Sample: WrapTBar.exe Wraps Toolbar During CFrameWnd Resizing (201009)

SUMMARY

WrapTBar.exe is a sample that demonstrates how to implement a toolbar that wraps according to the parent frame size. When the parent CFrameWnd is resized, the toolbar checks whether the new window width is wide enough to display all the buttons on the same row; if not, the toolbar wraps accordingly.

If your application requires that all toolbar buttons be accessible at all times, or if it allows the user to customize the toolbar by adding new buttons, you might decide to use this enhancement. The drawback of this sample is that it requires a fixed-size, nondockable toolbar. If you need to implement this behavior for dockable toolbars too, you might need to subclass the docking bar window, associated with the CDockBar class, and provide a new handler for WM_SIZEPARENT message.

MORE INFORMATION

The following files are available for download from the Microsoft Download Center:

WrapTBar.exe

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to Obtain Microsoft Support Files from Online Services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.

   File Name                Size
   ---------------------------------------------------------

   WrapFixedToolBar.h,      Implement the CToolBar-derived class
   WrapFixedToolBar.cpp     that would provide the desired behavior.
   WrapToolBar.h            The main header file (CWrapToolBarApp class).
   WrapToolBar.cpp          The main application source file.
   WrapToolBar.rc           Listing of all Windows resources used.
   res\WrapToolBar.ico      Icon file.
   res\WrapToolBar.rc2      Resources not edited by the IDE.
   WrapToolBar.clw          Information used by ClassWizard.
   MainFrm.h,
   MainFrm.cpp              The frame class CMainFrame.
   res\Toolbar.bmp          Used to create tiled images for the toolbar.
   WrapToolBarDoc.h,
   WrapToolBarDoc.cpp       The document CWrapToolBarDoc.
   WrapToolBarView.h,
   WrapToolBarView.cpp      The view of the document.
   StdAfx.h,
   StdAfx.cpp               Used to build a precompiled header (PCH) file.
   Resource.h               Defines new resource IDs.

The core of this solution relies on handling the MFC private WM_SIZEPARENT message. This message is sent to all child-windows of CFrameWnd-derived classes when the frame window is resized, ensuring the proper negotiation of the client space.

By deriving a new class from CToolBar and providing a handler for WM_SIZEPARENT, we solve the problem. The handler resembles the following:

LRESULT CWrapFixedToolBar::OnSizeParent(WPARAM, LPARAM lParam)
{
    AFX_SIZEPARENTPARAMS* lpLayout = (AFX_SIZEPARENTPARAMS*)lParam;
    DWORD dwStyle = RecalcDelayShow(lpLayout);

    if ((dwStyle & WS_VISIBLE) && (dwStyle & CBRS_ALIGN_ANY) != 0)
    {
        CRect rect;
        rect.CopyRect(&lpLayout->rect);
        // Reposition buttons on toolbar according to available space.
        SetWidth(rect.Width());
        // Pass message processing to base class handler.
        CToolBar::OnSizeParent(0, lParam);
    }
    return 0;
}

The CWrapFixedToolBar::SetWidth() function should be implemented as:

void CWrapFixedToolBar::SetWidth(long lWidth)
{
    TBBUTTON* pData;
    // Read the toolbar buttons.
    int nCount = GetToolBarCtrl().GetButtonCount();
    if (nCount != 0)
    {
        pData = new TBBUTTON[nCount];
        for (int i = 0; i < nCount; i++)
            _GetButton(i, &pData[i]);
    }
    else
        return;

    // Get the toolbar buttons offsets in the toolbar area.
    CRect rect;
    rect.SetRectEmpty();
    CalcInsideRect(rect, TRUE);

    // Wrap buttons according to available space.
    WrapToolBar(pData, nCount, lWidth - abs(rect.Width()));

    // Save toolbar buttons to underlying toolbar control.
    if (nCount != 0)
        for (int i = 0; i < nCount; i++)
            _SetButton(i, &pData[i]);

    if (pData)
        delete [] pData;
}

Finally, change the toolbar creation code in CMainFrame::OnCreate() to make it CBRS_SIZE_FIXED and to disable the docking capabilities.