private int userExists(string username)
 {
     LINQUserInformationDataContext ui = new LINQUserInformationDataContext();
     var count = (from p in ui.LoginInformations
                  where p.UserName == username
                  select p).Count();
     return count;
 }
        public bool UserExists(string username)
        {
            LINQUserInformationDataContext ui = new LINQUserInformationDataContext();
            var count = (from p in ui.LoginInformations
                         where p.UserName == username
                         select p).Count();

            if (count > 0)
                return true;
            return false;
        }
 public int login(string username, string password)
 {
     LINQUserInformationDataContext ui = new LINQUserInformationDataContext();
     IQueryable<int> count = (from p in ui.LoginInformations
                  where p.UserName == username && p.Password == password
                  select p.ID);
     
     foreach (int element in count)
     {
        return element;
     }
     return -1;
 }
 public bool CreateAccount(string username, string password)
 {
     if (userExists(username) != 0)
         return false;
     try
     {
         LINQUserInformationDataContext ui = new LINQUserInformationDataContext();
         LoginInformation li = new LoginInformation();
         {
             li.UserName = username;
             li.Password = password;                         
         };
         ui.LoginInformations.InsertOnSubmit(li);
         ui.SubmitChanges();
     }
     catch (Exception)
     {
         return false;
     }
     return true;
 }