c# - StructureMap throws ArgumentNullException on HttpContext -

i'm having weird issue structuremap.mvc5

i created brand new mvc5 project in visual studio (default options asp.net mvc project left selected.)

i installed structuremap.mvc5 via nuget package manager (install-package structuremap.mvc).

i added following code to top of "homecontroller.cs" file:

namespace testmvc.controllers {     public interface itest     {         string testmessage();     }     public class test : itest     {         public string testmessage()         {             return "this worked again 23";         }     } 

i added constructor , private member follows:

public class homecontroller : controller {     private readonly itest _test;      public homecontroller(itest test)     {         _test = test;     } 

finally, updated action result follows:

public actionresult about() {     viewbag.message = _test.testmessage();      return view(); } 

the project compiles , start up. given default index page normal, somewhere between 2 , 5 seconds after page returned in browser, exception thrown in "structuremapdependencyscope.cs" on return line of method:

private httpcontextbase httpcontext {     {         var ctx = container.trygetinstance<httpcontextbase>();         return ctx ?? new httpcontextwrapper(system.web.httpcontext.current);     } } 

the exact error given is:

system.argumentnullexception unhandled user code   hresult=-2147467261   message=value cannot null. parameter name: httpcontext   paramname=httpcontext   source=system.web   stacktrace:        @ system.web.httpcontextwrapper..ctor(httpcontext httpcontext)        @ testmvc.dependencyresolution.structuremapdependencyscope.get_httpcontext() in d:\code\annies\anniesv4\anniesv4-bookingadministration\testmvc\dependencyresolution\structuremapdependencyscope.cs:line 69        @ testmvc.dependencyresolution.structuremapdependencyscope.get_currentnestedcontainer() in d:\code\annies\anniesv4\anniesv4-bookingadministration\testmvc\dependencyresolution\structuremapdependencyscope.cs:line 55        @ testmvc.dependencyresolution.structuremapdependencyscope.disposenestedcontainer() in d:\code\annies\anniesv4\anniesv4-bookingadministration\testmvc\dependencyresolution\structuremapdependencyscope.cs:line 90        @ testmvc.dependencyresolution.structuremapdependencyscope.dispose() in d:\code\annies\anniesv4\anniesv4-bookingadministration\testmvc\dependencyresolution\structuremapdependencyscope.cs:line 85        @ testmvc.app_start.structuremapmvc.end() in d:\code\annies\anniesv4\anniesv4-bookingadministration\testmvc\app_start\structuremapmvc.cs:line 44   innerexception:  

checking, system.web.httpcontext.current indeed null @ point.

if stop , restart project, same error occurs.
if press f5 continue, website continues function expected.
however, if, after pressing f5, wait few moments, stop , restart project, don't error again until make sort of code change , rebuild!

this seemingly makes 0 sense me!

anyways.. appreciated!

(using vs2015 enterprise rc if makes difference)

the problem in dispose of container. trying dispose nested container lives in httpcontext null in moment of disposal.

i made changes structuremapdependencyscope class in order avoid exception:

public icontainer currentnestedcontainer {         {         if (httpcontext == null)             return null;          return (icontainer)httpcontext.items[nestedcontainerkey];     }     set     {         httpcontext.items[nestedcontainerkey] = value;     } }  private httpcontextbase httpcontext {         {         var ctx = container.trygetinstance<httpcontextbase>();         if (ctx == null && system.web.httpcontext.current == null)             return null;          return ctx ?? new httpcontextwrapper(system.web.httpcontext.current);     } }