Design of Service Layer and Repositories in Microsoft MVC

问题

I have the following problem - or rather, an urgent need for valuable advice - with Microsoft MVC. A certain action from the client leads to the creation of:

A remark in the table Remarks
An entry in the table for HourRegistrations
An entry in the changelog for Tickets

I use a service layer for business actions and repositories for CRUD actions. The problem is that I at times need to connect objects from different DataContexts so I suppose I use a flawed design. Recently we have started to remove all business logic from our controllers and repositories and this is one of the first things I run into.

Example:

BLogic.AddRemarks(Ticket t, ...)
{
  Remark r = _remarksRepository.Create();
  r.Ticket = t;
  _remarksRepository.Add(r);
  _remarksRepository.Save();
}

This triggers kBOOM since the Ticket is fetched in the controller using the repository. So Remark r and Ticket t do not share the same data context.

I can alter the signature of the method and provide an int TicketId, but that doesn't feel right. Besides, I then get similar problems further down the line.

My repositories are created at the constructor of the service class. Perhaps I must create them at the start of a method? Even then, I must often transfer Ids instead of the true objects.

回答1:

My suggestion is to use dependeny injection (or inversion of control - depends how would you like to call it). I use myself castle windor. Really simple to integrate with mvc.net. read more

When IoC is up and running create ContextManager. Somethig like this:

public class ContextManager : IContextManager
{
    private XContext context;

    public XContext GetContext()
    {
        return context ?? (context = XContext.Create());
    }
}

Set IContextManager lifestyle as perwebrequest and you got yourself context that you can access from repositories and services. and it's same per one request.

EDIT

You also have to create your own controllerFactory

then you can use your services and repositories like this:

public class MyController : Controller
{
    public ISomeService SomeService { get; set; }
    public IContextManager ContextManager { get; set; }

...

}

You dont have to create new instances for services and repositories and you can manage those objects lifestyle from configuration. Most reasonable would be singleton

来源：https://stackoverflow.com/questions/6072707/design-of-service-layer-and-repositories-in-microsoft-mvc

标签

asp.net-mvc

linq

design-patterns

repository