SendMessage发送命令右击桌面指定位置无效,该如何解决

SendMessage发送命令右击桌面指定位置无效
Private   Declare   Function   SendMessage&   Lib   "user32 "   Alias   "SendMessageA "   (ByVal   hwnd   As   Long,   ByVal   wMsg   As   Long,   ByVal   wParam   As   Long,   lParam   As   Any)

Private   Const   WM_RBUTTONDOWN   As   Long   =   &H204
Private   Const   WM_RBUTTONUP   As   Long   =   &H205


    Dim   lParam   As   Long
    lParam   =   y   *   &H10000   Or   x
    SendMessage   hWndTarget,   WM_RBUTTONDOWN,   0,   lParam
    SendMessage   hWndTarget,   WM_RBUTTONUP,   0,   lParam

如下  
跪求答案

[解决办法]
lParam = y * &H10000 Or x

这个有这么定义的吗？