CameraController not defined

this is my code.. i have to add HVP3D dynamically..

string[] AllFiles = Directory.GetFiles(@"C:\Users\..", "*.3ds");
            HelixViewport3D[] hel_ar = new HelixViewport3D[AllFiles.Count()];
            
            for (int i = 0; i < AllFiles.Count(); i++)
            {
                hel_ar[i] = new HelixViewport3D();

                PerspectiveCamera myPCamera = new PerspectiveCamera();
                myPCamera.Position = new Point3D(10000, 0, 0);
                myPCamera.LookDirection = new Vector3D(-1, 0, 0);
                myPCamera.FieldOfView = 60;
                hel_ar[i].Viewport.Camera = myPCamera;
               
                DirectionalLight myDirectionalLight = new DirectionalLight();
                myDirectionalLight.Color = Colors.White;
                myDirectionalLight.Direction = new Vector3D(-0.61, -0.5, -0.61);
                hel_ar[i].Viewport.Height = 115;
                hel_ar[i].Viewport.Width = 115;
                
                Model3DGroup m3d = new Model3DGroup();
                m3d = ModelImporter.Load(AllFiles[i]);
                m3d.Children.Add(myDirectionalLight);
                ModelVisual3D m = new ModelVisual3D();
                m.Content = m3d;
                hel_ar[i].Viewport.Children.Add(m);
               
                
               stackPanel1.Children.Add(hel_ar[i]);
                                
            }