Allow @ special character but not as first character

Question

I am doing UserId validation. I have added regex validation to allow numbers and characters in user id.

[RegularExpression(@"^[A-Za-z0-9]*$", ErrorMessage = "Only characters and digits are allowed")]

How can I allow the "@" symbol in Userid but not as the first character?

Answer 1

The following regex should see you through:

@"^[A-Za-z0-9]+[A-Za-z0-9@]*$"