如何以编程方式显示功能区按钮的下拉菜单？

Question

我具有功能区按钮，并添加了一组子项目。当用户单击按钮下方的小箭头时，将显示此类项目。我想在单击按钮本身时显示这样的下拉菜单。我该怎么办？

我最初的想法是当用户单击按钮时以编程方式显示菜单。我已经能够在工具栏（here）上执行相同的操作，但是在功能区上使用类似的解决方案会产生无限递归：

// ...
ON_COMMAND(ID_RIBBON_BUTTON, &MainFrame::OnButtonClicked)
// ...

CMFCRibbonPanel *panel = /* initialization */
CMFCRibbonButton *button = new CMFCRibbonButton(ID_RIBBON_BUTTON, "Caption");
panel->Add(button);

CMFCRibbonButton *item1 = new CMFCRibbonButton(ID_RIBBON_BUTTON, "Item 1");
button->AddSubItem(item1);
CMFCRibbonButton *item2 = new CMFCRibbonButton(ID_RIBBON_BUTTON, "Item 2");
button->AddSubItem(item2);

// ...
void MainFrame::OnButtonClicked()
{
  if (auto button = static_cast<CMFCRibbonButton *>(m_ribbons.wndRibbonBar.FindByID(ID_RIBBON_BUTTON))) {

    // button->OnClick({}); // <- causes infinite recursion

    // What to do here?
  }
}

Answer 1

到目前为止，我发现的最简单的方法是使用受保护的方法CMFCRibbonButton::OnShowPopupMenu。它意味着派生CMFCRibbonButton类并更改方法的可见性：

#include <afxribbonbutton.h>

class CMyMFCRibbonButton : public CMFCRibbonButton {
public:
  using CMFCRibbonButton::CMFCRibbonButton;

  virtual void OnShowPopupMenu() override {
    CMFCRibbonButton::OnShowPopupMenu();
  }
};

// ...
ON_COMMAND(ID_RIBBON_BUTTON, &MainFrame::OnButtonClicked)
// ...

CMFCRibbonPanel *panel = /* initialization */
CMyMFCRibbonButton *button = new CMyMFCRibbonButton(ID_RIBBON_BUTTON, "Caption");
panel->Add(button);

CMFCRibbonButton *item1 = new CMFCRibbonButton(ID_RIBBON_BUTTON, "Item 1");
button->AddSubItem(item1);
CMFCRibbonButton *item2 = new CMFCRibbonButton(ID_RIBBON_BUTTON, "Item 2");
button->AddSubItem(item2);

// ...
void MainFrame::OnButtonClicked()
{
  if (auto button = static_cast<CMyMFCRibbonButton*>(m_ribbons.wndRibbonBar.FindByID(ID_RIBBON_BUTTON))) {
    button->OnShowPopupMenu();
  }
}