Sporadic null reference exception on multiple instances of Web Api

[Prashanth Benny]

I am facing an issue currently using Web API for a website using Autofac which i need to connect to the cross platform app.

The code breaks when i call the API(only on multiple instances).

I have done enough of search on documentation, forums and on Stack Overflow. but there was no solution to my issue.

the code produces an exception at

var scope = EngineContext.Current.ContainerManager.Scope()  --Null reference exception

I have tried debugging the code but the exception is not generated regularly.

but i found some points where it breaks.

var sis = EngineContext.Current.Resolve<StoreInformationSettings>()

 

I have tried loading it once again, inside while statement as

var sis = EngineContext.Current.Resolve<StoreInformationSettings>()`

while(sis == null) 

{

    sis = EngineContext.Current.Resolve<StoreInformationSettings>()

}

var webHelper = EngineContext.Current.Resolve<IWebHelper>(); 

even in here, i did the same thing which worked again

var webHelper = EngineContext.Current.Resolve<IWebHelper>();

while(webHelper == null)

{

    webHelper = EngineContext.Current.Resolve<IWebHelper>();

} 

and similarly, a few more instances. this suggests, it's loading but after a delay!

I have tried updating the Autofac Nuget package as instructed in some forum which failed again(i rolled back the version afterwards).

I am using MVC 4

Visual Studio 2015 

Autofac Version 3.5.2

this would be of great help, because I am currently stuck here. I cannot carry on further development because its breaking every now and then.

Thank you so much in advance for your help.

[Travis Illig]

What is "EngineContext"? That's not Web API or Autofac.

[Prashanth Benny]

Hello Travis, I am working on NopCommerce. Engine context is an interface to the AutoFac in nopcommerce.

[Travis Illig]

You may need to post this to a NopCommerce forum. I don't think anyone here can tell you why you might get a null reference in a NopCommerce component. We don't have any official support or integration for NopCommerce, so if it's integrated, it's something they hooked up.