After server hours, I found a way to do it.
Code:while(GetMessage(&Msg, NULL, 0, 0) > 0) { if (Msg.message == WM_KEYDOWN && Msg.wParam == VK_RETURN) { if (GetFocus() == hEdit1) MessageBox(hwnd, "It worked", It worked", MB_OK); } TranslateMessage(&Msg); DispatchMessage(&Msg); } return Msg.wParam;