}//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
