Re: CFormView and scrolling

From:

mosfet <john.doe@anonymous.org>

Newsgroups:

microsoft.public.vc.mfc

Date:

Fri, 20 Jul 2007 17:36:35 +0200

Message-ID:

<46a0d684$0$1616$426a34cc@news.free.fr>

AliR (VC++ MVP) a ?crit :

What is it that you are trying to do? That's not very clear in your post.

AliR.

"mosfet" <john.doe@anonymous.org> wrote in message
news:46a07c5f$0$9922$426a74cc@news.free.fr...

Hi,

I am developping on pocket pc an application with some views deriving
from CFormView.
On this platform you cannot resize your MainFrame because it's always
maximized.
So let's say I have a CAboutView and inside it I am putting some controls
outside the client rect, for now here is what I am doing to have the
scrollbar appeared :

void CAboutView::OnWindowPosChanged( WINDOWPOS* lpwndpos )
if ( rcItem.bottom > rc.bottom ) {
// Scroll bar info
SetScrolling( TRUE );
SetScrollPos( SB_VERT, 0 );
SetScrollSizes( MM_TEXT, CSize( rc.Width(), rcItem.bottom + 2) );

}
else {
// Scroll bar info
SetScrollSizes( MM_TEXT, rc.Size() );
}
}

So basically I am taking the last controls and I resize my scrollbars.

But I am not very satisfied by this solution, do you have a better idea ?

Ok What I want to do is to be able to scroll a view deriving from a
CFormView on a smartphone knowing that on this platform you cannot move
scollbars "by hand". For that you have to use keypad.
The problem is usually a WM_KEYDOWN is eaten in the PreTranslateMessage.

So when I have a CFormView with some controls(listboxes for instance) on
it, a WM_KEYDOWN is receive in the PreTranslate and after the
shell/OS/framework(I don't know who exactly) move the focus from one
control to another.

Now consider the case :

We have a view with one vertical scrollbar and one static control to
display some text and a CStaticlink(CButton) to open a URL when clicking
on it.

If I want to be able to move my scrollbar I do the following

UINT CBaseView::OnGetDlgCode()
{
if (m_nScrollPolicy == 0)
    return (DLGC_WANTCHARS | DLGC_HASSETSEL | DLGC_WANTARROWS |
DLGC_WANTALLKEYS);
    else
    return ( CFormView::OnGetDlgCode() );
}

I receive the WM_GETDLGCODE and I say that my view wants to receive
WM_KEYDOWN.
When I receive the WM_KEYDOWN I call OnVScroll to move my view BUT the
problem is if I do that my CStaticlink cannot get focus and I cannot
click on it.

void CBaseView::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)
{
    ...
    switch (nChar)
    {
    case VK_UP:
        nVPos = ((nVPos - 15) < 0) ? 0 : nVPos - 15;
        OnVScroll(SB_THUMBTRACK, nVPos,NULL);
        break;
    case VK_DOWN:
        OnVScroll(SB_THUMBTRACK,nVPos + 15,NULL);
        break;
    case VK_LEFT:
        nHPos = ((nHPos - 15) < 0) ? 0 : nHPos - 15;
        OnHScroll(SB_THUMBTRACK,nHPos,NULL);
        break;
    case VK_RIGHT:
        nHPos += 15;
        OnHScroll(SB_THUMBTRACK,nHPos,NULL);
        break;
    }
}

So to fix it I would need inside the OnKeyDown to check if the next tab
control is on screen and in this case instead of calling OnVScroll maybe
  I should set focus to my CStaticlink.
And what if a ClistView get the focus, normally each call to WM_KEYDOWN
should move the item and not the focus.

ANOTHER problem is that this first case relies on the fact that I
receive the WM_GETDLGCODE and it's not always the case. it works ONLY if
my view doesn't have a focus on a control.