S.Kuskov, все чуть-чуть не так. При проверке используеся функция IsWellFormedUriString. И "By default, the string is considered well-formed in accordance with RFC 2396 and RFC 2732. If International Resource Identifiers (IRIs) or Internationalized Domain Name (IDN) parsing is enabled, the string is considered well-formed in accordance with RFC 3986 and RFC 3987". То есть, вроде как, на самом деле функция уже умеет проверять кириллические (IDN) домены. Но by default эта возможность выключена.
http://msdn.microsoft.com/en-us/libr...uristring.aspx
Цитата:
Enabling IDN will convert all Unicode labels in a domain name to their Punycode equivalents. Punycode names contain only ASCII characters and always start with the xn-- prefix. The reason for this is to support existing DNS servers on the Internet, since most DNS servers only support ASCII characters (see RFC 3940).
http://msdn.microsoft.com/ru-ru/libr...ewDropDownText