FastColoredTextBoxNS.InsertTextCommand.InsertText C# (CSharp) Method

        internal static void InsertText(string insertedText, TextSource ts)
        {
            var tb = ts.CurrentTB;
            try
            {
                tb.Selection.BeginUpdate();
                char cc = '\x0';

                if (ts.Count == 0)
                {
                    InsertCharCommand.InsertLine(ts);
                    tb.Selection.Start = Place.Empty;
                }
                tb.ExpandBlock(tb.Selection.Start.iLine);
                var len = insertedText.Length;
                for (int i = 0; i < len; i++)
                {
                    var c = insertedText[i];
                    if(c == '\r' && (i >= len - 1 || insertedText[i + 1] != '\n'))
                        InsertCharCommand.InsertChar('\n', ref cc, ts);
                    else
                        InsertCharCommand.InsertChar(c, ref cc, ts);
                }
                ts.NeedRecalc(new TextSource.TextChangedEventArgs(0, 1));
            }
            finally {
                tb.Selection.EndUpdate();
            }
        }

        /// <summary>
        /// Execute operation
        /// </summary>
        public override void Execute()
        {
            var tb = ts.CurrentTB;

            prevText.Clear();

            ts.OnTextChanging(ref insertedText);

            tb.Selection.BeginUpdate();
            tb.BeginUpdate();
            for (int i = ranges.Count - 1; i >= 0; i--)
            {
                tb.Selection.Start = ranges[i].Start;
                tb.Selection.End   = ranges[i].End;
                prevText.Add(tb.Selection.Text);
                ClearSelected(ts);
                if (insertedText != "")
                {
                    InsertTextCommand.InsertText(insertedText, ts);
                }
            }
            if (ranges.Count > 0)
            {
                ts.OnTextChanged(ranges[0].Start.iLine, ranges[ranges.Count - 1].End.iLine);
            }
            tb.EndUpdate();
            tb.Selection.EndUpdate();
            ts.NeedRecalc(new TextSource.TextChangedEventArgs(0, 1));

            lastSel = new RangeInfo(tb.Selection);
        }