}//method private bool DoSearch(ITextBox textBox, string fragment, int start) { textBox.SelectionLength = 0; // Compile the regular expression. Regex r = new Regex(fragment, RegexOptions.IgnoreCase); // Match the regular expression pattern against a text string. Match m = r.Match(textBox.Text.Substring(start)); if (m.Success) { int i = 0; Group g = m.Groups[i]; CaptureCollection cc = g.Captures; Capture c = cc[0]; textBox.SelectionStart = c.Index + start; textBox.SelectionLength = c.Length; textBox.Focus(); textBox.ScrollToCaret(); return true; } return false; }//method