问属性导致Stackoverflow异常

EN

public List<User> CreatUsers()
{
    List<User> users = new List<User>;

    //Some DB call to get a list of users
    foreach (var record in userlist)
        List.Add(CreatUser(record));
}

public User CreateUser(?? record)
{
    User user = new User();
    //Set properties
    if (record has creator) //pseudo-code
        user.Creator = CreatUser(record.Creator); //guessing as to record.Creator
}

public class User
{
    public User()
    {
        UserName = "";          //Stackoverflow on this line.
        EmailAddress = "";
    }

    public String UserName { get; set; }
    public String EmailAddress { get; set; }

    public User Creator { get; set; }
}
//{Cannot evaluate expression because the current thread is in a stack overflow state.}

public string UserName
{
    get { return UserName; }
    set { UserName = value; }
}

private string _UserName;
public string UserName
{
    get { return _UserName; }
    set { _UserName = value; }
}