We have a system (using ASP.NET C# 4.0) that supports Greek, Cyrillic, Chinese characters. But a third party system doesn't seem to work correctly. To avoid issues when entering data for this third party system, I want to limit the text fields to accept only English or accented characters, but return a validation error for other characters.
How can I accomplish this? It seems I can use a regex along the lines of \p{Latin}, but C# doesn't seem to support this from my experience, as I get an Unknown property 'Latin'
error.