public static void GetLineAndPosFromIndex(this TextBoxBase self, int index, out int line, out int pos) { line = self.GetLineFromCharIndex(index); int linepos = self.GetFirstCharIndexFromLine(line); pos = index - linepos; }
private static void DelLine(TextBoxBase rtb, int index) => rtb.Text = rtb.Text.Remove(rtb.GetFirstCharIndexFromLine(index) - 1, rtb.Lines[index].Length + 1);