ASP.NET MVC 4, la méthode «Websecurity.InitializedAbaseconnection» peut être appelée qu'une seule fois

Je développe une application Web de code de code dans Visual Studio 2012 Express.

J'utilise cette chaîne de connexion dans le web.config: p> xxx pré>

J'utilise SimpleMembership . P>

J'essaie de semer 1 administrateur de filtres / initialisiseimplememberthipattribute.cs: ... p>

using System;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Threading;
using System.Web.Mvc;
using WebMatrix.WebData;
using System.Web.Security;
using myapPMVC4.Models;

namespace myapPMVC4.Filters
{
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
    public sealed class InitializeSimpleMembershipAttribute : ActionFilterAttribute
    {
        private static SimpleMembershipInitializer _initializer;
        private static object _initializerLock = new object();
        private static bool _isInitialized;

        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
           LazyInitializer.EnsureInitialized(ref _initializer, ref _isInitialized, ref _initializerLock);
        }

        private class SimpleMembershipInitializer
        { 
            public SimpleMembershipInitializer()
            {
                Database.SetInitializer<UsersContext>(null);

                try
                {
                    using (var context = new UsersContext())
                    {
                        if (!context.Database.Exists())
                        {
                            // Create the SimpleMembership database without Entity Framework migration schema
                            ((IObjectContextAdapter)context).ObjectContext.CreateDatabase();
                        }
                    }

                    //WebSecurity.InitializeDatabaseConnection("DefaultConnection", "UserProfile", "UserId", "UserName", autoCreateTables: true);

                    if (!WebSecurity.Initialized)
                    {
                       WebSecurity.InitializeDatabaseConnection("myapPMVC4DBContext", "Users", "UserId", "Email", autoCreateTables: true);
                    }


                    // Create Admin user
                    if (!WebSecurity.ConfirmAccount("admin@myapp.com"))
                    {
                       //WebSecurity.CreateUserAndAccount("admin", "pass", new { email = "a@b.com" });
                       WebSecurity.CreateUserAndAccount("admin@myapp.com", "pass");
                    }

                    // Create admin role if not exist
                    if (!Roles.RoleExists("Administrator"))
                    {
                       Roles.CreateRole("Administrator");
                       Roles.AddUserToRole("admin@myapp.com", "Administrator");
                    }


                }
                catch (Exception ex)
                {
                    throw new InvalidOperationException("The ASP.NET Simple Membership database could not be initialized. For more information, please see http://go.microsoft.com/fwlink/?LinkId=256588", ex);
                }
            }
        }
    }
}