Display help for dialog controls on the status bar

If the user passes the mouse over a button, extra help text for that button should appear in
the status bar. To use status bar to display extra help for dialog controls is preaty easy.

Every time the mouse passes over a window, the WM_SETCURSOR message is sent to the window’s owner.
If we catch the message through OnSetCursor, we can easy determine if the mouse is over a dialog
control. Then, assuming the control has a string resource with the same ID, we pass the ID to a
special function that sets the text in the first status bar pane.

1. Create function to handle WM_SETCURSOR

BOOL CAboutDlg::OnSetCursor(CWnd * pWnd, UINT nHitText, UINT message)
{
	// if the cursor is not over a child window control, revert
	// to the default status bar text

if(pWnd == this)
SetPaneText();
else
SetPaneText(pWnd->GetDlgCtrlID());

return CDialog::OnSetCursor(pWnd, nHitTest, message);
}

2. Handle WM_DESTROY message to restore status bar text

void CAboutDlg::OnDestroy()
{
	SetPaneText();
	CDialog::OnDestroy();
}

3. Add SetPaneText helper function

// this part goes to CAboutDlg class declaration
protected:
	void SetPaneText(UINT nID = 0);

// and this is function implementation
void CAboutDlg::SetPaneText(UINT nID)
{
if(nID == 0)
nID = AFX_IDS_IDLEMESSAGE;

CWnd * pWnd = AfxGetMainWnd()->GetDescendantWindow(AFX_IDW_STATUS_BAR);
if(pWnd)
{
AfxGetMainWnd()->SendMessage(WM_SETMESSAGESTRING, nID);
pWnd->SendMessage(WM_IDLEUPDATECMDUI);
pWnd->UpdateWindow();
}
}

4. And finally do not foget to add following include files

#include  // for WM_SETMESSAGESTRING and WM_IDLEUPDATECMDUI
#include  // for AFX_IDW_STATUS_BAR

Last updated: 11 May 1998