WTL MDI command bar control

• Download demo project - 44 Kb
• Download source - 5 Kb

Introduction

This is a CCommandBarCtrl extension to fully support the MDI architecture.

The implementation consists of three classes:

• CCommandBarCtrl2 manages the additional MDI buttons.
• CMDIChildWindowImpl2 forwards the size changes to CCommandBarCtrl2.
• CMDIChildWinImplTraits2 implements a helper class to keep the maximize state when creating a new MDI child window.

The class definitions and implementations are in the file AtlCmdBar2.h, which is included in the demo project.

Requirements

You will require the WTL Libraries; these can be downloaded from the Microsoft site. If the WTL Libraries have no meaning to you, see Introduction to WTL - Part 1.

How to use the control in your WTL App

First, include the file AtlCmdBar2.h in your applications .cpp file. Then replace the definition of the main frames command bar CCommandBarCtrl m_CmdBar; with CCommandBarCtrl2 m_CmdBar; in mainfrm.h. Finally replace all instances of CMDIChildWindowImpl with CMDIChildWindowImpl2 in ChildFrm.h. That's all.

History

03 Oct 2001

Initial public release.

06 Dec 2001

Added chevron support (including menu band size update).

Fixed MDI system menu injection.

Fixed size problem of MDI system menu.

Fixed flickering of menu bar during window sizing.

About the implementation

The additional MDI buttons are implemented as custom draw buttons of the menu toolbar and are drawn via DrawFrameControl(). These are added/removed in respond to a size change of the MDI child window. Additionally, WM_MDISETMENU has to be handled to insert the MDI child windows menu into the new frame window menu.

Below are detailed explanations of the most interesting functions.

CCommandBarCtrl2

LRESULT OnMDISetMenu(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)

Checks, if the MDI child is maximized and modifies the given frame menu before it will be passed to the CCommandBarCtrl handler. Because the menu toolbar is build in the default handler the MDI buttons are added after the call.

LRESULT OnMDIChildSized(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM lParam, BOOL& /*bHandled*/)

Message send from CMDIChildWindowImpl2 when the size of the MDI child window has been changed. Modifies the menu accordingly to the state of the MDI child. The return value is non-zero if the MDI child is maximized.

LRESULT OnHookMouseMove(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& bHandled)

Because the file menu button will be drawn as selected when the cursor will be moved over the MDI child icon this handler resets the current hot item.

void UpdateGapWidth()

Updates the width of the gap between the last menu item and the MDI buttons. Called in respond to a size change of the command bar.

bool UpdateMenu(bool fShow, HMENU hMenu)

Inserts or removes the MDI child window menu into the given menu.

void UpdateMDIButtons(bool fShow)

Adds or removes the MDI buttons to the menu toolbar.

void MDIChildChanged(HWND hWndMDIChild)

Modifies the menu and the toolbar according to the state of the given MDI child window.

CMDIChildWindowImpl2

HWND Create(HWND hWndParent, _U_RECT rect = NULL, LPCTSTR szWindowName = NULL, DWORD dwStyle = 0, DWORD dwExStyle = 0, UINT nMenuID = 0, LPVOID lpCreateParam = NULL)
HWND CreateEx(HWND hWndParent, _U_RECT rect = NULL, LPCTSTR szWindowName = NULL, DWORD dwStyle = 0, DWORD dwExStyle = 0, LPVOID lpCreateParam = NULL)

Provided to prevent flickering during the creation of maximized MDI child windows. This is accomplished with setting the redraw flag of the mainframe window.

LRESULT OnCreate(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM lParam, BOOL& bHandled)

When the MDI child window is created maximized the MDI client window edge will be modified to avoid that both windows have the WS_EX_CLIENTEDGE style.

LRESULT OnGetIcon(UINT /*uMsg*/, WPARAM wParam, LPARAM /*lParam*/, BOOL& /*bHandled*/)

Loads the icon resource specified in the window class.

LRESULT OnWindowPosChanging(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM lParam, BOOL& bHandled)

Signals size changes to the CCommandBarCtrlImpl2 and sets the maximized flag in CMDIChildWinImplTraits2.

CMDIChildWinImplTraits2

static DWORD GetWndStyle(DWORD dwStyle)

Adds the WS_MAXIMIZE style if the maximized flag is set.