MFC how to know a resizing of view is finished - mfc

Question

I am wondering how to catch the fact that a view (CView in a CMDIChildWnd frame) has been resized, and that the user just released the left mouse button.
None of OnSize, OnSizing and OnLButtonUp work.
I have tried the solution in http://www.codeguru.com/forum/showthread.php?t=59476 and it doesn't work.
I am working on VC2010 with W7.
Thanks in advance.

Answer 1

Try WM_NCLBUTTONUP. I don't know if a view can be resized other than by the mouse, but if it can you probably also want to respond to WM_EXITSIZEMOVE as in the link you gave.

Answer 2

I recently needed to do this. I used a combination of OnSysMessage to capture the SC_SIZE and SC_MOVE event and WM_ENTERSIZEMOVE and WM_EXITSIZEMOVE within the CMDIChildWnd derived class. Within the OnSysMessage handler I set a public variable for IsSizing. I can then check the variable within the OnEnterSizeMove function and act accordingly. Within the OnExitSizeMove function, it resets the variable to FALSE.
BEGIN_MESSAGE_MAP(CChildFrame, CMDIChildWnd)
//{{AFX_MSG_MAP(CChildFrame)
ON_WM_SYSCOMMAND()
ON_MESSAGE(WM_ENTERSIZEMOVE, OnEnterSizeMove)
ON_MESSAGE(WM_EXITSIZEMOVE, OnExitSizeMove)
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
And for the handlers:
void CChildFrame::OnSysCommand(UINT nID, LPARAM lParam)
{
switch(nID&0xfff0)
{
case SC_SIZE:
m_bIsSizing = TRUE;
break;
case SC_MOVE:
m_bIsSizing = FALSE;
break;
}
CMDIChildWnd::OnSysCommand(nID, lParam);
}
LRESULT CChildFrame::OnEnterSizeMove(UINT wParam, LPARAM lParam)
{
if(m_bIsSizing)
{
TRACE("CChildFrame::OnEnterSizeMove\n");
}
return 0; //don't flag we processed the message
}
LRESULT CChildFrame::OnExitSizeMove(UINT wParam, LPARAM lParam)
{
if(m_bIsSizing)
{
TRACE("CChildFrame::OnExitSizeMove\n");
m_bIsSizing = FALSE; // set to false before calling OnSizing
CRect dlgRect;
pView->GetClientRect(dlgRect);
pView->InvalidateRect(NULL, FALSE);
pView->SendMessage(WM_SIZE, WPARAM(SIZE_RESTORED), MAKELONG(dlgRect.Width(), dlgRect.Height()));
}
return 0; //don't flag we processed the message
}
Then within your View code, you can check if the Frame is sizing within your OnSize handler.
void CMyView::OnSize(UINT nType, int cx, int cy)
{
CChildFrame* pFrame=(CChildFrame*)GetParentFrame();
if(!pFrame->m_bIsSizing) {
CWaitCursor cur;
//DO UPDATE CODE
}
}