private void Log(string s , Color? c = null)
        {
            TB_Log.SelectionStart = TB_Log.TextLength;
            TB_Log.SelectionLength = 0;
            TB_Log.SelectionColor = c ?? Color.Black;
            TB_Log.AppendText((TB_Log.Lines.Count() == 0 ? "" : Environment.NewLine) + DateTime.Now + "\t" + s);
            TB_Log.SelectionColor = Color.Black;

        }