Constants VK_LBUTTON (01) Left mouse button VK_RBUTTON (02) Right mouse button VK_CANCEL (03) Control-break processing VK_MBUTTON (04) Middle mouse button (three-button mouse) VK_XBUTTON1 (05) Windows 2000/XP: X1 mouse button VK_XBUTTON2 (06) Windows 2000/XP: X2 mouse button - (07) Undefined VK_BACK (08) BACKSPACE key VK_TAB (09) TAB key - (0A-0B) Reserved VK_CLEAR (0C) CLEAR key VK_RETURN (0D) ..