nhibernate CurrentSessionContext.Hasbind giving object reference not set - c#-4.0

Question

Hi i m using WebApi Mvc4 framework .net 4.0
I create a sessionFactory as follows:
public void ConfigureNHibernate(IKernel container)
{
var sessionFactory = FluentNHibernate
.Cfg.Fluently.Configure()
.Database(
MsSqlConfiguration.MsSql2008.ConnectionString(
c => c.FromConnectionStringWithKey("ApikeysDb")))
.CurrentSessionContext("web")
.Mappings(m => m.FluentMappings.AddFromAssemblyOf<CTP.ApiNext.Data.SqlServer.SqlCommandFactory>())
.BuildSessionFactory();
// Add the ISessionFactory instance to the container
container.Bind<ISessionFactory>().ToConstant(sessionFactory);
// Configure a resolver method to be used for creating ISession objects
container.Bind<ISession>().ToMethod(CreateSession);
container.Bind<ICurrentSessionContextAdapter>().To<CurrentSessionContextAdapter>();
}
and below when I am binding my ISession object to the HTTP context, I am getting error "Object reference not set"
public ISession CreateSession(IContext context)
{
var sessionFactory = context.Kernel.Get<ISessionFactory>();
if (!CurrentSessionContext.HasBind(sessionFactory))
{
// Open new ISession and bind it to the current session context
var session = sessionFactory.OpenSession();
CurrentSessionContext.Bind(session);
}
return sessionFactory.GetCurrentSession();
}
The error is at at line: CurrentSessionContext.HasBind(sessionFactory)
The error details are:
[NullReferenceException: Object reference not set to an instance of an object.]
lambda_method(Closure , Object ) +73
NHibernate.Context.ReflectiveHttpContext.get_HttpContextCurrentItems() +84
NHibernate.Context.WebSessionContext.GetMap() +52
NHibernate.Context.MapBasedSessionContext.get_Session() +70
NHibernate.Context.CurrentSessionContext.HasBind(ISessionFactory factory) +71
CTP.ApiNext.Web.Api.App_Start.NinjectConfigurator.CreateSession(IContext context) in C:\Projects\UNILEVER\WHITELABEL\_api-next\ctp-api-next\src\CTP.ApiNext.Web.Api\App_Start\NinjectConfigurator.cs:91
Ninject.Activation.Providers.CallbackProvider`1.CreateInstance(IContext context) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\CallbackProvider.cs:45
Ninject.Activation.Provider`1.Create(IContext context) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Provider.cs:38
Ninject.Activation.Context.Resolve() in c:\Projects\Ninject\ninject\src\Ninject\Activation\Context.cs:157
Ninject.<>c__DisplayClass10.<Resolve>b__c(IBinding binding) in c:\Projects\Ninject\ninject\src\Ninject\KernelBase.cs:386
System.Linq.WhereSelectEnumerableIterator`2.MoveNext() +145
System.Linq.Enumerable.SingleOrDefault(IEnumerable`1 source) +4077101
Ninject.Planning.Targets.Target`1.GetValue(Type service, IContext parent) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Targets\Target.cs:197
Ninject.Planning.Targets.Target`1.ResolveWithin(IContext parent) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Targets\Target.cs:165
Ninject.Activation.Providers.StandardProvider.GetValue(IContext context, ITarget target) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:114
Ninject.Activation.Providers.<>c__DisplayClass4.<Create>b__2(ITarget target) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:96
System.Linq.WhereSelectArrayIterator`2.MoveNext() +66
System.Linq.Buffer`1..ctor(IEnumerable`1 source) +216
System.Linq.Enumerable.ToArray(IEnumerable`1 source) +77
Ninject.Activation.Providers.StandardProvider.Create(IContext context) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:96
Ninject.Activation.Context.Resolve() in c:\Projects\Ninject\ninject\src\Ninject\Activation\Context.cs:157
Ninject.<>c__DisplayClass10.<Resolve>b__c(IBinding binding) in c:\Projects\Ninject\ninject\src\Ninject\KernelBase.cs:386
System.Linq.WhereSelectEnumerableIterator`2.MoveNext() +145
System.Linq.Enumerable.SingleOrDefault(IEnumerable`1 source) +4077101
Ninject.Planning.Targets.Target`1.GetValue(Type service, IContext parent) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Targets\Target.cs:197
Ninject.Planning.Targets.Target`1.ResolveWithin(IContext parent) in c:\Projects\Ninject\ninject\src\Ninject\Planning\Targets\Target.cs:165
Ninject.Activation.Providers.StandardProvider.GetValue(IContext context, ITarget target) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:114
Ninject.Activation.Providers.<>c__DisplayClass4.<Create>b__2(ITarget target) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:96
System.Linq.WhereSelectArrayIterator`2.MoveNext() +66
System.Linq.Buffer`1..ctor(IEnumerable`1 source) +216
System.Linq.Enumerable.ToArray(IEnumerable`1 source) +77
Ninject.Activation.Providers.StandardProvider.Create(IContext context) in c:\Projects\Ninject\ninject\src\Ninject\Activation\Providers\StandardProvider.cs:96
Ninject.Activation.Context.Resolve() in c:\Projects\Ninject\ninject\src\Ninject\Activation\Context.cs:157
Ninject.<>c__DisplayClass10.<Resolve>b__c(IBinding binding) in c:\Projects\Ninject\ninject\src\Ninject\KernelBase.cs:386
System.Linq.WhereSelectEnumerableIterator`2.MoveNext() +145
System.Linq.<CastIterator>d__b1`1.MoveNext() +85
System.Linq.Enumerable.Single(IEnumerable`1 source) +191
Ninject.ResolutionExtensions.Get(IResolutionRoot root, IParameter[] parameters) in c:\Projects\Ninject\ninject\src\Ninject\Syntax\ResolutionExtensions.cs:37
CTP.ApiNext.Web.Api.App_Start.NinjectWebCommon.RegisterServices(IKernel kernel) in C:\Projects\UNILEVER\WHITELABEL\_api-next\ctp-api-next\src\CTP.ApiNext.Web.Api\App_Start\NinjectWebCommon.cs:61
CTP.ApiNext.Web.Api.App_Start.NinjectWebCommon.CreateKernel() in C:\Projects\UNILEVER\WHITELABEL\_api-next\ctp-api-next\src\CTP.ApiNext.Web.Api\App_Start\NinjectWebCommon.cs:48
Ninject.Web.Common.Bootstrapper.Initialize(Func`1 createKernelCallback) in c:\Projects\Ninject\Ninject.Web.Common\src\Ninject.Web.Common\Bootstrapper.cs:50
CTP.ApiNext.Web.Api.App_Start.NinjectWebCommon.Start() in C:\Projects\UNILEVER\WHITELABEL\_api-next\ctp-api-next\src\CTP.ApiNext.Web.Api\App_Start\NinjectWebCommon.cs:27
[TargetInvocationException: Exception has been thrown by the target of an invocation.]
System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) +0
System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments) +192
System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) +108
System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters) +19
WebActivator.BaseActivationMethodAttribute.InvokeMethod() +236
WebActivator.ActivationManager.RunActivationMethods() +534
WebActivator.ActivationManager.RunPreStartMethods() +41
WebActivator.ActivationManager.Run() +64
[InvalidOperationException: The pre-application start initialization method Run on type WebActivator.ActivationManager threw an exception with the following error message: Exception has been thrown by the target of an invocation..]
System.Web.Compilation.BuildManager.InvokePreStartInitMethodsCore(ICollection`1 methods, Func`1 setHostingEnvironmentCultures) +550
System.Web.Compilation.BuildManager.InvokePreStartInitMethods(ICollection`1 methods) +132
System.Web.Compilation.BuildManager.CallPreStartInitMethods(String preStartInitListPath) +90
System.Web.Compilation.BuildManager.ExecutePreAppStart() +135
System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +516
[HttpException (0x80004005): The pre-application start initialization method Run on type WebActivator.ActivationManager threw an exception with the following error message: Exception has been thrown by the target of an invocation..]
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +9873912
System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +101
System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +456
I read so many posts, but no avail.
I have a MessageHandler (invoked by ninject), which invokes ISession, when I comment it out, the problem goes away. Why?
GlobalConfiguration.Configuration.MessageHandlers.Add(kernel.Get());

Answer 1

Your Factory and Session interfaces are not bound correctly. You have to set the scope as part of the Binding (InSingletonScope for the Factory as you only ever need one of these, and InThreadScope for the Session). This is so Ninject knows when to inject an existing reference or create a new instance of each type.
Try modifying your configuration to the following:
public void ConfigureNHibernate(IKernel container)
{
var sessionFactory = FluentNHibernate
.Cfg.Fluently.Configure()
.Database(
MsSqlConfiguration.MsSql2008.ConnectionString(
c => c.FromConnectionStringWithKey("ApikeysDb")))
.CurrentSessionContext("web")
.Mappings(m => m.FluentMappings.AddFromAssemblyOf<CTP.ApiNext.Data.SqlServer.SqlCommandFactory>());
// Bind the ISession Factory - Singleton as only ever need one of these
container.Bind<ISessionFactory>().ToMethod(x =>configuration.BuildSessionFactory()).InSingletonScope();
// Bind the ISession
container.Bind<ISession>().ToMethod(c => c.Kernel.Get<ISessionFactory>().OpenSession()).InThreadScope();
}
To test the above you can immediately try to instantiate a Factory:
var sessionFactory = Kernel.Get<ISessionFactory>();