How can I prevent EF “The context cannot be used while the model is being created” errors?

I finally figured out the true cause of this, at least for me.

The issue was that I was retrieving a DbContext from Windsor in my custom Asp.Net Membership provider. This caused an issue because the membership provider has a lifespan of the whole application, while all other retrieval calls for the db context were new db contexts for the specific web requests. This meant that two database contexts were “spinning up” at the same time and thus this error was thrown.

This also caused a lot of hard to debug entity caching issues as well, so anyone who uses EF in their membership provider needs to be real careful about their context lifetime.

Edit: In response to DotNetWise, I solved this by forcing my custom membership provider to always use an EF connection from Windsor by storing the Windsor connection factory in my constructor, then always retrieving my EF data context from the factory at that point.

For example:

public class CustomMembershipProvider : MembershipProvider
{
    private IServiceFactory _serviceFactory;

    public CustomMembershipProvider() : this(null) { }

    public CustomMembershipProvider(IServiceFactory factory)
    {
        // IF no factory was provided, we need to get one from the bootstrapper
        if (factory == null)
            _serviceFactory = new WindsorServiceFactory(Bootstrapper.WindsorContainer);
        else
            _serviceFactory = factory;
    }

    public override string ResetPassword(string email, string answer)
    {
        var unitOfWork = GetUnitOfWork();
        return new ResetUserPasswordCommand(unitOfWork).WithUserEmail(email).Execute();
    }

    private IUnitOfWork GetUnitOfWork()
    {
       return _serviceFactory.GetService<IUnitOfWork>();
    }
}

The idea being that any action the membership provider performs gets the UnitOfWork class from Windsor, and uses that to perform the action (in this case my UnitOfWork class is a repository holder to wrap up my EF data context)