C++ C++；MFC:尝试使用类的实例调用方法时出现调试断言错误

我在test2.cpp中有这个函数

void Ctest2App::message(){
    MessageBox(0, L"And text here", L"MessageBox caption", MB_OK);

}

我用以下方式从test2Dlg调用它

void Ctest2Dlg::OnBnClickedButton1()
{
    Ctest2App t;
    t.message();
}

当我按下按钮时，我得到一个调试断言错误。为什么?

test2.cpp文件-

// test2.cpp : Defines the class behaviors for the application.
//

#include "stdafx.h"
#include "test2.h"
#include "test2Dlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif


// Ctest2App

BEGIN_MESSAGE_MAP(Ctest2App, CWinApp)
    ON_COMMAND(ID_HELP, &CWinApp::OnHelp)
END_MESSAGE_MAP()


// Ctest2App construction

Ctest2App::Ctest2App()
{
    // TODO: add construction code here,
    // Place all significant initialization in InitInstance
}


// The one and only Ctest2App object

Ctest2App theApp;


// Ctest2App initialization

BOOL Ctest2App::InitInstance()
{
    // InitCommonControlsEx() is required on Windows XP if an application
    // manifest specifies use of ComCtl32.dll version 6 or later to enable
    // visual styles.  Otherwise, any window creation will fail.
    INITCOMMONCONTROLSEX InitCtrls;
    InitCtrls.dwSize = sizeof(InitCtrls);
    // Set this to include all the common control classes you want to use
    // in your application.
    InitCtrls.dwICC = ICC_WIN95_CLASSES;
    InitCommonControlsEx(&InitCtrls);

    CWinApp::InitInstance();


    AfxEnableControlContainer();

    // Create the shell manager, in case the dialog contains
    // any shell tree view or shell list view controls.
    CShellManager *pShellManager = new CShellManager;

    // 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
    // Change the registry key under which our settings are stored
    // TODO: You should modify this string to be something appropriate
    // such as the name of your company or organization
    SetRegistryKey(_T("Local AppWizard-Generated Applications"));

    Ctest2Dlg dlg;
    m_pMainWnd = &dlg;
    INT_PTR nResponse = dlg.DoModal();
    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
    }

    // Delete the shell manager created above.
    if (pShellManager != NULL)
    {
        delete pShellManager;
    }

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

void Ctest2App::message(){
    MessageBox(0, L"And text here", L"MessageBox caption", MB_OK);

}

---

您已尝试创建第二个Ctest2App对象，但一个应用中只能有一个。MFC提供一个全局函数来访问已创建的应用程序对象：

AfxGetApp()->message();

---

它肯定与

Ctest2App

有关，因为调用

MessageBox

似乎没有问题。什么是

Ctest2App

？它是一个新创建的基于对话框的MFC项目。除了构造函数、对象和InitInstance之外，上面没有任何内容。