Question

I have a config data from a DHCP server that I put into classes like this:

public class DHCP
{
    public DHCP()
    {
        this.Scopes = new List<Scope>();
    }

    public List<Scope> Scopes;

    public class Scope
    {
        public Scope(string ScopeAddress, string SubnetMask, string State, string ScopeName, string Comment)
        {
            this.ScopeAddress = ScopeAddress;
            this.SubnetMask = SubnetMask;
            this.State = State;
            this.ScopeName = ScopeName;
            this.Comment = Comment;
        }

        public Scope(string ScopeAddress, string SubnetMask, string State, string ScopeName, string Comment, bool initClients)
        {
            this.ScopeAddress = ScopeAddress;
            this.SubnetMask = SubnetMask;
            this.State = State;
            this.ScopeName = ScopeName;
            this.Comment = Comment;

            if (initClients)
                this.Clients = new List<Client>();
        }

        public void InitClients()
        {
            this.Clients = new List<Client>();
        }

        public void InitReservations()
        {
            this.Reservations = new List<Reservation>();
        }

        public string ScopeAddress { get; set; }
        public string SubnetMask { get; set; }
        public string State { get; set; }
        public string ScopeName { get; set; }
        public string Comment { get; set; }

        public List<Client> Clients;
        public List<Reservation> Reservations;
    }

    public class Client
    {
        public Client(string IPAddress, string SubnetMask, string UniqueID, string LeaseExpires, string ClientType)
        {
            this.IPAddress = IPAddress;
            this.SubnetMask = SubnetMask;
            this.UniqueID = UniqueID;
            this.LeaseExpires = LeaseExpires;
            this.ClientType = ClientType;
        }

        public string IPAddress { get; set; }
        public string SubnetMask { get; set; }
        public string UniqueID { get; set; }
        public string LeaseExpires { get; set; }
        public string ClientType { get; set; }
        public Reservation ClientReservation { get; set; }
    }

    public class Reservation
    {
        public Reservation(string IPAddress, string UniqueID, bool ReservationActive)
        {
            this.IPAddress = IPAddress;
            this.UniqueID = UniqueID;
            this.ReservationActive = ReservationActive;
        }

        public string IPAddress { get; set; }
        public string UniqueID { get; set; }
        public string Name { get; set; }
        public string Description { get; set; }
        public string Type { get; set; }
        public bool ReservationActive { get; set; }
    }
}

Then I have a List<DHCP.Client> that I use for DataSource on the gridview. When I set one of the data fields to ClientReservation.ReservationActive I get a not found error.

I have tried this with a List<> where this is no NULL data at all.
So I have to questions:

Can this be done at all?
If I have an object where Client.ClientReservation == null how can I handle that on DataBind() without an error?

Answer 1

I found a solution for both issues. By using a template field like this:

<asp:TemplateField>
  <ItemTemplate>
    <%#DataBinder.Eval(Container.DataItem, "ClientReservation.ReservationActive")%>
  </ItemTemplate>
 </asp:TemplateField>

It get’s the value of the nested class (sub property) and ignores it without error if ClientReservation is NULL.