Поделиться через

Using Drop-Down Buttons in a Toolbar Control

  • Статья

In addition to standard push buttons, a toolbar can also have drop-down buttons. A drop-down button is usually indicated by the presence of an attached down arrow.

ПримечаниеПримечание.

The attached down arrow will appear only if the TBSTYLE_EX_DRAWDARROWS extended style has been set.

When the user clicks on this arrow (or the button itself, if no arrow is present), a TBN_DROPDOWN notification message is sent to the parent of the toolbar control. You can then handle this notification and display a pop-up menu; similar to the behavior of Internet Explorer.

The following procedure illustrates how to implement a drop-down toolbar button with a pop-up menu:

To implement a drop-down button

  1. Once your CToolBarCtrl object has been created, set the TBSTYLE_EX_DRAWDDARROWS style, using the following code:

    m_ToolBarCtrl.SetExtendedStyle(TBSTYLE_EX_DRAWDDARROWS);

  2. Set the TBSTYLE_DROPDOWN style for any new (InsertButton or AddButtons) or existing (SetButtonInfo) buttons that will be drop-down buttons. The following example demonstrates modifying an existing button in a CToolBarCtrl object:

    TBBUTTONINFO tbi;

tbi.dwMask = TBIF_STYLE;
tbi.cbSize = sizeof(TBBUTTONINFO);
m_ToolBarCtrl.GetButtonInfo(0, &tbi);
tbi.fsStyle |= TBSTYLE_DROPDOWN;
m_ToolBarCtrl.SetButtonInfo(0, &tbi);

  3. Add a TBN_DROPDOWN handler to the parent class of the toolbar object.

    ON_NOTIFY(TBN_DROPDOWN, IDC_TOOLBAR1, &CMyDialog::OnTbnDropDownToolBar1)

  4. In the new handler, display the appropriate popup menu. The following code demonstrates one method:

    void CMyDialog::OnTbnDropDownToolBar1(NMHDR* pNMHDR, LRESULT* pResult)
{
   LPNMTOOLBAR pToolBar = reinterpret_cast<LPNMTOOLBAR>(pNMHDR);
   ClientToScreen(&(pToolBar->rcButton)); // TrackPopupMenu uses screen coords

   CMenu menu;
   VERIFY(menu.LoadMenu(IDR_MENU1));
   CMenu* pPopup = menu.GetSubMenu(0);
   if (NULL != pPopup)
   {
      pPopup->TrackPopupMenu(TPM_LEFTALIGN | TPM_RIGHTBUTTON, 
         pToolBar->rcButton.left, pToolBar->rcButton.bottom, this);
   }

   *pResult = 0;
}

См. также

Основные понятия

Using CToolBarCtrl

Controls (MFC)