Shopping cart session specific to instance - asp.net

Strange - Session - Inproc - mode use cookies name asp_net session id, timeout 20 , is shared across clients, not sure !!! session should be unique for each client, but its been shared across clients !!
In my asp.net application, the shopping cart session has been shared across the requests, not sure how happened,it should be different specific to the request , each request in IIS should have each session, but all the requests in IIS is been shared by this session`public class PODCart
{
#region Properties
public List<PODCartItem> Items { get; private set; }
#endregion
#region Singleton Implementation
public static readonly PODCart Instance;
static PODCart()
{
if (HttpContext.Current.Session["C"] == null)
{
Instance = new PODCart();
Instance.Items = new List<PODCartItem>();
HttpContext.Current.Session["C"] = Instance;
}
else
Instance = (PODCart)HttpContext.Current.Session["C"];
}
protected PODCart() { }
}`
Really need to know the fix as quick as possible, though the singleton implementation is done.

You have a singleton class defined and you are assigning it to every single session. Of course it's going to use the same one.
It really looks like PODCart shouldn't be a singleton.

Related

Using Unity Dependency Injection in Multi-User Web Application: Second User to Log In Causes First User To See Second User's Data

I'm trying to implement a web application using ASP.NET MVC and the Microsoft Unity DI framework. The application needs to support multiple user sessions at the same time, each of them with their own connection to a separate database (but all users using the same DbContext; the database schemas are identical, it's just the data that is different).
Upon a user's log-in, I register the necessary type mappings to the application's Unity container, using a session-based lifetime manager that I found in another question here.
My container is initialized like this:
// Global.asax.cs
public static UnityContainer CurrentUnityContainer { get; set; }
protected void Application_Start()
{
// ...other code...
CurrentUnityContainer = UnityConfig.Initialize();
// misc services - nothing data access related, apart from the fact that they all depend on IRepository<ClientContext>
UnityConfig.RegisterComponents(CurrentUnityContainer);
}
// UnityConfig.cs
public static UnityContainer Initialize()
{
UnityContainer container = new UnityContainer();
DependencyResolver.SetResolver(new UnityDependencyResolver(container));
GlobalConfiguration.Configuration.DependencyResolver = new Unity.WebApi.UnityDependencyResolver(container);
return container;
}
This is the code that's called upon logging in:
// UserController.cs
UnityConfig.RegisterUserDataAccess(MvcApplication.CurrentUnityContainer, UserData.Get(model.AzureUID).CurrentDatabase);
// UnityConfig.cs
public static void RegisterUserDataAccess(IUnityContainer container, string databaseName)
{
container.AddExtension(new DataAccessDependencies(databaseName));
}
// DataAccessDependencies.cs
public class DataAccessDependencies : UnityContainerExtension
{
private readonly string _databaseName;
public DataAccessDependencies(string databaseName)
{
_databaseName = databaseName;
}
protected override void Initialize()
{
IConfigurationBuilder configurationBuilder = Container.Resolve<IConfigurationBuilder>();
Container.RegisterType<ClientContext>(new SessionLifetimeManager(), new InjectionConstructor(configurationBuilder.GetConnectionString(_databaseName)));
Container.RegisterType<IRepository<ClientContext>, RepositoryService<ClientContext>>(new SessionLifetimeManager());
}
}
// SessionLifetimeManager.cs
public class SessionLifetimeManager : LifetimeManager
{
private readonly string _key = Guid.NewGuid().ToString();
public override void RemoveValue(ILifetimeContainer container = null)
{
HttpContext.Current.Session.Remove(_key);
}
public override void SetValue(object newValue, ILifetimeContainer container = null)
{
HttpContext.Current.Session[_key] = newValue;
}
public override object GetValue(ILifetimeContainer container = null)
{
return HttpContext.Current.Session[_key];
}
protected override LifetimeManager OnCreateLifetimeManager()
{
return new SessionLifetimeManager();
}
}
This works fine as long as only one user is logged in at a time. The data is fetched properly, the dashboards work as expected, and everything's just peachy keen.
Then, as soon as a second user logs in, disaster strikes.
The last user to have prompted a call to RegisterUserDataAccess seems to always have "priority"; their data is displayed on the dashboard, and nothing else. Whether this is initiated by a log-in, or through a database access selection in my web application that calls the same method to re-route the user's connection to another database they have permission to access, the last one to draw always imposes their data on all other users of the web application. If I understand correctly, this is a problem the SessionLifetimeManager was supposed to solve - unfortunately, I really can't seem to get it to work.
I sincerely doubt that a simple and common use-case like this - multiple users logged into an MVC application who each are supposed to access their own, separate data - is beyond the abilities of Unity, so obviously, I must be doing something very wrong here. Having spent most of my day searching through depths of the internet I wasn't even sure truly existed, I must, unfortunately, now realize that I am at a total and utter loss here.
Has anyone dealt with this issue before? Has anyone dealt with this use-case before, and if yes, can anyone tell me how to change my approach to make this a little less headache-inducing? I am utterly desperate at this point and am considering rewriting my entire data access methodology just to make it work - not the healthiest mindset for clean and maintainable code.
Many thanks.
the issue seems to originate from your registration call, when registering the same type multiple times with unity, the last registration call wins, in this case, that will be data access object for whoever user logs-in last. Unity will take that as the default registration, and will create instances that have the connection to that user's database.
The SessionLifetimeManager is there to make sure you get only one instance of the objects you resolve under one session.
One option to solve this is to use named registration syntax to register the data-access types under a key that maps to the logged-in user (could be the database name), and on the resolve side, retrieve this user key, and use it resolve the corresponding data access implementation for the user
Thank you, Mohammed. Your answer has put me on the right track - I ended up finally solving this using a RepositoryFactory which is instantiated in an InjectionFactory during registration and returns a repository that always wraps around a ClientContext pointing to the currently logged on user's currently selected database.
// DataAccessDependencies.cs
protected override void Initialize()
{
IConfigurationBuilder configurationBuilder = Container.Resolve<IConfigurationBuilder>();
Container.RegisterType<IRepository<ClientContext>>(new InjectionFactory(c => {
ClientRepositoryFactory repositoryFactory = new ClientRepositoryFactory(configurationBuilder);
return repositoryFactory.GetRepository();
}));
}
// ClientRepositoryFactory.cs
public class ClientRepositoryFactory : IRepositoryFactory<RepositoryService<ClientContext>>
{
private readonly IConfigurationBuilder _configurationBuilder;
public ClientRepositoryFactory(IConfigurationBuilder configurationBuilder)
{
_configurationBuilder = configurationBuilder;
}
public RepositoryService<ClientContext> GetRepository()
{
var connectionString = _configurationBuilder.GetConnectionString(UserData.Current.CurrentPermission);
ClientContext ctx = new ClientContext(connectionString);
RepositoryService<ClientContext> repository = new RepositoryService<ClientContext>(ctx);
return repository;
}
}
// UserData.cs (multiton-singleton-hybrid)
public static UserData Current
{
get
{
var currentAADUID = (string)(HttpContext.Current.Session["currentAADUID"]);
return Get(currentAADUID);
}
}
public static UserData Get(string AADUID)
{
UserData instance;
lock(_instances)
{
if(!_instances.TryGetValue(AADUID, out instance))
{
throw new UserDataNotInitializedException();
}
}
return instance;
}
public static UserData Current
{
get
{
var currentAADUID = (string)(HttpContext.Current.Session["currentAADUID"]);
return Get(currentAADUID);
}
}
public static UserData Get(string AADUID)
{
UserData instance;
lock(_instances)
{
if(!_instances.TryGetValue(AADUID, out instance))
{
throw new UserDataNotInitializedException();
}
}
return instance;
}

MVC Custom Membership and Role Provider context lifetime issue

I'm having problems with custom membership within MVC 4 I keep getting a context lifetime related error when I do a ajax call to get a partial result from the server(controller), the error is always {"The provider has been closed"} or {"There is already an open DataReader associated with this Command which must be closed first."} the error always lands within the custom RoleProvider.
I will try to explain the current setup im using.
I have inherited from the Membership and RoleProvier and overridden all the methods like so
public class CustomRoleProvider : RoleProvider
{
private IAccountService _accountService;
public CustomRoleProvider()
{
_accountService = new AccountService();
}
public override string[] GetRolesForUser(string username)
{
return _accountService.GetRolesForUser(username);
}
}
The Membership provider is implemented in the same way the IAccountService above is the service layer that deals with all user accounts & roles all the service layer classes implement a base service class called ServiceBase that creates the DB context
public class ServiceBase
{
protected Context Context;
protected ServiceBase() : this("Context") {}
protected ServiceBase(string dbName)
{
IDatabaseInitializer<Context> initializer = new DbInitialiser();
Database.SetInitializer(initializer);
Context = new Context(dbName);
}
}
The Controller that has the ajax to made to it
[Authorize(Roles = "Administrator,Supplier")]
public class AuctionController : Controller
{
private IAuctionService _service;
public AuctionController()
{
_service = new AuctionService();
}
public AuctionController(IAuctionService service)
{
_service = service;
}
[CacheControl(HttpCacheability.NoCache), HttpGet]
public ActionResult RefreshAuctionTimes(int auctionId)
{
return PartialView("_AuctionTimer", BusinessLogic.Map.ConvertAuction(_service.GetAuction (auctionId)));
}
}
The problem only started when I added the [Authorize(Roles = "Administrator,Supplier")] attribute to the controller that handled the ajax call, I know this is the lifetime of the DbContext being for the life of the app and the controllers service layer being destroyed and recreated on every post but I'm not sure of the best way to handle this, I have used this setup before but with DI and Windsor and never had this problem as the IOC was controlling the context.
Would it be best to create the providers its own DB context or is the conflict between the 2 providers and really they need to share the same db context?
Any help would be great thanks
The problem is exactly what you're suspecting. Is due to the fact that you're creating a single instance of the DbContext and therefore you're having connection issues. If you use it with an IOC/DI schema, you're going to fix it. The other option is to manually handle the connections.
An example of how to do this using Ninject as IOC container is here
They need to share the same context in order for the problem to stop.
I would suggest you create your service layer class on each call to GetRolesForUser:
public override string[] GetRolesForUser(string username)
{
return new AccountService().GetRolesForUser(username);
}

asp.net custom role provider nhibernate error

HI,
I am implementing a custom role provider in my nhibernate application
I have a repository that I call whenever I want to access the nhibernate session.
So when my role provider initializes itself
public override void Initialize(string name, System.Collections.Specialized.NameValueCollection config) {
base.Initialize(name, config);
Repository = new Repository();
}
Then I override
public override string[] GetRolesForUser(string username) {
var users = Repository.QueryAll<Users>();
//I then filter and so on
}
But when this function is called I always get an error that the NHibernate session is closed.
I debugged the nhibernate source code and it turns out that the session here has a different guid that the session in my controllers(I am using ASP.NET MVC also).
And this particular session is closed by the time I get here.
I don't know who closes it. I know it is started when the application starts and only then.
Does anyone have any idea what I am doing wrong?
I want to still use Nhibernate in this provider but not get the error any more.
Thank you
I had what appears to be the exact same problem. Don't forget that Role and Membership providers are only instantiated once and exist for the lifetime of the application. If you're using a Session per Web request pattern, the ISession will be closed after the first request and then any reference to an ISession internal to the provider will likely be null for subsequent requests.
You can get around this by injecting a reference to the ISessionFactory and calling GetCurrentSession, instead of directly holding a reference to an ISession.
This is how I evetually fixed it.
in my repository class I had this:
public Repository()
{
this.Session = SessionManager.GetCurrentSession();
}
I deleted the constructor entirely
I put in this instead:
private ISession _session;
protected ISession Session
{
get
{
if (_session == null)
{
_session = SessionManager.GetCurrentSession();
}
return _session;
}
}

Managing NHibernate sessions for a multi-tenant ASP.NET application

I have an existing multi-tenant ASP.NET application where all users authenticate against a single SQL Server database. This database also contains several other settings type data that is used within the application. Each client after authentication, utilizes their own SQL Server database for data storage, for isolation purposes. Essentially all of the client database are identical and reside on the same server, but reside on one or more servers as well.
The application is currently written in asp.net 2.5 framework and utilizes the Microsoft Practices Enterprise Library for DAL, and we are looking to migrate to 4.0 and implement NHibernate to replace the MPEL.
I have implemented a solution already using NHibernate and the 4.0 framework, so I am familiar with the concepts. I found the resources for my current session manager here as a matter of fact. But that application only had a single database, so not much too it. The implementation is essentially what you see here:
http://www.lostechies.com/blogs/nelson_montalvo/archive/2007/03/30/simple-nhibernate-example-part-4-session-management.aspx
The other solutions that I have seen suggest multiple config entries and/or files to manage this, but that is not desirable, since we may add new clients frequently and all of the connection information is already maintained in the authentication database.
Does anyone have any suggestions on how I might be able to pass in the client's connection string to a session manager?
The following is my current session manager class, which is based on the article mentioned above.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.Remoting.Messaging;
using System.Web;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Cache;
using singlepoint.timeclock.domain;
namespace singlepoint.timeclock.repositories
{
/// <summary>
/// Handles creation and management of sessions and transactions. It is a singleton because
/// building the initial session factory is very expensive. Inspiration for this class came
/// from Chapter 8 of Hibernate in Action by Bauer and King. Although it is a sealed singleton
/// you can use TypeMock (http://www.typemock.com) for more flexible testing.
/// </summary>
public sealed class nHibernateSessionManager
{
private ISessionFactory idadSessionFactory;
private ISessionFactory clientSessionFactory;
private string _client;
#region Thread-safe, lazy Singleton
// lazy initialisation, therefore initialised to null
private static nHibernateSessionManager instance = null;
/// <summary>
/// This is a thread-safe, lazy singleton. See http://www.yoda.arachsys.com/csharp/singleton.html
/// for more details about its implementation.
/// </summary>
public static nHibernateSessionManager Instance
{
get { return GetInstance(); }
}
public static nHibernateSessionManager GetInstance()
{
// lazy init.
if (instance == null)
instance = new nHibernateSessionManager();
return instance;
} // GetInstance
/// <summary>
/// Initializes the NHibernate session factory upon instantiation.
/// </summary>
private nHibernateSessionManager()
{
InitSessionFactory();
}
/// <summary>
/// Initializes the NHibernate session factory upon instantiation.
/// </summary>
private nHibernateSessionManager(string client)
{
InitSessionFactory();
InitClientSessionFactory(client);
}
/// <summary>
/// Assists with ensuring thread-safe, lazy singleton
/// </summary>
private class Nested
{
static Nested()
{
}
internal static readonly nHibernateSessionManager nHibernatenHibernateSessionManager = new nHibernateSessionManager();
}
#endregion
private void InitSessionFactory()
{
var configuration = new Configuration();
configuration.Configure(System.Configuration.ConfigurationManager.AppSettings["IDAD_HBM"]);
configuration.AddAssembly(typeof(enterprise).Assembly);
idadSessionFactory = configuration.BuildSessionFactory();
}
private void InitClientSessionFactory(string client)
{
var configuration = new Configuration();
configuration.Configure(System.Configuration.ConfigurationManager.AppSettings["Client_IDAD_HBM"]);
configuration.SetProperty("connection.connection_string", client);
configuration.AddAssembly(typeof(enterprise).Assembly);
clientSessionFactory = configuration.BuildSessionFactory();
}
/// <summary>
/// Allows you to register an interceptor on a new session. This may not be called if there is already
/// an open session attached to the HttpContext. If you have an interceptor to be used, modify
/// the HttpModule to call this before calling BeginTransaction().
/// </summary>
public void RegisterInterceptor(IInterceptor interceptor)
{
ISession session = ThreadSession;
if (session != null && session.IsOpen)
{
throw new CacheException("You cannot register an interceptor once a session has already been opened");
}
GetSession(interceptor);
}
public ISession GetSession()
{
return GetSession(null);
}
/// <summary>
/// Gets a session with or without an interceptor. This method is not called directly; instead,
/// it gets invoked from other public methods.
/// </summary>
private ISession GetSession(IInterceptor interceptor)
{
ISession session = ThreadSession;
if (session == null)
{
if (interceptor != null)
{
session = idadSessionFactory.OpenSession(interceptor);
}
else
{
session = idadSessionFactory.OpenSession();
}
ThreadSession = session;
}
return session;
}
public void CloseSession()
{
ISession session = ThreadSession;
ThreadSession = null;
if (session != null && session.IsOpen)
{
session.Close();
}
}
public void BeginTransaction()
{
ITransaction transaction = ThreadTransaction;
if (transaction == null)
{
transaction = GetSession().BeginTransaction();
ThreadTransaction = transaction;
}
}
public void CommitTransaction()
{
ITransaction transaction = ThreadTransaction;
try
{
if (transaction != null && !transaction.WasCommitted && !transaction.WasRolledBack)
{
transaction.Commit();
ThreadTransaction = null;
}
}
catch (HibernateException ex)
{
RollbackTransaction();
throw ex;
}
}
public void RollbackTransaction()
{
ITransaction transaction = ThreadTransaction;
try
{
ThreadTransaction = null;
if (transaction != null && !transaction.WasCommitted && !transaction.WasRolledBack)
{
transaction.Rollback();
}
}
catch (HibernateException ex)
{
throw ex;
}
finally
{
CloseSession();
}
}
/// <summary>
/// If within a web context, this uses <see cref="HttpContext" /> instead of the WinForms
/// specific <see cref="CallContext" />. Discussion concerning this found at
/// http://forum.springframework.net/showthread.php?t=572.
/// </summary>
private ITransaction ThreadTransaction
{
get
{
if (IsInWebContext())
{
return (ITransaction)HttpContext.Current.Items[TRANSACTION_KEY];
}
else
{
return (ITransaction)CallContext.GetData(TRANSACTION_KEY);
}
}
set
{
if (IsInWebContext())
{
HttpContext.Current.Items[TRANSACTION_KEY] = value;
}
else
{
CallContext.SetData(TRANSACTION_KEY, value);
}
}
}
/// <summary>
/// If within a web context, this uses <see cref="HttpContext" /> instead of the WinForms
/// specific <see cref="CallContext" />. Discussion concerning this found at
/// http://forum.springframework.net/showthread.php?t=572.
/// </summary>
private ISession ThreadSession
{
get
{
if (IsInWebContext())
{
return (ISession)HttpContext.Current.Items[SESSION_KEY];
}
else
{
return (ISession)CallContext.GetData(SESSION_KEY);
}
}
set
{
if (IsInWebContext())
{
HttpContext.Current.Items[SESSION_KEY] = value;
}
else
{
CallContext.SetData(SESSION_KEY, value);
}
}
}
private static bool IsInWebContext()
{
return HttpContext.Current != null;
}
private const string TRANSACTION_KEY = "CONTEXT_TRANSACTION";
private const string SESSION_KEY = "CONTEXT_SESSION";
[Obsolete("only until we can fix the session issue globally")]
internal ISession OpenSession()
{
return idadSessionFactory.OpenSession();
}
}
}
This is being called from a repository class like so:
public string getByName(string name)
{
return getByName(nHibernateSessionManager.Instance.GetSession(), name);
}
What I would really like to be able to do is the following:
public string getByName(string name, string clientConnectionString)
{
return getByName(nHibernateSessionManager.Instance.GetSession(clientConnectionString), name);
}
But I am having trouble modifying my existing session manager to accomodate this.
You appear to be asking to swap a connection for a given session. Or rather that is certainly what the code you have written is asking - "return a session identified by the name parameter, and it should also now use the connection string provided by this method."
That is not possible. NHibernate builds a session (and actually really a session factory) per connection and once built the factory and session are immutable. You cannot change connections for an existing session.
I got the impression that your application involves mostly in initial connection string that is the moving target, but after that your "real" session is on a single database. If that is the case, NHibernate can easily do this. If that is not the case, well, some things NHibernate is just not that well suited for. Maybe understanding a little more about the basis NHibernate operates on is helpful either way?
One of my genuine criticisms of NHibernate is that you have a somewhat arcane use of terminology and the well known unhelpful nature of it's exception messages. These coupled with the fact that what it is doing is in reality mechanically complicated tends to really obscure that there is a relatively simple and technically sound underlying model.
In this case, if you think about it this business of an immutable session makes a lot of sense. NHibernate connects to a database, but it also maintains objects in the session so they can be persisted back to that database at a later time. NHibernate does not support changing connections per session because there may already be other objects in the session and if you change connections their persistence is no longer assured.
Now, what you can do is create a factory/session per database for multiple databases and access them in one application, but objects still belong to their own session. You can even move objects to a new session with a different connection. In this case you have what would logically be a "replication" scenario. NHibernate supports this but you have to do most of the work. This also makes sense - they really cannot give you that as stable out of the box functionality, you have to manage a process like that on your own.
You can also build code to do exactly what you are asking. But think about what that is. Make a session, not per database, but only for this specific instance of this specific repository. I am thinking that is most likely not really what you want. But that is exactly what the semantics of your request are saying to do. Your existing class, On the other hand, was built on different semantics which are more typically what people want - "Build a session for this particular connection definition, i.e this database."
A real need to inject a connection string at the repository level implies that now not only is the database a moving target, but at the actual table level the target also moves. If that is the case, NHibernate is possibly not a good option. If that is not the case, you may be trying to mix programming paradigms. NHiberate imposes a few what I would call "assumptions" rather than any sort of real "limitations" and in return you don't have to write a bunch of code that would allow you a finer grain of control because often you really don't need that additional control.
Sorry if this is no longer a direct answer to your question, hopefully it is helpful somehow.
Original Answer:
Sure, since the connection info is in the authentication database this is easy.
1) Configure NHibernate in the "usual" fashion and point the config at the authentication database. Get the db connection for the user, and then close that session and session factory. You are done with that one now.
2) Create a new session etc this time in code instead of a config file.
class MyNewSession
{
private ISession _session;
private ISessionFactory _factory;
public void InitializeSession()
{
NHibernate.Cfg.Configuration config = new NHibernate.Cfg.Configuration();
config.Properties.Clear();
IDictionary props = new Hashtable();
// Configure properties as needed, this is pretty minimal standard config here.
// Can read in properties from your own xml file or whatever.
// Just shown hardcoded here.
props["proxyfactory.factory_class"] = "NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle";
props["connection.provider"] = "NHibernate.Connection.DriverConnectionProvider";
props["dialect"] = "NHibernate.Dialect.MsSql2000Dialect";
props["connection.driver_class"] = "NHibernate.Driver.SqlClientDriver";
props["connection.connection_string"] = "<YOUR CONNECTION STRING HERE>";
props["connection.isolation"] = "ReadCommitted";
foreach (DictionaryEntry de in props)
{
config.Properties.Add(de.Key.ToString(), de.Value.ToString());
}
// Everything from here on out is the standard NHibernate calls
// you already use.
// Load mappings etc, etc
// . . .
_factory = config.BuildSessionFactory();
_session = _factory.OpenSession();
}
}
I know this is old but if you have not found a solution I hope this will help,
I created a solution that uses multisessionfactory using unhaddins (I made alterations to suit my needs).
Basically the multisession factory creates session factories for each database and stores in Application object.
Depending on the client the call to getfactory("name of factory from factory config file") returns correct database to query on.
You will have to alter your management module to support this and all of your repositories to support the change in management. This may be impractical at first but you have to alter them anyway. Your calls from your repository can be something like this:
public string getByName(string name)
{
return getByName(nHibernateSessionManager.SessionFactoryManager.GetFactory(Session["session variable that holds client session factory name that was set on login"]).GetCurrentSession(), name);
}
or (creating a method in the sessionmanager to return session of a given factory) your code could be like this
public string getByName(string name)
{
return getByName(nHibernateSessionManager.GetSession(Session["session variable that holds client session factory name that was set on login"]), name);
}

NHibernate crashes when being called from a web user control in ASP.Net

I have a very strange problem: NHibernate crashes when being called from a web user control.
I am working on a ASP.Net (2.0) web page which uses NHibernate to access a database.
And I have a simple factory class to access a column CurrentStepNumber in the table ProjectInfo:
public class ProjectEntity
{
private int? _currentStepNumber;
public virtual int? CurrentStepNumber
{
get { return _currentStepNumber; }
set { _currentStepNumber = value; }
}
public static ProjectWizardEntity GetById(int id, bool shouldLock)
{
return RepositoryFactory.ProjectWizardRepository.GetById(id, shouldLock);
}
public static ProjectWizardEntity GetById(int id)
{
return GetById(id, false);
}
public virtual void Save()
{
RepositoryFactory.ProjectWizardRepository.Save(this);
}
public virtual void SaveOrUpdate()
{
RepositoryFactory.ProjectWizardRepository.SaveOrUpdate(this);
}
}
This class is accessed via a proxy class, so that everytime a new value is assigned it is flushed to the database:
public class DBHelper
{
ProjectEntity _projectEntity;
ProjectEntity GetProjectEntity()
{
if (_projectEntity == null)
_projectEntity = //get or create a new one;
return _projectEntity ;
}
public int? CurrentStepNumber
{
get
{
return (CurrentProjectId > 0) ? CurrentProjectWizardEntity.CurrentStepNumber : 0;
}
set
{
if (CurrentProjectId > 0)
{
CurrentProjectWizardEntity.CurrentStepNumber = value;
CurrentProjectWizardEntity.SaveOrUpdate();
}
}
}
}
Now the problem:
When I access CurrentStepNumber from the test.aspx page, everything works perfectly
When I read this field from the web user control (test.ascx) which is used on test.aspx page it is still OK
However when I try to assign a value to CurrentStepNumber in the code behind the control (test.ascx) I always get an exception:
NHibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session
Actually SaveOrUpdate method of the NHibernate Repository throws the exception.
I could not figure out what could be the problem here, so any help will be appreciated.
I think that You have a session management problem here. How is RepositoryFactory.ProjectWizardRepository.GetById creating and possibly disposing the NHibernate session? Does it create and then close a session?
It seems that DBHelper.GetProjectEntity() is creating or loading a ProjectEntity. Later, when CurrentStepNumber's setter i called, You insert or update the object to the database.
The problem is that when DBHelper.GetProjectEntity() is loading an existing object and later closing the session after it has been loaded but keep the object around, we are entering deep water. When the object is later updated, You set a new value for CurrentStepNumber and send the object to NHibernate to save. The problem here is that the object is not associated with the new session that is created and closed during saving. Nhibernate then gets confused since a new object is discovered that is not loaded from current session but it has an id of an existing object.
For a solution, Google for "NHibernate asp.net session management" and You will get a number of good hits about how to use the ASP.NET request cycle as a unit of work.

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