try
        {
            SqlConnection conn = new SqlConnection("Server=.; Database=LoginDatabase; Trusted_Connection=True;");
            conn.Open();
            SqlCommand cmd = new SqlCommand("select Passhash, UserID, Username from Userdata where Username=@Username", conn);
            cmd.Parameters.AddWithValue("@UserName", Uname.Text);
            SqlDataReader reader = cmd.ExecuteReader();
            reader.Read();
            string sHash = (string)reader[0];
            int UserID = (Int32)reader[1];
            string Username = (string)reader[2];
            reader.Close();
            if (BCrypt.Net.BCrypt.Verify(Pword.Text, sHash))
            {
                if (BCrypt.Net.BCrypt.PasswordNeedsRehash(sHash, 13))
                {
                    SqlCommand update = new SqlCommand("Update Userdata set Passhash=@PHash Where Username=@Username", conn);
                    update.Parameters.AddWithValue("@UserName", Uname.Text);
                    update.Parameters.AddWithValue("@PHash", BCrypt.Net.BCrypt.HashPassword(Uname.Text, 13));
                    update.ExecuteNonQuery();
                }
                Session["FirstName"] = Username;
                Session["UserID"] = UserID;
                HttpContext.Current.Response.Redirect("LoggedIn.aspx");
            }
            else
            {
                ClientScript.RegisterStartupScript(Page.GetType(), "validation", "<script language ='javascript'>alert('Invalid Username and/or Passowrd')</script>");
            }
        }
        catch
        {
            ClientScript.RegisterStartupScript(Page.GetType(), "validation", "<script language ='javascript'>alert('Invalid Username and/or Passowrd')</script>");
        }
        finally
        {
            conn.Close();
        }
    }
}