Question

I have a problem, when I try to save new User in database. My code:

if (!user.ValidateUser(username, password))
{
    using (var session = NHibernateHelper.OpenSession())
    {
        User u = new User();
        u.Name = username;
        u.Email = string.Empty;
        u.Password = "123456";
        using (var transact = session.Transaction)
        {
            session.SaveOrUpdate(u); // I have an exception in this line
            transact.Commit();
        }
    }
}

Error:

Collection cannot be null. Parameter name: c

How to save new user in database?

P.S. session.Save(user1); get me this exception too.

Update: User class

public partial class User
{
    public User()
    {
        this.CurrentTestings = new HashSet<CurrentTesting>();
        this.ResultsSet = new HashSet<ResultTesting>();
    }

    public virtual int Id { get; set; }
    public virtual string Name { get; set; }
    public virtual string Password { get; set; }
    public virtual string Email { get; set; }

    public virtual ICollection<CurrentTesting> CurrentTestings { get; set; }
    public virtual ICollection<ResultTesting> ResultsSet { get; set; }
}

Answer 1

Maybe class “User” has some references, for example:

class User
{
  IList<T> T;
}

Try to initialize this field with constractor:

class User
{
  public User
  {
    T = new List<T>();
  }
  IList<T> T;
}