Regular expression to restrict Extended ASCII character set

Question

I have multi lingual application which creates xml files but Extended ASCII characters from 168 to 254 (¿⌐¬½¼¡«»░▓│┤╡╢╖╕╣║╗╜╛┐└┴┬├) are not supposed in XML tags so, I would like

Answer 1

Second option was to create a string of all symbols from 168 to 254 and check if string contains any of them but not sure if it is reliable and accurate solution.

Yes, this is a reliable and accurate solution. It is also more lightweight than regular expressions.