MFC-GetMainWnd获取主窗口指针

CWinApp* pwin = NULL;
void CAfxGetAppDlg::OnBnClickedButton1()
{
    // TODO: 在此添加控件通知处理程序代码

    pwin= AfxGetApp();//获取当前应用进程的指针
    CWnd* pWnd = pwin->GetMainWnd();//获取主窗口指针
    CAfxGetAppDlg* pDlg= (CAfxGetAppDlg*)pWnd;
    //主窗口指针转化成对话框类指针
    pDlg->SetWindowText(_T("练习"));
    
    CWnd* pWnd1=pWnd->GetDlgItem(IDC_BUTTON1);//获取按钮的句柄
    pWnd1->SetWindowText(_T("获取进程指针"));
}