Re: VS_VERSION_INFO static ctrl
On 13/06/2010 21:34, RB wrote:
Thanks Giovanni, worked like a charm, though I changed the
SetVersionString function to no args. I have a couple of
questions if you would be so kind. See code and comments
below. Questions are at very bottom in the OnInitDialog.
class CAboutDlg : public CDialog
{
private:
CString m_strVersion;
public:
void SetVersionString( );
If the SetVersionString method is not designed to be called from the
outside of the class, you could make it 'private' (so it can be
accessible only inside CAboutDlg class), or 'protected' (so it can be
accessible inside CAboutDlg class and classes derived from it).
BOOL CAboutDlg::OnInitDialog( )
{ //** Class Wizard added base call ** //
CDialog::OnInitDialog( );
//** being added code //
SetVersionString( ); // format the CString
HWND hDlg = m_CtrlStaticVer.GetSafeHwnd( );
//** Question 1.
//** here I used the API SetWindowText to get a return, the
// MFC SetWindowText was a void return, Is this a big deal ?
BOOL bResult = ::SetWindowText(hDlg, m_strVersion);
Frankly speaking, in MFC code I've always used CWnd::SetWindowText
method (not the global raw Win32 API ::SetWindowText).
e.g. considering the m_CtrlStaticVer control class, I would just write:
m_CtrlStaticVer.SetWindowText( someString );
However, you are right that the return value of ::SetWindowText is lost
in this case.
In VC10 (VS2010), the implementation of CWnd::SetWindowText is like this:
<code>
void CWnd::SetWindowText(LPCTSTR lpszString)
{
ENSURE(this);
ENSURE(::IsWindow(m_hWnd) || (m_pCtrlSite != NULL));
if (m_pCtrlSite == NULL)
::SetWindowText(m_hWnd, lpszString);
else
m_pCtrlSite->SetWindowText(lpszString);
}
</code>
So, the return value of ::SetWindowText is just discarded.
I would have preferred a method returning BOOL, to better wrap the raw
Win32 ::SetWindowText.
Note that ATL's CWindow::SetWindowText() correctly returns a BOOL, so it
is a better wrapper to ::SetWindowText:
http://msdn.microsoft.com/en-us/library/wfaxc8w5(VS.80).aspx
//**Question 2
//** Class Wizard put below return in ? when I had planned to return the
//** the result of the SetWindow, Can you explain what this is all about ?
return TRUE; // return TRUE unless you set the focus to a control
// EXCEPTION: OCX Property Pages should return FALSE
}
When you use a framework like MFC, it is better to follow the rules of
this framework, as indicated by the comments introduced by the MFC Wizard.
Note also that OnInitDialog method wraps the WM_INITDIALOG Win32
message, and in the "Return Value" paragraph you can read:
http://msdn.microsoft.com/en-us/library/ms645428(VS.85).aspx
<quote>
The dialog box procedure should return TRUE to direct the system to set
the keyboard focus to the control specified by wParam. Otherwise, it
should return FALSE to prevent the system from setting the default
keyboard focus.
</quote>
Giovanni