A question of dynamically moving controls (Drag and Drop)

=?Utf-8?B?Q2FtZXJvbl9D?= <CameronC@discussions.microsoft.com>
Wed, 3 Mar 2010 05:53:02 -0800
Hello again folks,
I am having a little issue with this and would appreciate any thoughts.
I have an application where I have a number of button controls that the User
can drag and drop around the screen.
This works fine.
The dropped positions are saved in the registry and when the User opens the
application again later, the controls are where ever they moved them to. And
this al;so appears to work fine.
However, I noticed that when I run on a smaller physical screen, and the
display scrolls I have an issue.
This is difficult for me to explain, but, say the actual display is twice
the size of the physical view. The User can scroll down, and drag a control
up to move it. Let's say they move it to two inches from the top of the
physical view, which is somewhere in the middle of the dialog window.
On the display it now all looks great.
However, later when the User restarts, the moved control now appears about
two inches from the top of the physical display, rather than in the middle of
the dialog.

This is the snippet I use to read the values from the registry
    Fetch the Button's Position from the Registry
    Note that the position was written in the Formview, so the position
    is relative to the Formview (X and Y values).
void CDragDropButton::GetButtonPropertiesFromRegistry(int iCtrlID)
    CWinApp* pApp = AfxGetApp();
    CString strSection, strKey, strResource;
    strSection.Format(_T("%s-%d"), strResource, iCtrlID);
    CRect rcNewPosition;

    rcNewPosition.top = pApp->GetProfileInt(strSection, strKey + _T("_X"), -1);
    rcNewPosition.left = pApp->GetProfileInt(strSection, strKey + _T("_Y"), -1);
    rcNewPosition.bottom = pApp->GetProfileInt(strSection, strKey +
_T("_HEIGHT"), -1);
    rcNewPosition.right = pApp->GetProfileInt(strSection, strKey +
_T("_WIDTH"), -1);
    if ((rcNewPosition.top != -1) && (rcNewPosition.bottom != -1) &&
(rcNewPosition.left != -1) && (rcNewPosition.right != -1))
        MoveWindow(rcNewPosition.top, rcNewPosition.left, rcNewPosition.right,


and this is a snippet of what I use to save the values in the registry
    The Left Mouse Button Up has been deteected.
    If we were dragging something, drop it wherever we are,
    and move the object to the new location.
    Write the new position information into the registry.
    Fire the event off to the Formview.
void CChiroPracticeOfficeView::OnLButtonUp(UINT nFlags, CPoint point)
    TRACE(_T("ChiroPracticeOfficeView OnLButtonUp.\n"));
    if (m_bButtonDragging)
        TRACE(_T("ChiroPracticeOfficeView OnLButtonUp. Caught a Dragging situation
and released capture.\n"));

        CPoint pt (point); //Get current mouse coordinates
        ClientToScreen (&pt); //Convert to screen coordinates
        // Get the CWnd pointer of the window that is under the mouse cursor
        CWnd* pDropWnd = WindowFromPoint (pt);
        ASSERT (pDropWnd); //make sure we have a window pointer

            We need to determine if we are "permitted" to Drop
            onto the window underneath
        if ((CWnd*) this == pDropWnd) //We Can only Drop onto the View
            CRect rc;
            m_pddbDragging->MoveWindow(point.x, point.y, rc.Width(), rc.Height());
            CWinApp* pApp = AfxGetApp();
            CString strSection, strKey, strResource;
            strSection.Format(_T("%s-%d"), strResource,
            pApp->WriteProfileInt(strSection, strKey + _T("_X"), point.x);
            pApp->WriteProfileInt(strSection, strKey + _T("_Y"), point.y);
            pApp->WriteProfileInt(strSection, strKey + _T("_Width"), rc.Width());
            pApp->WriteProfileInt(strSection, strKey + _T("_Height"), rc.Height());
    m_bButtonDragging = FALSE;
    CFormView::OnLButtonUp(nFlags, point);

Thanks for any ideas.

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