MFC程序隐藏到托盘后显示解决思路

MFC程序隐藏到托盘后显示
刚学MFC，写了一个最小化到系统托盘的MFC程序，托盘中菜单想显示“打开”和“退出”两项，“打开”相关函数是用的自定义消息，最后点击退出有效而打开却无效，怎样才能点击“打开”让隐藏的对话框显示，谢谢了！

C/C++ code

LRESULT CAaaaaaaaaaDlg::OnShowTask(WPARAM wParam,LPARAM lParam){    if(wParam != IDR_MAINFRAME)     return 1;    switch(lParam)     {         case WM_RBUTTONUP:         {             LPPOINT lpoint = new tagPOINT;             ::GetCursorPos(lpoint);             CMenu menu;            menu.CreatePopupMenu();             menu.AppendMenu(MF_STRING, WM_OUT, "打开");            menu.AppendMenu(MF_STRING,  WM_DESTROY, "退出");            menu.TrackPopupMenu(TPM_LEFTALIGN, lpoint->x ,lpoint->y, this);            HMENU hmenu = menu.Detach();             menu.DestroyMenu();            delete lpoint;        }         break;         case WM_LBUTTONDBLCLK:         {             this->ShowWindow(SW_SHOWNORMAL);             this->SetForegroundWindow();         }        break;    }    return 0;}

C/C++ code

void CAaaaaaaaaaDlg::onOut(){    ShowWindow(SW_SHOWNORMAL);    SetForegroundWindow();}