C++窗口內(nèi)置的滾動(dòng)條繪制方法?

大家覺得應(yīng)該怎么繪制呢？
    PS:不能通過新建窗口替換的方法
    case WM_MOVE:
    case WM_PAINT:
    case WM_NCPAINT:
    case WM_NCACTIVATE:
    case WM_NOTIFY:
    case WM_NCLBUTTONUP:case WM_NCLBUTTONDOWN:
    case WM_NCRBUTTONDOWN: case WM_NCRBUTTONUP:
    case WM_NCMBUTTONDOWN: case WM_NCMBUTTONUP:
    case WM_NCLBUTTONDBLCLK:case WM_NCMOUSEMOVE: