Background: I developed an Activex control in .NET, but found it was causing stability issues in various applications that used it. I managed to find a series of steps, from sample applications, similar unstabilities outlined below.
I have a sample Activex control that I've downloaded from the Dev-Center website called 'CSActivex' (http://code.msdn.microsoft.com/windowsdesktop/CSActiveX-b86194f8)
It was fairly easy to build, I just loaded the project up in VS2010 Express (C#) and it compiled into a .dll
I then created a sample MFC application from VS2008 C++ to model a legacy applications (it does not use any .NET). The target is the simple dialog based GUI that has an About box.
I registered the csactivex.dll with regasm and just copied the dll to the VS IDE folder, so I can insert the Activex control at design time, and then to the Debug folder, so it can be found during runtime.
At design time, I insert the CSActivex control onto the About dialog box, it appears with no surprises. After building and copying the dll to the Debug folder and run a debug session, if I continually navigate to the about box, click in various places on the control, close the about dialog and repeat a few times, I start to see messages in the output log about access violations, and it starts to look like this:
'CSActivexMFC.exe': Loaded 'C:\WINDOWS\assembly\NativeImages_v2.0.50727_32\System.Windows.Forms\63406259e94d5c0ff5b79401dfe113ce\System.Windows.Forms.ni.dll'
'CSActivexMFC.exe': Loaded 'C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\mscorjit.dll'
'CSActivexMFC.exe': Loaded 'C:\WINDOWS\WinSxS\x86_Microsoft.Windows.GdiPlus_6595b64144ccf1df_1.0.2600.5581_x-ww_dfbc4fc4\GdiPlus.dll'
'CSActivexMFC.exe': Loaded 'C:\WINDOWS\assembly\NativeImages_v2.0.50727_32\Accessibility\11eb4f6606ba01e5128805759121ea6c\Accessibility.ni.dll'
First-chance exception at 0x00000000 in CSActivexMFC.exe: 0xC0000005: Access violation reading location 0x00000000.
First-chance exception at 0x00000000 in CSActivexMFC.exe: 0xC0000005: Access violation reading location 0x00000000.
First-chance exception at 0x79f4c2f7 in CSActivexMFC.exe: 0xC0000005: Access violation reading location 0x0000000b.
First-chance exception at 0x79f4c2f7 in CSActivexMFC.exe: 0xC0000005: Access violation reading location 0x0000000b.
While it does not crash in the debugger, I can't help but think this in not good, and I have a feeling that it may be related to the instability of other .NET Activex controls. If I can figure out a way to solve this issue, the same resolution may help the original control.
I tried breaking on the exception, but it appears to happen in a few different places. one stack trace when I closed the applications is below:
mscorwks.dll!79f4c2f7() [Frames below may be incorrect and/or missing, no symbols loaded for mscorwks.dll]
mscorwks.dll!79f4c370() mscorwks.dll!79faaa91()
mscorwks.dll!79faa858() mscorwks.dll!79faa9ad()
mscorwks.dll!79faa9d9() mscorwks.dll!7a079480()
mscorwks.dll!7a0798e8() mscorwks.dll!7a043f25()
ole32.dll!77525834() rpcrt4.dll!77e799f4()
rpcrt4.dll!77ef421a() ntdll.dll!7c915239()
ntdll.dll!7c91542b() ntdll.dll!7c91534a()
ntdll.dll!7c915239() ntdll.dll!7c91542b()
ntdll.dll!7c91534a() ntdll.dll!7c915f75()
ntdll.dll!7c9155ed() ntdll.dll!7c915ce9()
ntdll.dll!7c96f07c() ole32.dll!77600c15()
ole32.dll!77600bbf() ole32.dll!7752ad31()
ole32.dll!7752ac56() ole32.dll!7752b771()
ole32.dll!77600e1f() ole32.dll!7752b7ab()
ole32.dll!7752b5e1() ole32.dll!7752b54e()
user32.dll!7e418734() ole32.dll!7752b54e()
ole32.dll!7752b54e() ole32.dll!7752b54e()
ole32.dll!7752b54e() ole32.dll!7752f2d0()
ole32.dll!7752f23e() ole32.dll!77557237()
mscorwks.dll!79f9e14d() mscorwks.dll!79f9e0b4()
mscorwks.dll!79f9e018() mscorwks.dll!79f4c879()
mscorwks.dll!79f3bb76() mscoreei.dll!603cc966()
mscoreei.dll!603d1f25() mscoree.dll!790186ad()msvcr90d.dll!_crtCorExitProcess(int status=2) Line 716 C msvcr90d.dll!_crtExitProcess(int status=2) Line 722 + 0x9 bytes C msvcr90d.dll!doexit(int code=2, int quick=0, int retcaller=0) Line 644 + 0x9 bytes C msvcr90d.dll!exit(int code=2) Line 412 + 0xd bytes C CSActivexMFC.exe!__tmainCRTStartup() Line 595 C CSActivexMFC.exe!wWinMainCRTStartup() Line 399 C kernel32.dll!7c817077()
I was hoping someone may have run into this before, I'm running into this on mulitple machines (home and at work) and at least have it narrowed down to either a problem with CSActivex not doing something it should, or something in MFC.
so my question is how to get these samples working without the access violations?
Edit:
Just opening the about window and closing it repeatedly eventually results in a crash in the debugger (unhandled exception) with a stack trace below, to me it looks like an object that was destructed is being destroyed again?
First-chance exception at 0x00400003 in CSActivexMFC.exe: 0xC0000005: Access violation writing location 0x00000000.
First-chance exception at 0x00400003 in CSActivexMFC.exe: 0xC0000005: Access violation writing location 0x00000000.
First-chance exception at 0x003a005c in CSActivexMFC.exe: 0xC0000096: Privileged instruction.
First-chance exception at 0x00460020 in CSActivexMFC.exe: 0xC0000005: Access violation reading location 0x00460020.
First-chance exception at 0x78b6ba1d (mfc90ud.dll) in CSActivexMFC.exe: 0xC0000005: Access violation writing location 0x00000018.
Unhandled exception at 0x78b6ba1d (mfc90ud.dll) in CSActivexMFC.exe: 0xC0000005: Access violation writing location 0x00000018.
mfc90ud.dll!CDataSourceControl::~CDataSourceControl() Line 2431 + 0x2d bytes C++
mfc90ud.dll!CDataSourceControl::`scalar deleting destructor'() + 0x11 bytes C++
mfc90ud.dll!COleControlSite::~COleControlSite() Line 77 + 0x22 bytes C++
mfc90ud.dll!COleControlSite::`scalar deleting destructor'() + 0x11 bytes C++
mfc90ud.dll!COleControlSiteOrWnd::~COleControlSiteOrWnd() Line 161 + 0x24 bytes C++
mfc90ud.dll!COleControlSiteOrWnd::`scalar deleting destructor'() + 0x11 bytes C++
mfc90ud.dll!COleControlContainer::~COleControlContainer() Line 199 + 0x1c bytes C++
mfc90ud.dll!COleControlContainer::`scalar deleting destructor'() + 0x11 bytes C++
mfc90ud.dll!CWnd::OnDestroy() Line 786 + 0x24 bytes C++
mfc90ud.dll!CWnd::OnWndMsg(unsigned int message=2, unsigned int wParam=0, long lParam=0, long * pResult=0x0012f510) Line 2042 C++
mfc90ud.dll!CWnd::WindowProc(unsigned int message=2, unsigned int wParam=0, long lParam=0) Line 1755 + 0x20 bytes C++
mfc90ud.dll!AfxCallWndProc(CWnd * pWnd=0x0012f88c, HWND__ * hWnd=0x002c04fc, unsigned int nMsg=2, unsigned int wParam=0, long lParam=0) Line 240 + 0x1c bytes C++
mfc90ud.dll!AfxWndProc(HWND__ * hWnd=0x002c04fc, unsigned int nMsg=2, unsigned int wParam=0, long lParam=0) Line 403 C++
mfc90ud.dll!AfxWndProcBase(HWND__ * hWnd=0x002c04fc, unsigned int nMsg=2, unsigned int wParam=0, long lParam=0) Line 441 + 0x15 bytes C++
user32.dll!7e418734()
[Frames below may be incorrect and/or missing, no symbols loaded for user32.dll]
user32.dll!7e418816()
mfc90ud.dll!CThreadSlotData::GetThreadValue(int nSlot=6623744) Line 268 C++
user32.dll!7e428eec()
ntdll.dll!7c90e473()
user32.dll!7e42b1a8()
mfc90ud.dll!CWnd::DestroyWindow() Line 1007 + 0xd bytes C++
90909090()
