Ytukyg

I have an issue in the Try Catch block of my code below.
In function SetUser, I use the getId function that returns an Id if the user exists in DB otherwise, I get a NullReferenceException.

I call this function in the try catch block in Login. I have a problem with the catch because when the exception is generated, I would like the user to be redirected to the register page. But when I try to execute my code with a non-existing user, I think that I have a kind of infinite loop because my page doesn't stop loading. I don't understand what I'm doing wrong. Need help please

function Login:

 public static void Login(HttpRequest Request, HttpResponse Response, string redirectUri)

{

    if (Request.IsAuthenticated)

        return;

    if (!Request.Form.AllKeys.Contains("id_token"))

        return;

    string value = Request.Form.Get("id_token");

    JObject id_token = JwtDecode(value);

    string upn = id_token.GetValue("upn").ToString();

    DateTime expiretime = GetExpireTime(id_token);



    try

    {

        SetUser(id_token);

    }

    catch (Exception ex)

    {

        Response.Redirect("~/register.aspx");

    }

    FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(1, upn, DateTime.UtcNow, expiretime, false, id_token.ToString(), FormsAuthentication.FormsCookiePath);

    string encryptedcookie = FormsAuthentication.Encrypt(ticket);

    HttpCookie cookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedcookie);

    cookie.Expires = expiretime;

    Response.Cookies.Add(cookie);

    redirectUri = GetRedirectUrl(Request, redirectUri);

    Response.Redirect(redirectUri, true);

}

function setUser:

 private static void SetUser(JObject id_token)

{

    string email = id_token.GetValue("unique_name").ToString();

    string name = id_token.GetValue("given_name").ToString();

    DataSet ds;



    List<Claim> claims = new List<Claim>()

    {

        new Claim(ClaimTypes.Email, email),

        new Claim(ClaimTypes.Name, GetId(email))

    };



    string roles= "SELECT name FROM AspNetRoles;

    ds = GetDataSet(roles);



    if (ds.Tables.Count > 0)

    {

        foreach (var row in ds.Tables(0).Rows)

            claims.Add(new Claim(ClaimTypes.Role, row("name")));

    }



    ClaimsIdentity claimsIdentity = new ClaimsIdentity(claims, "Cookies");

    ClaimsPrincipal principal = new ClaimsPrincipal(claimsIdentity);

    HttpContext.Current.GetOwinContext().Authentication.User = principal;

    Thread.CurrentPrincipal = principal;

}

function getId:

 public static string getId(string email)

{

    return ((new UserManager()).FindByEmail(email)).Id;

}