Simple Way to Check All Dialog Controls for Changings

It is very difficult and toilsome to implement code that checks every single control on a given dialog for changes; especially for complex dialogs. Normally you have to check all fields when the dialog was closed (let's say in OnOK) or have to catch all events like EN_CHANGED or BN_CLICKED to notice a changing. But fortunately the MFC provides a method to do such checkings in a very easy and compact way. This magical function calls
ON_CONTROL_RANGE ( wNotifyCode, id1, id2, memberFxn )

Use this macro to map a contiguous range of control IDs to a single message handler function for a specified Windows notification message. ClassWizard does not support creating an ON_CONTROL_RANGE handler in the user interface, so you must place the macro yourself. Be sure to put it outside the message map //{{AFX_MSG_MAP delimiters. Once entered, ClassWizard will parse these entries and allow you to browse them just like any other message map entries.

The BN_KILLFOCUS notification code is sent when a button loses the keyboard focus. The button must have the BS_NOTIFY style to send this notification message.

Usage

  1. Add the message handlers declaration...
  2. BEGIN_MESSAGE_MAP(CMyDlg, CDialog)
     //{{AFX_MSG_MAP(CMyDlg)
     ON_WM_CREATE()
     //}}AFX_MSG_MAP
    
     ON_CONTROL_RANGE(EN_CHANGE, IDC_EDIT1, IDC_EDIT3, OnRangeUpdateED)
     ON_CONTROL_RANGE(BN_CLICKED , IDC_RADIO1, IDC_RADIO8, OnRangeUpdateRB)
     ON_CONTROL_RANGE(BN_KILLFOCUS , IDC_CHECK1, IDC_CHECK6, OnRangeUpdateCB)
    END_MESSAGE_MAP()
    
  3. Declare the function in your header file that way:
  4. class CMyDlg : public CDialog
    {
    public:
     BOOL m_bUpdateED;
     BOOL m_bUpdateRB;
     BOOL m_bUpdateCB;
    	...
    
    protected:
     // Generated message map functions
     //{{AFX_MSG(CMyDlg)
     afx_msg int OnCreate(LPCREATESTRUCT lpCreateStruct);
     virtual BOOL OnInitDialog();
     virtual void OnOK();
     //}}AFX_MSG
     DECLARE_MESSAGE_MAP()
    
     virtual void OnRangeUpdateED(UINT nID);
     virtual void OnRangeUpdateRB(UINT nID);
     virtual void OnRangeUpdateCB(UINT nID);
    };
    
  5. And finally code your 'OnRangeUpdate...' functions that way:
  6. void CMyDlg::OnRangeUpdateED(UINT nID)
    {
     // extra check
     if ( SendDlgItemMessage(nID, EM_GETMODIFY, 0, 0) )
      m_bUpdateED = TRUE;
     else
      m_bUpdateED = FALSE;
    }
    
    void CMyDlg::OnRangeUpdateRB(UINT nID)
    {
     // for example
     if ( nID == IDC_RADIO3 )
      m_bUpdateRB = TRUE;
     else
      m_bUpdateRB = FALSE;
    }
    
    void CMyDlg::OnRangeUpdateCB(UINT nID)
    {
     // for example
     LRESULT lResult = SendDlgItemMessage(nID, BM_GETSTATE, 0, 0);
     if ( lResult == BST_CHECKED )
      m_bUpdateCB = TRUE;
     else
      m_bUpdateCB = FALSE;
    }
    
    void CMyDlg::OnOK() 
    {
     if ( m_bUpdateRB )
     // ...
    
     CDialog::OnOK();
    }