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我已經繼承了當前正在從其CView::OnBeginPrinting重寫中查詢ADODB數據庫的程序的維護。但是，當ADODB數據庫句柄是進程外數據庫連接的代理時，它經常崩潰 - 顯然，在等待RPC響應時，繪製消息導致它重新輸入CView的呈現處理，導致事情變得非常困惑。在CView中使用COM RPC :: OnBeginPrinting
有沒有一種方法可以安全地使用來自CView::OnBeginPrinting的過程對象的COM？例如，如果我能阻止窗口消息有問題的窗口，直到COM調用完成，這可能會工作...
這裏就是斷言發生的堆棧跟蹤：
mfc100d.dll!CPreviewDC::ReleaseOutputDC() Line 138 C++ (asserts here)
mfc100d.dll!CPreviewView::OnDraw(CDC * pDC) Line 801 C++
mfc100d.dll!CView::OnPaint() Line 189 C++
mfc100d.dll!CWnd::OnWndMsg(unsigned int message, unsigned int wParam, long lParam, long * pResult) Line 2354 C++
mfc100d.dll!CWnd::WindowProc(unsigned int message, unsigned int wParam, long lParam) Line 2067 + 0x20 bytes C++
mfc100d.dll!AfxCallWndProc(CWnd * pWnd, HWND__ * hWnd, unsigned int nMsg, unsigned int wParam, long lParam) Line 248 + 0x1c bytes C++
mfc100d.dll!AfxWndProc(HWND__ * hWnd, unsigned int nMsg, unsigned int wParam, long lParam) Line 411 C++
mfc100d.dll!AfxWndProcBase(HWND__ * hWnd, unsigned int nMsg, unsigned int wParam, long lParam) Line 420 + 0x15 bytes C++
[email protected]() + 0x28 bytes
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mfc100d.dll!COleMessageFilter::OnMessagePending(const tagMSG * __formal) Line 114 C++
mfc100d.dll!COleMessageFilter::XMessageFilter::MessagePending(HTASK__ * htaskCallee, unsigned long dwTickCount, unsigned long __formal) Line 312 C++
ole32.dll!CCliModalLoop::HandlePendingMessage() + 0x91de bytes
ole32.dll!CCliModalLoop::HandleWakeForMsg() + 0x46 bytes
ole32.dll!CCliModalLoop::BlockFn() - 0x34d92 bytes
ole32.dll!ModalLoop() + 0x5b bytes
ole32.dll!ThreadSendReceive() + 0x36c bytes
ole32.dll!CRpcChannelBuffer::SwitchAptAndDispatchCall() + 0x4d bytes
ole32.dll!CRpcChannelBuffer::SendReceive2() + 0x8d bytes
ole32.dll!CCliModalLoop::SendReceive() + 0x1e bytes
ole32.dll!CAptRpcChnl::SendReceive() + 0x1a25 bytes
ole32.dll!CCtxComChnl::SendReceive() + 0x47 bytes
[email protected]() + 0x40 bytes
rpcrt4.dll!_NdrClientCall2() - 0xa83 bytes
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ole32.dll!CStdMarshal::Begin_RemQIAndUnmarshal1() + 0x91 bytes
ole32.dll!CStdMarshal::Begin_QueryRemoteInterfaces() + 0x46 bytes
ole32.dll!CStdMarshal::QueryRemoteInterfaces() + 0x37 bytes
ole32.dll!CStdIdentity::CInternalUnk::QueryMultipleInterfaces() - 0x2adf0 bytes
ole32.dll!CStdIdentity::CInternalUnk::QueryInterface() + 0x30 bytes
[email protected]() + 0x16 bytes
jscript.dll!VAR::SetHeapObject() + 0x31 bytes
jscript.dll!VAR::Import() + 0x45d bytes
jscript.dll!VarList::ImportVar() + 0x2e bytes
jscript.dll!VarList::ImportRgvar() - 0x160fb bytes
jscript.dll!CSession::Execute() + 0xd6 bytes
jscript.dll!NameTbl::InvokeDef() + 0x146 bytes
jscript.dll!NameTbl::InvokeEx() - 0x42f bytes
jscript.dll!IDispatchExInvokeEx2() + 0x8e bytes
jscript.dll!IDispatchExInvokeEx() + 0x4f bytes
jscript.dll!NameTbl::InvokeEx() - 0x18653 bytes
msscript.ocx!CScriptControl::ModuleRun() + 0x171 bytes
msscript.ocx!CScriptControl::Run() + 0x5d bytes
[several levels of my code, which I cannot reveal]
myapp.exe!MyView::OnBeginPrinting(CDC * pDC, CPrintInfo * pInfo) Line 92 C++
mfc100d.dll!CPreviewView::SetPrintView(CView * pPrintView) Line 370 C++
mfc100d.dll!CView::DoPrintPreview(unsigned int nIDResource, CView * pPrintView, CRuntimeClass * pPreviewViewClass, CPrintPreviewState * pState) Line 218 + 0xc bytes C++
mfc100d.dll!AFXPrintPreview(CView * pView) Line 298 + 0x1b bytes C++
您是否真的看到該方法重新進入？ – sharptooth 2010-07-20 08:38:11
'OnBeginPrinting'本身不會被重新輸入，但它會進入'CPreviewView :: OnDraw'，然後由於'm_hDC'爲空而在'CPreviewDC :: ReleaseOutputDC'中聲明。 – bdonlan 2010-07-20 16:18:12