根据
this,无法将HRESULT错误代码转换为Win32错误代码.因此(至少我的理解),我使用FormatMessage为了生成错误消息(即
std::wstring Exception::GetWideMessage() const
{
using std::tr1::shared_ptr;
shared_ptr<void> buff;
LPWSTR buffPtr;
DWORD bufferLength = FormatMessageW(
FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS,NULL,GetErrorCode(),reinterpret_cast<LPWSTR>(&buffPtr),NULL);
buff.reset(buffPtr,LocalFreeHelper());
return std::wstring(buffPtr,bufferLength);
}
)不适用于HRESULT.
解决方法
这个答案结合了Raymond Chen的想法,并正确识别了传入的HRESULT,并使用正确的设备返回一个错误字符串来获取错误消息：
/////////////////////////////
// ComException
CString FormatMessage(HRESULT result)
{
CString strMessage;
WORD facility = HRESULT_FACILITY(result);
CComPtr<IErrorInfo> iei;
if (S_OK == GetErrorInfo(0,&iei) && iei)
{
// get the error description from the IErrorInfo
BSTR bstr = NULL;
if (SUCCEEDED(iei->GetDescription(&bstr)))
{
// append the description to our label
strMessage.Append(bstr);
// done with BSTR,do manual cleanup
SysFreeString(bstr);
}
}
else if (facility == FACILITY_ITF)
{
// interface specific - no standard mapping available
strMessage.Append(_T("FACILITY_ITF - This error is interface specific. No further information is available."));
}
else
{
// attempt to treat as a standard,system error,and ask FormatMessage to explain it
CString error;
CErrorMessage::FormatMessage(error,result); // <- This is just a wrapper for ::FormatMessage,left to reader as an exercise :)
if (!error.IsEmpty())
strMessage.Append(error);
}
return strMessage;
}
