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…

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()

2. Declare the function in your header file that way:

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);
};

3. And finally code your ‘OnRangeUpdate…’ functions that way:

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();
}