OnCommand 与OnCmdMsg

1、首先两者都是虚函数

CWnd::OnCommand，CCmdTarget::OnCmdMsg

2、看源码

 BOOL CWnd::OnCommand(WPARAM wParam, LPARAM lParam)
     // return TRUE if command invocation was attempted
 {
     UINT nID = LOWORD(wParam);
     HWND hWndCtrl = (HWND)lParam;
     int nCode = HIWORD(wParam);

     // default routing for command messages (through closure table)

     if (hWndCtrl == NULL)
     {
         // zero IDs for normal commands are not allowed
         if (nID == 0)
             return FALSE;

         // make sure command has not become disabled before routing
         CTestCmdUI state;
         state.m_nID = nID;
         OnCmdMsg(nID, CN_UPDATE_COMMAND_UI, &state, NULL);
         if (!state.m_bEnabled)
         {
             TRACE1("Warning: not executing disabled command %d\n", nID);
             return TRUE;
         }

         // menu or accelerator
         nCode = CN_COMMAND;
     }
     else
     {
         // control notification
         ASSERT(nID == 0 || ::IsWindow(hWndCtrl));

         if (_afxThreadState->m_hLockoutNotifyWindow == m_hWnd)
             return TRUE;        // locked out - ignore control notification

         // reflect notification to child window control
         if (ReflectLastMsg(hWndCtrl))
             return TRUE;    // eaten by child

         // zero IDs for normal commands are not allowed
         if (nID == 0)
             return FALSE;
     }

 #ifdef _DEBUG
     if (nCode < 0 && nCode != (int)0x8000)
         TRACE1("Implementation Warning: control notification = $%X.\n",
             nCode);
 #endif

     return OnCmdMsg(nID, nCode, NULL, NULL);
 }

其中：OnCommand中调用OnCmdMsg。

 BOOL CCmdTarget::OnCmdMsg(UINT nID, int nCode, void* pExtra,
     AFX_CMDHANDLERINFO* pHandlerInfo)
 {
 <span style="WHITE-SPACE: pre"> </span>// 省略
     return FALSE;   // not handled
 }

作用：

OnCmdMsg : 

Called by the framework to route and dispatch command messages and to handle the update of command user-interface objects. 

调用框架路由和调度命令消息和处理更新用户界面对象的命令。

OnCommand:   是响应WM_COMMAND消息

The framework calls this member function when the user selects an item from a menu, when a child control sends a notification message, or when an accelerator keystroke is translated. 

该框架调用该成员函数当用户选择一个项目从一个菜单,当一个孩子控制发送一个通知消息,或者当一个加速器击键是翻译。

 BOOL CToolTipDlg::OnCommand(WPARAM wParam, LPARAM lParam)
 {
     // TODO: Add your specialized code here and/or call the base class
     assert(wParam);

     switch(lParam)
     {
     case WM_RBUTTONDOWN:
         AfxGetApp()->m_pMainWnd->ShowWindow(SW_SHOW);
         break;
     }
     return CDialog::OnCommand(wParam, lParam);
 }

响应WM_COMMAND消息 做出相应 的处理

 

一个项目中使用的代码

BOOL CGameControl::OnCommand(WPARAM wParam, LPARAM lParam) 
{
 int id = LOWORD(wParam); //IDC_CONTROL_HALL+m_gameSerId.RoomID
 CMainFrame *pMainFrame = theApp.GetMainFrame();
 if(HIWORD(wParam)==BN_DOUBLECLICKED)
 {
  if(id == DLGBOTTOM_ID_ROOM)             // 按键ID
  {
   if(m_gameSerId.RoomID>0)
    pMainFrame->PostMessage(WM_GAME_CONTROL,ROOMSVR,1);
  }
 }
 return CDialog::OnCommand(wParam, lParam);

其中相关：

Message Source	wParam (high word)	wParam (low word)	lParam
Menu	0	Menu identifier (IDM_*)	0
Accelerator	1	Accelerator identifier (IDM_*)	0
Control	Control-defined notification code	Control identifier	Handle to the control window