为工具栏按钮增加下拉菜单

 

If you wanted to add a drop menu like the ones seen in internet explorer, it is pretty straight forward. This approach for will work for both Visual C++ 5 and 6, however you may want to read up on the enhancements to the toolbar class for VC 6.0.

First off, after your toolbar has been created in CMainFrame::OnCreate(), you will need to make a call to the following method:

	m_wndToolBar.GetToolBarCtrl().SetExtendedStyle(TBSTYLE_EX_DRAWDDARROWS);

This will enable your toolbar to handle drop arrows. The next thing you will need to do, is to actually add the drop arrow to your desired button. This will be done via the SetButtonStyle() method:

	DWORD dwStyle = m_wndToolBar.GetButtonStyle(m_wndToolBar.CommandToIndex(ID_FILE_OPEN));
	dwStyle |= TBSTYLE_DROPDOWN;
	m_wndToolBar.SetButtonStyle(m_wndToolBar.CommandToIndex(ID_FILE_OPEN), dwStyle);

Now, you will need to add a message handler for the drop arrow, as well a menu to the application resources. Assuming you already know how to create a menu, ( if not, click on the resource tab, select the resource name ie: MyApp Resources, then right click. Select insert, then select Menu, then press the New button ) and assuming that the resource id for our menu is IDR_MENU1, add the following code to CMainFrame's message map:

BEGIN_MESSAGE_MAP(CMainFrame, CMDIFrameWnd)
	//{{AFX_MSG_MAP(CMainFrame)
	...
	ON_NOTIFY(TBN_DROPDOWN, AFX_IDW_TOOLBAR, OnToolbarDropDown)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

Add the following method to CMainFrame's .cpp file:

void CMainFrame::OnToolbarDropDown(NMTOOLBAR* pnmtb, LRESULT *plr)
{
	CWnd *pWnd;
	UINT nID;

	// Switch on button command id's.
	switch (pnmtb->iItem)
	{
	case ID_FILE_OPEN:
		pWnd = &m_wndToolBar;
		nID  = IDR_MENU1;
		break;
	default:
		return;
	}

	// load and display popup menu
	CMenu menu;
	menu.LoadMenu(nID);
	CMenu* pPopup = menu.GetSubMenu(0);
	ASSERT(pPopup);

	CRect rc;
	pWnd->SendMessage(TB_GETRECT, pnmtb->iItem, (LPARAM)&rc);
	pWnd->ClientToScreen(&rc);

	pPopup->TrackPopupMenu( TPM_LEFTALIGN | TPM_LEFTBUTTON | TPM_VERTICAL,
		rc.left, rc.bottom, this, &rc);
}

Then add the following to CMainFrame's .h file:

	//{{AFX_MSG(CMainFrame)
	...
	afx_msg void OnToolbarDropDown(NMTOOLBAR* pnmh, LRESULT* plRes);
	//}}AFX_MSG