private void SetHScroll(SyncTextBox toSync, int value) { var wParam = new Win32.WParam((int)Win32.ScrollBarCommands.SB_THUMBPOSITION, value); var msg = new Message(); msg.HWnd = toSync.Handle; msg.Msg = Win32.WM_HSCROLL; msg.WParam = (IntPtr)wParam.Ptr(); msg.LParam = (IntPtr)0; toSync.WndProc(ref msg); }