VC中为工具栏创建下拉式按扭

实现步骤:

1、toolbar在CMainFrame::OnCreate()中被创建之后，扩展Toolbar的样式使其能够映射箭头按钮的消息。

DWORD dwExStyle = TBSTYLE_EX_DRAWDDARROWS;

m_wndToolBar.GetToolBarCtrl().SendMessage(TB_SETEXTENDEDSTYLE, 0, (LPARAM)dwExStyle);

2、将箭头加到指定的按钮中，通过SetButtonStyle()方法实现：

DWORD dwStyle = m_wndToolBar.GetButtonStyle(m_wndToolBar.CommandToIndex(ID_SEL_MODE));

dwStyle |= TBSTYLE_DROPDOWN;

m_wndToolBar.SetButtonStyle(m_wndToolBar.CommandToIndex(ID_SEL_MODE), dwStyle);

m_wndToolBar.SetButtonStyle(m_wndToolBar.CommandToIndex(ID_VIEW_MODE), dwStyle);

3、加入箭头按钮的消息映射：

BEGIN_MESSAGE_MAP(CMainFrame, CMDIFrameWnd)

ON_NOTIFY(TBN_DROPDOWN, AFX_IDW_TOOLBAR, OnToolbarDropDown)

END_MESSAGE_MAP()

声明消息响应函数

protected:

afx_msg void OnToolbarDropDown(NMTOOLBAR* pnmh, LRESULT* plRes);

消息响应函数：

void CMainFrame::OnToolbarDropDown(NMTOOLBAR* pnmtb, LRESULT *plr)

{

CWnd *pWnd;

UINT nID;

// Switch on button command id's.

switch (pnmtb->iItem)

{

case ID_SEL_MODE:

pWnd = &m_wndToolBar;

nID = IDR_SEL_MODE;

break;

case ID_VIEW_MODE:

pWnd = &m_wndToolBar;

nID = IDR_VIEW_MODE;

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);

}