解决办法一：

在你要访问的地方的 .cpp 文件中加入

extern C***App theApp;

解决办法二：

得到指向app的指针

如 ((C***App *)AfxGetApp())->你的成员变量

 

我是在主程序的头文件里添加就可以了:

// five.h : main header file for the FIVE application // #if !defined(AFX_FIVE_H__0B197DD2_A92A_4BC8_9B02_88A17EC40DBE__INCLUDED_) #define AFX_FIVE_H__0B197DD2_A92A_4BC8_9B02_88A17EC40DBE__INCLUDED_ #if _MSC_VER > 1000 #pragma once #endif // _MSC_VER > 1000 #ifndef __AFXWIN_H__ #error include 'stdafx.h' before including this file for PCH #endif #include "resource.h"        // main symbols ///// // CFiveApp: // See five.cpp for the implementation of this class // class CFiveApp : public CWinApp {
   public:     CFiveApp(); // Overrides // ClassWizard generated virtual function overrides //{
    {AFX_VIRTUAL(CFiveApp)     public: virtual BOOL InitInstance(); //}}AFX_VIRTUAL // Implementation //{
    {AFX_MSG(CFiveApp) // NOTE - the ClassWizard will add and remove member functions here. //    DO NOT EDIT what you see in these blocks of generated code ! //}}AFX_MSG     DECLARE_MESSAGE_MAP() public:     CDatabase m_DB; }; extern CFiveApp theApp; ///// //{
    {AFX_INSERT_LOCATION}} // Microsoft Visual C++ will insert additional declarations immediately before the previous line. #endif // !defined(AFX_FIVE_H__0B197DD2_A92A_4BC8_9B02_88A17EC40DBE__INCLUDED_)