private bool DoMatchesWord(NSString text, int location, int length, Regex word)
{
bool matches = false;
if (location >= 0 && location + length <= text.length())
{
string str;
text.getCharacters_range(new NSRange(location, length), out str);
Match match = word.Match(str);
matches = match.Success && match.Length == str.Length;
}
return matches;
}