Question

我尝试使用错误模块（Application_Error），HttpModuleMagic.MVC3，Ninject.MVC3，EF 4.1进行自定义错误处理（http://perspectivespace.com/100497697）。不幸的是，当我想将错误记录到数据库时，它会给出以下错误消息： “由于已经处理了DbContext，因此无法完成操作。”

有人可以帮帮我吗？

public class ErrorHandlerHttpModule : IHttpModule
{
    private const string ErrorControllerRouteName = "Error";
    private IErrorRepository errorRepo;
    private IUserRepository userRepo;

  //  private IUserRepository UserRepository;

    public ErrorHandlerHttpModule(IErrorRepository er, IUserRepository ur)
    {
        errorRepo = er;
        userRepo = ur;
    }

    public void Dispose()
    {
    }

    public void Init(HttpApplication context)
    {
        context.Error += Application_Error;
    }

    private void Application_Error(object sender, EventArgs e)
    {
        // Get the last error.

        var exception = HttpContext.Current.Server.GetLastError();
    ...

    error.User = userRepo.GetUserByName(name);

    ...

在NinjectWebCommon.cs中：

    private static void RegisterServices(IKernel kernel)
    {
        kernel.Bind<IErrorRepository>().To<ErrorRepository>().InRequestScope();
        kernel.Bind<IUserRepository>().To<UserRepository>().InRequestScope();

        kernel.Bind<IDatabaseFactory>().To<DatabaseFactory>().InRequestScope();

        kernel.Bind<IDisposable>().To<Disposable>().InRequestScope();
        kernel.Bind<IHttpModule>().To<ErrorHandlerHttpModule>();
    }

...和UserRepository类：

public class UserRepository : RepositoryBase<User>, IUserRepository
{
    public UserRepository(IDatabaseFactory databaseFactory)
    : base(databaseFactory)
    {
    } 

    public User GetUserByName(string name)
    {
        User us = null;
        try
        {
            us = dataContext.Users.Where(u => u.UserName.Equals(name)).FirstOrDefault() as User;
        }
        catch (Exception ex)
        {

        }
        return us;
    }
}

RepositoryBase：

public abstract class RepositoryBase<T> where T : class
{
    protected TestContext dataContext;
    private readonly IDbSet<T> dbset;
    protected RepositoryBase(IDatabaseFactory databaseFactory)
    {
        DatabaseFactory = databaseFactory;
        dbset = DataContext.Set<T>();
    }

    protected IDatabaseFactory DatabaseFactory
    {
        get;
        private set;
    }

    protected TestContext DataContext
    {
        get { return dataContext ?? (dataContext = DatabaseFactory.Get()); }
    }
    ...

和DatabaseFactory类：

public class DatabaseFactory : Disposable, IDatabaseFactory
{
    private TestContext dataContext;

    public TestContext Get()
    {
        return dataContext ?? (dataContext = new TestContext());
    }

    protected override void DisposeCore()
    {
        if (dataContext != null)
            dataContext.Dispose();
    }
}

此行潜水错误：

dataContext.Users.Where(u => u.UserName.Equals(name)).FirstOrDefault() as User;

我尝试按照这篇文章： http://weblogs.asp.net/shijuvarghese/archive/2011/01/06/developing-web-apps-using-asp-net-mvc-3-razor-and-ef-code-first-part-1.aspx

感谢您的回答。

Answer 1

protected override void DisposeCore()
{
   if (dataContext != null)
   {
      dataContext.Dispose();
      dataContext = null;
   }
}

Answer 2

原因是您的LINQ查询被延迟，换句话说，它不会在您的＆＃34; UserRepository＆＃34;中运行。但只在调用代码中。因此DBContext在执行时已经被处理掉了。您可以通过更改

强制它立即执行

us = dataContext.Users.Where(u => u.UserName.Equals(name)).FirstOrDefault() as User

到

us = dataContext.Users.Where(u => u.UserName.Equals(name)).ToList().FirstOrDefault() as User

由于已经处理了DbContext，因此无法完成操作

2 个答案: