Question

I have an ASP.NET MVC 3 application and in my project I use ADO.NET Entity Data Model.

For access to data I use intermediate class (DataManager):

public class DataManager
{
    private static mrhomeEntities _dataContext;

    public DataManager()
    {
        _dataContext = new mrhomeEntities();
    }

    private OptionStorageRepository _optionStorageRepository;

    public OptionStorageRepository OptionStorage
    {
        get { return _optionStorageRepository ?? (_optionStorageRepository = new OptionStorageRepository(_dataContext)); }
    }
}

In OptionStorageRepository class I have 1 method that returns a list of options:

    public IQueryable<OptionStorage> List()
    {
        return _dataContext.OptionStorage;
    }

Such classes I have more than 15 (with this structure) to get and edit data in database.

Still I have my ControllerFabrick, where I pass a new object of DataManager class:

public class ControllerFabricFactory : DefaultControllerFactory 
{
    protected override IController GetControllerInstance(System.Web.Routing.RequestContext requestContext, Type controllerType)
    {
        return Activator.CreateInstance(controllerType, new DataManager()) as IController;
    }
}

Also I registered my controller fabrick in Global.asax like this:

    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();
        RegisterGlobalFilters(GlobalFilters.Filters);
        RegisterRoutes(RouteTable.Routes);
        ControllerBuilder.Current.SetControllerFactory(new ControllerFabricFactory());
    }

And in all Controllers I receive this parameter in constructor and using in my action methods:

public class HomeController : Controller
{
    private readonly DataManager dm;

    public HomeController(DataManager dm)
    {
        this.dm = dm;
    }
    [HttpGet]
    public ActionResult Main()
    {
        Page page = dm.Page.Details(mainPageName);

        PageNews pageNews = new PageNews();
        pageNews.page = page;
        pageNews.NewsList = dm.News.List(5);
        pageNews.PopularProject = dm.Project.GetPopularProject();

        if (pageNews.PopularProject != null)
        {
            var list = pageNews.PopularProject.ProjectPictures.Where(p => p.ProjectPictureTypes.Id == 1).ToList();
            if (list.Count > 0)
            {
                ViewData["img"] = list[0].ThumbPath;
            }
        }
        foreach (var item in dm.Page.List())
        {
            ViewData[item.Name] = item.ShortPageText;
        }
        ViewData["projects"] = dm.Project.GetMainPageProjects();
        ViewData["MainText"] = dm.Page.Details("maintext").PageText;
        return View(pageNews);
    }
}

And my question:

When I test my application in web browser I have strange errors, that contains information about connection to database or retrieving data, I have collection of my errors below:

• The connection was not closed. The connection’s current state is
  connecting.
• Invalid attempt to read when no data is present
• ExecuteReader requires an open and available Connection. The
  connection’s current state is open.
• New transaction is not allowed because there are other threads
  running in the session.
• An item with the same key has already been added.

Maybe I used wrong structure for get the data?

Answer 1

Per question:

Update: problem resolved, object DataContext was static (