App.Services.FormsAuthenticationService.SignIn C# (CSharp) Method

        public void SignIn(string userName, bool createPersistentCookie)
        {
            if (String.IsNullOrEmpty(userName))
            {
                throw new ArgumentException("Value cannot be null or empty.", "userName");
            }

            FormsAuthentication.SetAuthCookie(userName, createPersistentCookie);
        }