C# asp.net mvc Username regex

Question

Im looking for regex for usernames

I want to allow:

• only ASCII
• only - _ symbols
• minium 5 characters and maximum 15

Answer 1

Here you go

^[-0-9A-Za-z_]{5,15}$

Note that the - is put first in the character class otherwise it will get the meaning of indicating a range as in 0-9 = 0 to 9