Windows api programming-How to send/post messages to an application window to call up the menu items? - c++

Question

The problem
I have been working on a Windows cloud desktop project this week. One feature requires the server side can response to the users' inputs (mouse, keyboard...) from the client. I post the input messages (e.g., WM_LBUTTONDOWN, WM_KEYDOWN...) from the client to the specific application window in the server. Everything works fine when inputs target is the client area of an application window. However, the menu bar's item ("File" in notepad.exe, for example) does not response to the mouse clicking events. Here list part of my codes:
struct MouseMsg {
UINT msg;
WPARAM wParam;
LPARAM lParam;
};
enum class MouseEvent : unsigned int {
DOWN = 0,
UP,
MOVE,
WHEEL
};
struct MouseInputData
{
int32_t button;
int32_t wheel;
int32_t px;
int32_t py;
};
void ConstructMouseClickMsg(MouseMsg& mouseMsg, MouseInputData* mData, MouseEvent motion)
{
mouseMsg.lParam = MAKELPARAM(mData->px, mData->py);
switch (mData->button)
{
case 0:
{
mouseMsg.wParam = MK_LBUTTON;
mouseMsg.msg = (motion == MouseEvent::DOWN) ? WM_LBUTTONDOWN : WM_LBUTTONUP;
break;
}
case 1:
{
mouseMsg.wParam = MK_RBUTTON;
mouseMsg.msg = (motion == MouseEvent::DOWN) ? WM_RBUTTONDOWN : WM_RBUTTONUP;
break;
}
case 2:
{
mouseMsg.wParam = MK_MBUTTON;
mouseMsg.msg = (motion == MouseEvent::DOWN) ? WM_MBUTTONDOWN : WM_MBUTTONUP;
break;
}
default:
LOG->warn("Unknown mouse button types");
break;
}
}
void OnMouseClick(MouseInputData* mData, MouseEvent motion)
{
HWND mTargetHwnd = GetInputWindow(); // Omit details.
// This function can get the target window's handle
// and can tell if the window is client or menu (parent)
if (!mTargetHwnd)
{
LOG->warn("Null window");
return;
}
// construct mouse clicking messages
MouseMsg mouseMsg;
ConstructMouseClickMsg(mouseMsg, mData->button, motion);
if (mIsClientArea) // in client area or the menu bar? set in GetInputWindow()
{
PostMessageA(mTargetHwnd, mouseMsg.msg, mouseMsg.wParam, mouseMsg.lParam);
}
else
{
// How to ???
}
}
What I have tried
I used spy++ to monitor what messages a window received when the menu bar was clicked (as lines 1296~1327 in the following picture shows). WM_NCHITTEST, WM_NCLBUTTONDOWN, WM_SYSCOMMAND seemed to be the solution. I tried post all these messages but no response either.
Have-a-try codes:
if (mIsClientArea) // in client area or the menu bar? set in GetInputWindow()
{
PostMessageA(mTargetHwnd, mouseMsg.msg, mouseMsg.wParam, mouseMsg.lParam);
}
else
{
// How to ???
LOG->info("try to call up menu");
if (motion == MouseEvent::DOWN)
{
PostMessageA(mTargetHwnd, WM_NCLBUTTONDOWN, HTMENU, mouseMsg.lParam);
//PostMessageA(mCurrentHwnd, WM_SYSCOMMAND, SC_MOUSEMENU | 0x0005, mouseMsg.lParam);
}
else
{
PostMessageA(mTargetHwnd, WM_NCLBUTTONUP, HTMENU, mouseMsg.lParam);
}
}
Help!!!
Are there any specialist on Windows system can give me some hints please? Thanks sincerely!