个，并把它作为答案。我们能得到一些反馈吗，@madvora？请标记为已回答或添加其他后续评论。僵尸问题伤害了所有人。回答得很好。你正按照我的要求行事。实际上，我在使用Unity作为框架，但在最后一部分中，我不知道注册什么或如何注册实体。好的，我用Unity注册更新了我的答案。谢谢更新。如果一切正常，我会试试这个，并把它作为答案。我们能得到一些反馈吗，@madvora？请标记为已回答或添加其他后续评论。僵尸问题伤害了所有人。