Dewsoft Frontpage Tutorials

Lesson - 1 : Building Your First Windows Application
1.7 : Understanding the Components of a Dialog-Based Application
Dialog applications are much simpler than SDI and MDI applications. Create one called FirstDialog, with an About box, no Help, 3D controls, no automation, ActiveX control support, no sockets, source file comments, and MFC as a shared DLL. In other words, accept all the default options. Three classes have been created for you for the application called FirstMDI: CAboutDlg, a dialog class for the About dialog box CFirstDialogApp, a CWinApp class for the entire application CFirstDialogDlg, a dialog class for the entire application Listing 1.5 shows the header file for CFirstDialogApp. Listing 1.5 dialog16.h—Main Header File // FirstDialog.h : main header file for the FIRSTDIALOG application // #if !defined(AFX_FIRSTDIALOG_H__CDF38DB4_8718 _11D0_B02C_0080C81A3AA2__INCLUDED_) #define AFX_FIRSTDIALOG_H__CDF38DB4_8718 _11D0_B02C_0080C81A3AA2__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 //////////////////////////////////// // CFirstDialogApp: // See FirstDialog.cpp for the implementation of this class // class CFirstDialogApp : public CWinApp { public: CFirstDialogApp(); // Overrides // ClassWizard generated virtual function overrides //{{AFX_VIRTUAL(CFirstDialogApp) public: virtual BOOL InitInstance(); //}}AFX_VIRTUAL // Implementation //{{AFX_MSG(CFirstDialogApp) // 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() }; //////////////////////////////////////// //{{AFX_INSERT_LOCATION}} // Microsoft Developer Studio will insert additional declarations immediately // before the previous line. #endif // !defined(AFX_FIRSTDIALOG_H_ CDF38DB4_8718_11D0_B02C_0080C81A3AA2 ¬__INCLUDED_) CFirstDialogApp inherits from CWinApp, which provides most of the functionality. CWinApp has a constructor, which does nothing, as did the SDI and MDI constructors earlier in this unit, and it overrides the virtual function InitInstance(), as shown in Listing 1.6. Listing 1.6 FirstDialog.cpp CDialog16App::InitInstance() BOOL CFirstDialogApp::InitInstance() { AfxEnableControlContainer(); // Standard initialization // If you are not using these features and want to reduce the size // of your final executable, you should remove from the following // the specific initialization routines you don’t need. #ifdef _AFXDLL Enable3dControls(); // Call this when using MFC in a shared DLL #else Enable3dControlsStatic(); // Call this when linking to MFC statically #endif CFirstDialogDlg dlg; m_pMainWnd = &dlg; int 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 } // Because the dialog has been closed, return FALSE so that you exit the // application, rather than start the application’s message pump. return FALSE; } This enables 3D controls, because you asked for them, and then puts up the dialog box that is the entire application. To do that, the function declares an instance of CDialog16Dlg, dlg, and then calls the DoModal() function of the dialog, which displays the dialog box onscreen and returns IDOK if the user clicks OK, or IDCANCEL if the user clicks Cancel. It’s up to you to make that dialog box actually do something. Finally, InitInstance() returns FALSE because this is a dialog-based application and when the dialog box is closed, the application is ended. As you saw earlier for the SDI and MDI applications, InitInstance() usually returns TRUE to mean "everything is fine—run the rest of the application" or FALSE to mean "something went wrong while initializing." Because there is no "rest of the application," dialog-based apps always return FALSE from their InitInstance().

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