Codejock Developer Community : Attached pane window being deleted under me

Attached pane window being deleted under me : I think the point is that simply...

Tue, 09 Mar 2010 04:05:59 +0000

Author: adrien
Subject: 16394
Posted: 09 March 2010 at 4:05am

I think the point is that simply changing the docking of a pane shouldn't call DestroyWindow on it.

Personally I consider this a bug.

Attached pane window being deleted under me : Hi;You attach the created...

Tue, 09 Mar 2010 03:38:08 +0000

Author: mgampi
Subject: 16394
Posted: 09 March 2010 at 3:38am

Hi;
You attach the created window to the docking pane. So it takes control. I just tried your steps and in my case I catch a ShowWindow message in OnDockingPaneNotify. All I have to do is check the window handle of my control and then recreate it if necessary. It works very well.
If you require information about the window destroyed, just call an appropriate function in your OnDestroy message handler, but perhaps you could change your dashboard window to a singleton...

Attached pane window being deleted under me : mgampi, you're sort of right....

Mon, 08 Mar 2010 19:19:19 +0000

Author: Aaron Koolen
Subject: 16394
Posted: 08 March 2010 at 7:19pm

mgampi, you're sort of right. In order to match up our internal objects with the correct pane we need to save a mapping between pane id and our objects (Dashboard). When we get a XTP_DPN_SHOWWINDOW message, we look to see if we have a mapping for that pane id already. If we do, we just attach the dashboard window to it. If we don't, then we create a new dashboard (Which does create a window, yes) and then attach that.

I understand what you're saying in that the panel should be checked that it's valid, but unfortunately that's not exactly the problem.

When this code is called (During the first time a pane is shown) the panel windows are created fine, and they show up. It's later on, when they are undocked and docked again in some strange manner, that for some reason the CodeJock framework is calling DestroyWindow on it, which inevitably destroys my dashboard window, even though my application doesn't know that it has. From that point on the window handle is invalid.

I'm trying to work out if this is normal. Can CodeJock destroy windows that you've created and put into panes, whenever it feels like? If so, then I will need to trap that and have some sort of observer pattern so things can be told when it's destroyed. If not, then is it a bug?

Thanks for your help

Attached pane window being deleted under me : Hi; am I right when I assume...

Mon, 08 Mar 2010 18:33:08 +0000

Author: mgampi
Subject: 16394
Posted: 08 March 2010 at 6:33pm

Hi;

am I right when I assume that below code creates the underlying window too? If this is true then you have to check in the Attach section whether the window handle is still valid or not!

                       DashboardPanel *panel = new DashboardPanel(SOME ID);
                       pPane->Attach(panel);

I do it this way:

                case IDR_TIMESCALE:
                    {
                        if (_timeline.GetSafeHwnd() == 0)
                        {
                            VERIFY(_timeline.Create(WS_CHILD|WS_VISIBLE|XRTLS_HASONLINEBUTTON|XRTLS_HASPRESELECTCOMBO|XRTLS_HASTWOTIMELINES, this, 0)==TRUE);
                        }
                        pPane->Attach(&_timeline);

Attached pane window being deleted under me : on this note, it would be really...

Mon, 08 Mar 2010 18:10:45 +0000

Author: adrien
Subject: 16394
Posted: 08 March 2010 at 6:10pm

on this note, it would be really useful to be able to store an ID with a pane, so we can match things up on loading layouts.

p.p.s this is on 13.3.0

Attached pane window being deleted under me : Hi there. I can't give you...

Mon, 08 Mar 2010 17:24:03 +0000

Author: Aaron Koolen
Subject: 16394
Posted: 08 March 2010 at 5:24pm

Hi there. I can't give you the whole handler but here's a trimmed down version with some stuff obviously replaced but with all the code handling code there. Let me know if you need more.


     if (wParam == XTP_DPN_ACTION)

     {

          XTP_DOCKINGPANE_ACTION* pAction = (XTP_DOCKINGPANE_ACTION*)lParam;

          switch( pAction->action ) 

          {

              �case xtpPaneActionActivated:

              �{

                            DO PANEL ACTIVATION INTERNAL STUFF 

              �}

              �break;

          }

          return TRUE;

     }



     if (wParam == XTP_DPN_SHOWWINDOW)

     {

          CXTPDockingPane* pPane = (CXTPDockingPane*)lParam;

          int paneID = pPane->GetID();

          if (!pPane->IsValid() ) 

          {

              �int paneID = pPane->GetID();

              �DashboardPanelCollection::iterator pos =  m_dashboardPanels.find(paneID);              �

                        if ( pos == m_dashboardPanels.end() )

              �{

                     � DashboardPanel *panel = new DashboardPanel(SOME ID);

                     � pPane->Attach(panel);

              �} 

              �else

              �{                    

                    pPane->Attach(pos->second);

              �}              �

          }  else {

              �DashboardPanel* panel = (DashboardPanel*)pPane->GetChild();

               INTERNAL ACTIVATION CODE FOR panel

          }

          return TRUE; // handled

     }

Thanks
Aaron

Attached pane window being deleted under me : Hi;Could you show me your OnDockingPaneNotify...

Mon, 08 Mar 2010 16:57:54 +0000

Author: mgampi
Subject: 16394
Posted: 08 March 2010 at 4:57pm

Hi;
Could you show me your OnDockingPaneNotify message handler?

Attached pane window being deleted under me : Hi all. Due to the lack of documentation...

Mon, 08 Mar 2010 16:32:39 +0000

Author: Aaron Koolen
Subject: 16394
Posted: 08 March 2010 at 4:32pm

Hi all. Due to the lack of documentation I can't really find out if this is normal behaviour but I've had an issue appear where the CXTPDockingPaneMiniWnd is deleting the window I have attached to a pane from underneath me.

Here is my setup.

- I run my application and create 3 tabbed panes docked together.

- Undock them as a group by double clicking title bar.

- Pull one off from the other two so I now have two pane windows, one with two tabbed panes in it, and one with one in it.

- Double click the single pane title bar, it redocks.

- Double click the dual pane title bar, it redocks.

- Then I double click AGAIN, the title bar of the docked group and they undock back to a set of two and a single pane.

- Double click the single pane title bar to dock it back and BAM!

The application dies in my code because it tries to use was window it created that was deleted from underneath it by the last docking operation.

Stack trace inside CodeJock:


CXTPDockingPaneMiniWnd::OnChildContainerChanged(CXTPDockingPaneBase * 0x0677b858) line 260 + 23 bytes

CXTPDockingPaneSplitterContainer::OnChildContainerChanged(CXTPDockingPaneBase * 0x0677b858) line 478 + 23 bytes

CXTPDockingPaneTabbedContainer::RemovePane(CXTPDockingPaneBase * 0x0677ac00) line 399 + 48 bytes

CXTPDockingPaneManager::_RemovePane(CXTPDockingPaneBase * 0x0677ac00) line 479 + 23 bytes

CXTPDockingPaneManager::_AttachPane(CXTPDockingPaneBase * 0x0677ac00, CXTPDockingPaneBase * 0x0676fd48) line 506

CXTPDockingPaneManager::AttachPane(CXTPDockingPaneBase * 0x0677ac00, CXTPDockingPaneBase * 0x0676fd48) line 485

CXTPDockingPaneManager::_ToggleDocking(CXTPDockingPane * 0x0677abe0 {CXTPDockingPane}, CXTPDockingPaneBase * 0x0676fd48) line 770

CXTPDockingPaneManager::ToggleDocking(CXTPDockingPaneBase * 0x067790f8) line 719 + 60 bytes

CXTPDockingPaneMiniWnd::OnNcLButtonDblClk(unsigned int 2, CPoint {x=957 y=142}) line 585



The offending method is:



void CXTPDockingPaneMiniWnd::OnChildContainerChanged(CXTPDockingPaneBase* /*pContainer*/)

{

     if (!m_hWnd)

          return;



     if (m_pTopContainer == NULL || m_pTopContainer->IsEmpty())

     {

          DestroyWindow();

     }

     else

     {

          m_bDelayInvalidate = TRUE;

          PostMessage(WM_IDLEUPDATECMDUI);

     }

}

DestroyWindow() is called which ends up destroying the window inside that pane.

Is this normal behaviour? If it is, it means I need to track when my windows are deleted and any code the references those or tracks those needs to be notified.

Can someone explain this to me please.

Thanks
Aaron

NOTE: This has happened with 13.2 and 13.3.