WF Activity得到Variable and Argument

  public   sealed   class  CustomActivity1 : NativeActivity
    {
         protected   override   void  Cancel(NativeActivityContext context)
        {
            Console.Write( " Cancel " );
             base .Cancel(context);
        }

         protected   override   void  Abort(NativeActivityAbortContext context)
        {
            Console.Write( " Abort " );
             base .Abort(context);
        }


         protected   override   void  CacheMetadata(NativeActivityMetadata metadata)
        {
            _locationReferences  =
                metadata.Environment.GetLocationReferences().ToList();

             base .CacheMetadata(metadata);
        }

         protected   override   void  Execute(NativeActivityContext context)
        {
            LocationReference locationReference  =
                _locationReferences.Find(
                    x  =>  x.Name  ==   " Test "   &&  x.Type  ==   typeof ( int ));

             if  (locationReference  !=   null )
            {
                Console.WriteLine(
                    locationReference.Name  +   "   "   +  locationReference.Type);

                 //  Blows up here.
                Location location  =  locationReference.GetLocation(context);
                location.Value  =   5 ;
            }
          //  var pi  =  context.GetType().GetProperty( " AllowChainedEnvironmentAccess " , BindingFlags.NonPublic  |  BindingFlags.Instance);
          //  pi.SetValue(context,  true ,  null );
             string  myVaraibleName  =   " varaibleX " ;
             string  myArgumentName  =   " argument1 " ;

             string  MyVariableValue  =  context.DataContext.GetProperties()[myVaraibleName].GetValue(context.DataContext).ToString();
             string  myArgument  =  context.DataContext.GetProperties()[myArgumentName].GetValue(context.DataContext).ToString();
            Console.Write( " Execute " );
            var extension  =  context.GetExtension < MyExtension > ();

        }

         private  List < LocationReference >  _locationReferences;


    }

     class  MyExtension : IWorkflowInstanceExtension
    {
         private  WorkflowInstanceProxy _instance;
         public  IEnumerable < object >  GetAdditionalExtensions()
        {
             return   null ;
        }
         public   void  SetInstance(WorkflowInstanceProxy instance)
        {
            _instance  =  instance;
        }
         public   void  WaitSome(Bookmark bookmark)
        {

             //   _instance.WorkflowDefinition

        }
    }