Which characters are allowed in hashtags
问题 I am having a really hard time figuring out a regular expression (in C#) to validate hashtags. \w simply isn't enough as special characters are missing (ä, ö, ø, æ, å for starters, but also a lot of other foreign characters. I need to support ALL hashtags there is. Mainly from Twitter, but in the future also from other providers. My best shot (so far) is: ^#[a-zA-Z_0-9\u00C0-\u02AF]+$ (C# regex) I cannot find any decent documentation from Twitter or anyone else about this, so: Does anyone