上下文菜单与TrackPopupMenu

最新推荐文章于 2023-04-26 17:37:04 发布

原创最新推荐文章于 2023-04-26 17:37:04 发布 · 2.6k 阅读

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CC 4.0 BY-SA版权

文章标签：

#command #null #menu #class #ui #delete

本文通过一个简单的MFC应用程序示例介绍了如何在Windows应用程序中实现上下文菜单功能，并对比了从CWnd和CFrameWnd派生窗口类时ON_UPDATE_COMMAND_UI_RANGE宏的行为差异。

这算是一个演示程序吧，想不到上下文菜单也是采用ON_COMMAND宏来进行消息映射，在这里，我发现一个问题：从CWnd派生的类ON_UPDATE_COMMAND_UI_RANGE似乎没有效果，不知道应该再加点什么，但是从CFrameWnd派生出来问题就不会发生，真是奇怪……

看看从CWnd派生出来的效果：

contextMenuDemo.h

#pragma once class CMyApp : public CWinApp { virtual BOOL InitInstance(); }; class CMainWindow : public CWnd { public: CMainWindow(); protected: int m_nShape; void PostNcDestroy(); int OnCreate(LPCREATESTRUCT lpCreateStruct); void OnPaint(); void OnContextMenu(CWnd* pWnd, CPoint point); void OnShape(UINT nID); void OnUpdateShape(CCmdUI* pCmdUI); DECLARE_MESSAGE_MAP() };

contextMenuDemo.cpp:

#include <afxwin.h> #include "contextMenuDemo.h" #include "resource.h" CMyApp myApp; BOOL CMyApp::InitInstance() { m_pMainWnd = new CMainWindow; m_pMainWnd->ShowWindow(m_nCmdShow); m_pMainWnd->UpdateWindow(); return TRUE; } BEGIN_MESSAGE_MAP(CMainWindow, CWnd) ON_WM_CREATE() ON_WM_PAINT() ON_WM_CONTEXTMENU() ON_COMMAND_RANGE(ID_SHAPE_RECT, ID_SHAPE_CIRCLE, OnShape) ON_UPDATE_COMMAND_UI_RANGE(ID_SHAPE_RECT, ID_SHAPE_CIRCLE, OnUpdateShape) END_MESSAGE_MAP() CMainWindow::CMainWindow() { CString strWndClass = AfxRegisterWndClass(0, AfxGetApp()->LoadStandardCursor(IDC_ARROW), (HBRUSH)(COLOR_WINDOW + 1), AfxGetApp()->LoadStandardIcon(IDI_WINLOGO)); CreateEx(0, strWndClass, _T("玩玩了"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL); m_nShape = ID_SHAPE_RECT; } void CMainWindow::PostNcDestroy() { delete this; } int CMainWindow::OnCreate(LPCREATESTRUCT lpCreateStruct) { if(CWnd::OnCreate(lpCreateStruct) == -1) return -1; return 0; } void CMainWindow::OnContextMenu(CWnd* pWnd, CPoint point) { CMenu menu; menu.LoadMenu(IDR_MENU1); CPoint pt = point; ScreenToClient(&pt); CRect rc; GetClientRect(&rc); CMenu* pMenu = menu.GetSubMenu(0); if(rc.PtInRect(pt)) { pMenu->TrackPopupMenu(TPM_LEFTALIGN | TPM_RIGHTBUTTON, point.x, point.y, AfxGetMainWnd()); return; } CWnd::OnContextMenu(pWnd, point); } void CMainWindow::OnShape(UINT nID) { m_nShape = nID; Invalidate(); } void CMainWindow::OnPaint() { CPaintDC dc(this); switch(m_nShape) { case ID_SHAPE_RECT: dc.Rectangle(100, 100, 500, 500); break; case ID_SHAPE_CIRCLE: dc.Ellipse(100, 100, 500, 500); break; } } void CMainWindow::OnUpdateShape(CCmdUI* pCmdUI) { pCmdUI->SetCheck(pCmdUI->m_nID == m_nShape); }

运行效果没有太大的问题，就是SetCheck没有效果……

我们从CFrameWnd派生出来的话，问题就好了：

头文件： #pragma once class CMyApp : public CWinApp { virtual BOOL InitInstance(); }; class CMainWindow : public CFrameWnd { public: CMainWindow(); protected: int m_nShape; //void PostNcDestroy(); //int OnCreate(LPCREATESTRUCT lpCreateStruct); void OnPaint(); void OnContextMenu(CWnd* pWnd, CPoint point); void OnShape(UINT nID); void OnUpdateShape(CCmdUI* pCmdUI); DECLARE_MESSAGE_MAP() }; 实现文件： #include <afxwin.h> #include "contextMenuDemo.h" #include "resource.h" CMyApp myApp; BOOL CMyApp::InitInstance() { m_pMainWnd = new CMainWindow; m_pMainWnd->ShowWindow(m_nCmdShow); m_pMainWnd->UpdateWindow(); return TRUE; } BEGIN_MESSAGE_MAP(CMainWindow, CFrameWnd) ON_WM_CREATE() ON_WM_PAINT() ON_WM_CONTEXTMENU() ON_COMMAND_RANGE(ID_SHAPE_RECT, ID_SHAPE_CIRCLE, OnShape) ON_UPDATE_COMMAND_UI_RANGE(ID_SHAPE_RECT, ID_SHAPE_CIRCLE, OnUpdateShape) END_MESSAGE_MAP() CMainWindow::CMainWindow() { Create(NULL, _T("玩玩")); m_nShape = ID_SHAPE_RECT; } void CMainWindow::OnContextMenu(CWnd* pWnd, CPoint point) { CMenu menu; menu.LoadMenu(IDR_MENU1); CPoint pt = point; ScreenToClient(&pt); CRect rc; GetClientRect(&rc); CMenu* pMenu = menu.GetSubMenu(0); if(rc.PtInRect(pt)) { pMenu->TrackPopupMenu(TPM_LEFTALIGN | TPM_RIGHTBUTTON, point.x, point.y, AfxGetMainWnd()); return; } CWnd::OnContextMenu(pWnd, point); } void CMainWindow::OnShape(UINT nID) { m_nShape = nID; Invalidate(); } void CMainWindow::OnPaint() { CPaintDC dc(this); switch(m_nShape) { case ID_SHAPE_RECT: dc.Rectangle(100, 100, 500, 500); break; case ID_SHAPE_CIRCLE: dc.Ellipse(100, 100, 500, 500); break; } } void CMainWindow::OnUpdateShape(CCmdUI* pCmdUI) { pCmdUI->SetCheck(pCmdUI->m_nID == m_nShape); }