NullReferenceException from MVC AppliationContextManager

[ajohnstone-ks]

I'm using Csla 7.0.4 on .Net Framework 4.7.2, with ASP.Net MVC 5 / WebApi. An API controller is calling some async data portal methods, but they are blowing up with a NullReferenceException from the Csla MVC ApplicationContextManager.

 at Csla.Web.Mvc.ApplicationContextManager.GetLocalContext()
 at Csla.ApplicationContext.get_LocalContext()
 at Csla.ApplicationContext.SetLogicalExecutionLocation(LogicalExecutionLocations location)
 at Csla.Server.DataPortal.ClearContext(DataPortalContext context)
 at Csla.Server.DataPortal.<Fetch>d__42.MoveNext()
 at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
 at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
 at Csla.Channels.Local.LocalProxy.<Fetch>d__18.MoveNext()
 at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
 at Csla.Channels.Local.LocalProxy.<Fetch>d__18.MoveNext()
 at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
 at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
 at Csla.DataPortal`1.<DoFetchAsync>d__19.MoveNext()
 at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
 at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
 at Csla.DataPortal`1.<FetchAsync>d__24.MoveNext()
 at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
 at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
 at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()

My configuration for Csla in the WebApi project

services
  .AddCsla(
    x => x.RegisterContextManager<Csla.Web.Mvc.ApplicationContextManager>()
	  .Data(
	    y => y.DefaultTransactionIsolationLevel(isolationLevel)
		      .DefaultTransactionTimeoutInSeconds(transactionTimeout)
			  .DefaultTransactionAsyncFlowOption(TransactionScopeAsyncFlowOption.Enabled)
	  )
	  .DataPortal(
	    y => y.AddServerSideDataPortal(
		  z => z.RegisterExceptionInspector<ExceptionInspector>()
		)
	)
);

The controller does this:

var reporterTask = GetReporterAsync(criteria);
var getTimeTask = serverTime.GetCurrentTimeInTimeZoneAsync("Eastern Standard Time");

await Task.WhenAll(reporterTask, getTimeTask);

We also away the actual call to the IDataPortal in both cases (both of the calls above call our factory classes, which have the IDataPortal injected.

Any ideas? Should I be forcing Csla to use whatever the normal ApplicationContextManager is?

[rockfordlhotka]

Are your factory classes injected into the controller then? So they are created via DI, allowing the DI container to resolve IDataPortal<T>?

[ajohnstone-ks]

So I've played with the sample I made, and it seems like with Csla 7 & MVC 5 on .Net framework doing any Async data portal operation will trigger the error.

[rockfordlhotka]

Repeatable errors are the easiest to debug

[ajohnstone-ks]

@rockfordlhotka I've added the relevant Csla projects to my sample solution so I could debug things better, and it seems if I add this to my Csla configuration:
.DataPortal(y => y.UseLocalProxy(z => z.FlowSynchronizationContext = true))

The the sample run correctly. I'm going to try it in my actual code, but does this seem like it should be the right solution to you? Are there any pitfalls you're aware of in doing this?

[rockfordlhotka]

You know, I seem to remember that ASP.NET did use synchronization contexts, so that config change probably does make sense.

[ajohnstone-ks]

@rockfordlhotka So that setting, along with correctly configuring DependencyResolver & using it in my filters seems to have done the trick and my webapi is working now. Thanks!