string patten = "\\<table\\>(.*)\\</table\\>";
Regex re = new Regex(patten, RegexOptions.IgnoreCase & RegexOptions.Multiline & RegexOptions.CultureInvariant);
string test = "<table><tr><td><table><tr><td>Hello</td></tr></table></td></tr></table>";
Match m = re.Match(test);
Console.WriteLine("Input: {0}", test);
while (m.Groups.Count == 2)
{
if (re.IsMatch(m.Groups[1].Value))
{
m = re.Match(m.Groups[1].Value);
}
else
{
break;
}
}
Console.WriteLine("Last Find: {0}", m.Value);