public static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wParam, [In, Out] NativeMethods.HDITEM lParam);
internal static bool Header_SetItem(IntPtr hWndHeader, int index, [In, Out] NativeMethods.HDITEM hdi) { IntPtr success = SendMessage(hWndHeader, HDM_SETITEM, new IntPtr(index), hdi); return((success != IntPtr.Zero) ? true : false); }