How can i use custom forms authentication or forms authentication with 3 fields in my web application

1] Create your member database with required fields (company id, user id, password, ....).


2] Create a login page with required 3 fields


3] On Login button click do the following.

  a] Fetch member details for the company id & user id
      If no data found,  throw error invalid company id, user id or password
  b] If Data found, Match the password (if hashed password is stored, hash the input password and match)

  if Everything is ok
 
 string userData = "";
                                bool isPersistent = false; // If you have remember me checkbox, set accordingly
                                string username = // UserId from in the input or from the fetched data


                                FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(1, username, DateTime.Now, DateTime.Now.AddMinutes(30), isPersistent, userData, FormsAuthentication.FormsCookiePath);


                                // Encrypt the ticket.
                                string encTicket = FormsAuthentication.Encrypt(ticket);


                                // Create the cookie.
                                Response.Cookies.Add(new HttpCookie(FormsAuthentication.FormsCookieName, encTicket));


Response.Redirect(FormsAuthentication.GetRedirectUrl(username, isPersistent));