BetterMembership.Web.BetterMembershipProvider.ValidateUserName C# (CSharp) Method

        private bool ValidateUserName(string username)
        {
            if (string.IsNullOrWhiteSpace(username))
            {
                return false;
            }

            if (username.Contains("@") && this.AllowEmailAsUserName)
            {
                return this.ValidateEmail(username, true, this.MaxUserNameLength);
            }

            if (username.Length > this.MaxUserNameLength)
            {
                return false;
            }

            if (this.UserNameRegularExpression.Length > 0)
            {
                if (!Regex.IsMatch(username, this.UserNameRegularExpression))
                {
                    return false;
                }
            }

            return true;
        }
    }