System.Windows.Forms.CommandBar.NotifyCustomDrawToolBar C# (CSharp) Method

        private void NotifyCustomDrawToolBar(ref Message m)
        {
            m.Result = (IntPtr) NativeMethods.CDRF_DODEFAULT;

            NativeMethods.DLLVERSIONINFO dvi = new NativeMethods.DLLVERSIONINFO();
            dvi.cbSize = Marshal.SizeOf(typeof(NativeMethods.DLLVERSIONINFO));
            NativeMethods.DllGetVersion(ref dvi);
            if (dvi.dwMajorVersion < 6)
            {
                NativeMethods.LPNMTBCUSTOMDRAW tbcd = (NativeMethods.LPNMTBCUSTOMDRAW)m.GetLParam(typeof(NativeMethods.LPNMTBCUSTOMDRAW));
                NativeMethods.RECT rc = tbcd.nmcd.rc;

                Rectangle rectangle = new Rectangle(rc.left, rc.top, rc.right - rc.left, rc.bottom - rc.top);

                Graphics graphics = Graphics.FromHdc(tbcd.nmcd.hdc);
                CommandBarItem item = items[tbcd.nmcd.dwItemSpec];

                bool hot = ((tbcd.nmcd.uItemState & NativeMethods.CDIS_HOT) != 0);
                bool selected = ((tbcd.nmcd.uItemState & NativeMethods.CDIS_SELECTED) != 0);
                bool disabled = ((tbcd.nmcd.uItemState & NativeMethods.CDIS_DISABLED) != 0);

                CommandBarCheckBox checkBox = item as CommandBarCheckBox;
                if ((checkBox != null) && (checkBox.IsChecked))
                {
                    ControlPaint.DrawBorder3D(graphics, rectangle, Border3DStyle.SunkenOuter);
                }
                else if (selected)
                {
                    ControlPaint.DrawBorder3D(graphics, rectangle, Border3DStyle.SunkenOuter);
                }
                else if (hot)
                {
                    ControlPaint.DrawBorder3D(graphics, rectangle, Border3DStyle.RaisedInner);
                }

                Image image = item.Image;
                if (image != null)
                {
                    Size size = image.Size;
                    Point point = new Point(rc.left + ((rc.right - rc.left - size.Width) / 2), rc.top + ((rc.bottom - rc.top - size.Height) / 2));
                    NativeMethods.DrawImage(graphics, image, point, disabled);
                }

                m.Result = (IntPtr)NativeMethods.CDRF_SKIPDEFAULT;
            }
        }