MFC 将 CMFCToolBar 按钮更改为切换而不是按下/释放？

Question

I found an article online that said to setup the toolbar button to be a type that stays pressed you just set a style TBBS_CHECKBOX on the button but it doesn't work for me (it still acts like a normal button). I confirmed the style is set, just after created and the SetWindowText() MFC wizard setup of CMainFrame::OnCreate() . What am I doing wrong?

 for (int i=0; ; i++) {
    int id=m_wndToolBar.GetItemID(i);
    if (id==0) {
      break;
    }
    if (id == ID_THE_ID) {
      m_wndToolBar.SetButtonStyle(i, TBBS_CHECKBOX);
    }
  }

Answer 1

Using Command Handlers is the recommended implementation here. A command ID may be used in multiple UI items, eg a menu item and a toolbar button. A handler affects all items with the same ID, so you don't need a separate one for each item. The CCmdUI Class provides methods that can cause UI items like menus or toolbar buttons to behave as push-buttons, check-boxes or radio-buttons, in addition to enabling/disabling.

In your example, suppose that the option whether to filter is instantiated on a per document basis, ie all views of the document would be filtered or non-filtered, all at the same time. You should define a boolean variable in your document class:

BOOL m_bFilterData = FALSE;

Then the ON_COMMAND and ON_UPDATE_COMMAND_UI handlers for the toolbar button with the Filter pic (and possibly a menu item as well):

BEGIN_MESSAGE_MAP(CMyDoc, CDocument)
  .
  .
    ON_COMMAND(ID_VIEW_FILTERDATA, OnViewFilterData)
    ON_UPDATE_COMMAND_UI(ID_VIEW_FILTERDATA, OnUpdateViewFilterData)
  .
  .
END_MESSAGE_MAP()

void CMyDoc::OnViewFilterData()
{
    // Toggle filtered state
    m_bFilterData = !m_bFilterData;
    // Tell all views to refresh - You can limit this using the lHint/pHint params 
    UpdateAllViews(NULL, 0L, NULL);
}

void CMyDoc::OnUpdateViewFilterData(CCmdUI* pCmdUI)
{
    // Enable/Disable as needed
    pCmdUI->Enable(m_nTotalItems>0);
    // Show pressed/checked if data filtered
    pCmdUI->SetCheck(m_bFilterData);
}

Now, if the filter option is instantiated per view, ie each view can indpendently be filtered or non-filtered, the above must go to your view class(-es):

void CMyView::OnViewFilterData()
{
    // Toggle filtered state
    m_bFilterData = !m_bFilterData;
    // Refresh this view only
    .
    .
}

void CMyView::OnUpdateViewFilterData(CCmdUI* pCmdUI)
{
    // Enable/Disable as needed
    pCmdUI->Enable(GetDocument()->m_nTotalItems > 0);
    // Show pressed/checked if data filtered
    pCmdUI->SetCheck(m_bFilterData);
}