Notes about Regex::IsMatch if (!System::Text::RegularExpressions::Regex::IsMatch (this->MyString->Text, “[0-9a-fA-f]{1,3}” )) MessageBox::Show ( “Invalid value” ); The problem with the above expression is that it doesn’t match what it should. There are 2 special characters, ^ and $ which specify the beginning and the end of the string to match. The way you used it, it matches any […]