ZForge.Controls.HeaderPanel.WmNCCalcSize C# (CSharp) Method

        private void WmNCCalcSize(ref Message m)
        {
            if (m.WParam == HeaderPanelNativeMethods.FALSE)
            {
                HeaderPanelNativeMethods.RECT ncRect = (HeaderPanelNativeMethods.RECT)m.GetLParam(typeof(HeaderPanelNativeMethods.RECT));
                Rectangle proposed = ncRect.Rect;
                RecalcNonClientArea(ref proposed);
                ncRect = HeaderPanelNativeMethods.RECT.FromRectangle(proposed);
                Marshal.StructureToPtr(ncRect, m.LParam, false);
            }
            else if (m.WParam == HeaderPanelNativeMethods.TRUE)
            {
                HeaderPanelNativeMethods.NCCALCSIZE_PARAMS ncParams =
                        (HeaderPanelNativeMethods.NCCALCSIZE_PARAMS)m.GetLParam(typeof(HeaderPanelNativeMethods.NCCALCSIZE_PARAMS));
                Rectangle proposed = ncParams.rectProposed.Rect;
                RecalcNonClientArea(ref proposed);
                ncParams.rectProposed = HeaderPanelNativeMethods.RECT.FromRectangle(proposed);
                Marshal.StructureToPtr(ncParams, m.LParam, false);
            }
            m.Result = IntPtr.Zero;
        }