MFC integration QT verification and problem handling

MFC Integrate QT

MFC Integrate qt There are many examples online , I'm just recording the problems I encountered in the verification process , So that people with the same problem will not run into a wall .

1. Create a single mfc dll Unable to export

QWinWidget Classes and QmfcApp Class QT_QTWINMIGRATE_EXPORT export , But the output is always incomplete , Later, I defined an independent export instead of the original macro

#ifdef QGUI_EXPORTS
#define QGUI_API __declspec(dllexport)
#else
#define QGUI_API __declspec(dllimport)
#endif 

2. establish MFC After procedure , He quoted Qt File error

 error 	C2061	 Grammar mistakes :  identifier “n”	

original MFC Every cpp All in the document new It's overloaded ：

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

This leads to the following code new Execution call error of ：

  QT_TRY {
            while(current != to) {
                new (current) T(*reinterpret_cast<T*>(src));
                ++current;
                ++src;
            }

3. Generate QT After the project , Unable to run

After generation, you need to use windeployqt To publish , But I still can't run after publishing , Refer to other blogs , Turned out to be qtplugin Environment variables need to be configured
Error is as follows ：

	This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Add environment variables ：
QT_QPA_PLATFORM_PLUGIN_PATH=%QTDIR%/plugins

4. mfc When using multiple bytes, the input box is garbled ：

Wide bytes are used by default ,mfc Input box is OK , When it is changed to multi byte, there will be garbled , It turned out , May not apply to qMfcApp::run, Messages can also be routed correctly ：

int CMFCQtDlgTestApp::Run()
{

MainQTFrame mainUI;
mainUI.show();

//return QMfcApp::run(this);

return CWinAppEx::Run();

}

Reference website ：

mfc Integrate qt
To configure plugin environment variable