如文，如何获得他的实例？

[xiamouse7880]

CPatternDemoApp::CPatternDemoApp()
{
// TODO: add construction code here,
// Place all significant initialization in InitInstance
onrun=0;
}

//////////////////////////////////////////////////////////////////////////
// The one and only CPatternDemoApp object

CPatternDemoApp theApp;

//////////////////////////////////////////////////////////////////////////
// CPatternDemoApp initialization

BOOL CPatternDemoApp::InitInstance()
{
AfxEnableControlContainer();

// Standard initialization
// If you are not using these features and wish to reduce the size
// of your final executable, you should remove from the following
// the specific initialization routines you do not need.

#ifdef _AFXDLL
Enable3dControls(); // Call this when using MFC in a shared DLL
#else
Enable3dControlsStatic(); // Call this when linking to MFC statically
#endif

CPatternDemoDlg dlg;
m_pMainWnd = &dlg;
int nResponse = dlg.DoModal();

///////////////////
dlg.myapp = this; //???????????????????????????????????
//我想在这儿获得CPatternDemoApp的实例theApp
/////////////////

if (nResponse == IDOK)
{
// TODO: Place code here to handle when the dialog is
// dismissed with OK
}
else if (nResponse == IDCANCEL)
{
// TODO: Place code here to handle when the dialog is
// dismissed with Cancel
}

// Since the dialog has been closed, return FALSE so that we exit the
// application, rather than start the application's message pump.
return FALSE;
}

[ISunwu]

楼主怎么会有这么奇怪的要求？

[flyelf]

在需要的地方extern CPatternDemoApp theApp;这样就可以直接用这个全局变量了

[xiamouse7880]

是因为，我在CPatternDemoApp类中定义几个私有变量，在CPatternDemoApp构造时初始化，然后在CPatternDemoDlg类中使用这些变量，这就需要拿到CPatternDemoApp的实例，于是我就在CPatternDemoDlg中定义了一个CPatternDemoApp的变量，打算在CPatternDemoDlg创建实例时同时把CPatternDemoApp的实例给他

[ISunwu]

建议你使用flyelf(空谷清音)的方法。

[xiamouse7880]

我在PatternDemo.cpp中定义了extern CPatternDemoApp theApp;
可在PatternDemoDlg.cpp中不能用theApp，说时未定义，为什么？