public static extern int TrackPopupMenu(IntPtr hMenu, uint uFlags, int x, int y, int nReserved, IntPtr hWnd, ref RECT prcRect);

    Shared Function TrackPopupMenuEx( _

static extern bool TrackPopupMenuEx(IntPtr hmenu, uint fuFlags, int x, int y,

    Shared Function TrackPopupMenuEx( _

static extern uint TrackPopupMenuEx(IntPtr hMenu, uint uFlags, int x, int y, IntPtr hWnd, IntPtr tpmParams);

Use TrackPopupMenuEx with the TPM_RETURNCMD flag to return the ID of the selected Menu Item.

    uint menuItemID = TrackPopupMenuEx(hMenu, TPM_BOTTOMALIGN | TPM_RETURNCMD, Screen.PrimaryScreen.WorkingArea.Width, Screen.PrimaryScreen.WorkingArea.Height, eventSink.Hwnd, IntPtr.Zero);