C++ / MFC: CDockablePane in CMDIChildWndEx

Question

I want to create two CDockablePane objects in my MDI child window. Initally, they should be docked to the bottom but the user shall have the possibility to float them. I started with the code created by the MFC project wizard. Then I moved the code from the class representing the main frame to the class representing the child frame (CChildFrame). I ended up with this:

int CChildFrame::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
    if (CMDIChildWndEx::OnCreate(lpCreateStruct) == -1) {
        return -1;
    }

    EnableDocking(CBRS_ALIGN_ANY);
    EnableAutoHidePanes(CBRS_ALIGN_ANY);

    // Create left window and dock to ChildFrame
    m_wndOutput.Create(_T("Left pane"), this, CRect(0, 0, 200, 200), TRUE, ID_VIEW_OUTPUTWND, WS_CHILD | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN | CBRS_BOTTOM | CBRS_FLOAT_MULTI);
    m_wndOutput.EnableDocking(CBRS_ALIGN_ANY);
    DockPane(&m_wndOutput);

    // Create right window and dock to the left pane
    m_wndProperties.Create(_T("Right pane"), this, CRect(0, 0, 200, 200), TRUE, ID_VIEW_PROPERTIESWND, WS_CHILD | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN | CBRS_RIGHT | CBRS_FLOAT_MULTI);
    m_wndProperties.EnableDocking(CBRS_ALIGN_ANY);
    m_wndProperties.DockToWindow (&m_wndOutput, CBRS_ALIGN_RIGHT);

    return 0;
}

First of all, the panes were not able to float. I could fix this by adding the following statement to my CChildFrame constructor:

CMDIChildWndEx::m_bEnableFloatingBars = TRUE;

This solved the not-floating problem, but I doubt that this is the canonical solution for the problem. Can anyone judge that? How do you solve that problem?

The problem I was not able to solve is that the panes initially have height = 0. Interestingly, if I open a second or third child frame of the same class, it works and they are initially visible (with height = 200). If I close them all and open a new one, the height is 0 again and only the slider appears which I can use for adjusting the height. However, I need to be able to really see the panels also for the first child frame.

If I shall provide more sample code, please let me know. If I'm doing something completely wrong (is it supported to have panes in a child frame?), please also let me know.

I guess that the problem described in the following link is the same. But there is no answer to that question. https://social.msdn.microsoft.com/forums/en-US/7494e84f-e5fd-4726-b8fe-9c702c7e25f1/cmdichildwndex-and-cdockablepane-issue

Have you read this: codeproject.com/Articles/493218/Understanding-CDockablePane ? I found it cleared up many things that were fuzzy for me about CDockablePane, although I had gotten most things to work with trial and error over the years. — Roel
Yes, I read that. All the samples there use the main frame for adding the dockable panes. — JohnQQ

Robson Robson · Accepted Answer · 2017-05-18T09:02:28

sadly this is coming 2 years later =)

but I just solved the problem using the method SetMinSize, that is inherited from CPane, after the pane's creation.

m_wndProperties.SetMinSize(CSize(200,200));

C++ / MFC: CDockablePane in CMDIChildWndEx

2 Answers