描述:
程序中调用
CoInitializeEx(NULL, COINIT_MULTITHREADED)
后再调用GetOpenFileName 或 GetSaveFileName 或 mfc 的CFileDialog，都有可能出现程序死锁文件对话框无法弹出的情况。并且这种情况在某些机器上会出现，在另一些机器上就不出现，机器硬件相同，和操作系统也没关系，同样的系统，同样的硬件，一台上有问题，另一台上就没问题，十分困惑。
谁能帮我解决问题，将另外赠送100分，更多也行，我有的是分。
解决方案1:
PRB: Oleaut32 Hidden Window Blocks Apps Broadcasting Messages
ID: Q189427
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The information in this article applies to:
Microsoft Win32 Software Development Kit (SDK)
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SYMPTOMS
An application that calls certain OLE Automation functions can block the global broadcast of Windows messages. For example, when a user double- clicks a desktop icon, the program associated with the icon might be blocked from starting and Windows Explorer might hang.
CAUSE
Certain Automation APIs (example:VariantChangeType) cause OLEAut32.dll to create a hidden top-level window that processes the WM_WININICHANGE message (for example, to get notifications like time zone changes, and so forth). This is used to invalidate OLE Automation's national language setting (NLS) cache. If the thread that called this function does not service the message queue, the hidden top-level window is starved of messages. Any global broadcast of messages using the SendMessage API will cause the broadcasting application to block indefinitely. Under the MTA programming model, a thread is not obligated to service the message queue. Hence an MTA thread that calls these Automation APIs can cause this problem.
RESOLUTION
There is no fixed set of OLE Automation APIs that create the hidden top- level window. However, the hidden top-level window is created the first time Ole Automation runtime needs to look at the NLS information. To work around this, spin a secondary thread and call an OLE Automation API first on the secondary thread (for example, VariantChangeType, changing from BSTR). This creates the hidden top-level window the secondary thread, and then pumps messages on the secondary thread. As a result, the hidden top- level window does not block broadcast messages. You can continue to use your automation methods in other threads. Send a WM_ QUIT message or use another form of inter-thread communication from the primary thread to end the secondary thread.
STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this bug and will post new information here in the Microsoft Knowledge Base as it becomes available.
MORE INFORMATION
Steps to Reproduce Behavior
Use the following code to develop a console application:
Sample Code
#define _WIN32_DCOM
#include <windows.h>
void main()
{
CoInitializeEx(NULL, COINIT_MULTITHREADED);
VARIANT var,var1;
VariantInit(&var);
VariantInit(&var1);
BSTR str = SysAllocString(L"Test");
var.vt = VT_BSTR;
var.bstrVal = str;
VariantChangeType(&var, &var, 0, VT_I2);
VariantClear(&var);
VariantClear(&var1);
while (1)
{
;
}
CoUninitialize();
}
Run this application. Run another application that broadcasts a message (for example, double click a .doc icon on the desktop). A message is broadcast to all the top-level windows that are using either SendMessage or a non-blocking variation of the SendMessage API (such as SendMessageTimeout). The broadcasting application is either blocked (hung) indefinitely or hung for the period of time it takes the call to timeout.
One work around for the problem is to create a secondary thread from the primary thread. After you have done this, call an automation method on the secondary thread's procedure (the secondary thread will create the hidden top-level window). Create a message loop to process the messages in the secondary thread. After everything is finished, close the secondary thread from the primary thread. Since there is a message pump in the secondary thread, any broadcasted message will be processed.
Sample Code
#define _WIN32_DCOM
#include <windows.h>
HANDLE g_EventHandle;
DWORD WINAPI SecondaryThread(LPVOID pInputParam)
{
HRESULT hr = S_OK;
//&nb