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dcarl · #1 (**permalink**) 02-11-2003

I have a vc++ dialog app with dialogs in a tab control. One of the dialogs has the mappoint control in it. When I try to call m_mappointcontrol->NewMap(northamerica) I get an access violation. I can only call the NewMap from a button on the actual dialog with the mappoint control.

Have you seen this behavior? Has anyone found a solution?

thanks in advance

discostu · #2 (**permalink**) 05-25-2005

I, too, get an access violation after I create a NewMap in my application. I made it so that when my app starts up, the MappointCtrl is hidden and there is a CListCtrl shown in the same place. I have a button that shows the MappointCtrl and hides the CListCtrl. The map shows up fine. And the first time I run the application after doing a "Rebuild All" it runs fine. But every time I run it after that I get an Access Violation and it shows me the dissassembly (which doesn't really help me figure out what's going on).

Code:

void CMainFrame::OnMapView( ) {
	CRouteProgressView* pRPV   = NULL;
	CRoadRunnerMobileApp* pApp = (CRoadRunnerMobileApp*)AfxGetApp();

	if (pApp != NULL)
		pRPV = pApp->pProgressView; // pointer to the dialog class with the controls
	else
		return;

	CListCtrl     *list = pRPV->getListCtrl();
	CMappointCtrl *map  = pRPV->getMapCtrl();

	if( !map->IsWindowVisible() ) {
		list->ShowWindow( SW_HIDE );	
		map->ShowWindow( SW_SHOW );
		map->SetActiveWindow();
		pRPV->createNewMap();
	} else {
		map->CloseMap();
		list->ShowWindow( SW_SHOW );	
		map->ShowWindow( SW_HIDE );
	}

}

--------------------------------
class CRouteProgressView : public CFormView
{
...
	CMappointCtrl* getMapCtrl()  { return &m_Map; };
	CListCtrl*     getListCtrl() { return &m_List; };
	void createNewMap() {
		VARIANT a;
		a.vt = VT_I4;
		a.lVal = 1; // 1 for America 2 for geoMapEurope!
		m_Map.NewMap(a);
	};
...}

Any ideas? Thanks!

dcarl · #3 (**permalink**) 05-25-2005

The interface changes in the .net ide aka (vc++7.0) and fixes this.

**Wilfried** · #4 (**permalink**) 05-26-2005

Hi,

Quote:

Originally Posted by dcarl

I have a vc++ dialog app with dialogs in a tab control. One of the dialogs has the mappoint control in it. When I try to call m_mappointcontrol->NewMap(northamerica) I get an access violation. I can only call the NewMap from a button on the actual dialog with the mappoint control.

You mean the dialog is created but not visible ? Yes, if that's the case you must show it (modal or not), then load the map and eventually hide it if you want. If you dont want to have the map visible for a moment you can make it zero pixels height/width, or put another control above it.

**Wilfried** · #5 (**permalink**) 05-26-2005

Hi,

Quote:

Originally Posted by discostu

the first time I run the application after doing a "Rebuild All" it runs fine. But every time I run it after that I get an Access Violation

There is no difference between the first run after a rebuild and supsequent runt, however it is possible that you still have a mappoint instance running in memory for a while, if your application does not do a nice cleanup for some reason.

Eventually check with task manager, or make a small application that remove all mappoint instances out of memory before a second run to see if that is the reason.

To remove all mappoint instances there is example of it in FAQ.

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