How to handle null reference in asp.net Repeater item with foreign-key relations

Question

I'm having trouble with null reference in asp.net repeater control. The repeater iterates through an IEnumerable<T> of a class with referenced properties. I have the following classes:

public class SubTarget
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int? ModelId { get; set; }

    public virtual Model Model { get; set; }
}

public class Model
{
    public int Id { get; set; }
    public string Name { get; set; }

    public Model()
    {
        SubTargetTypes = new HashSet<SubTargetType>();
    }
}

And repeater control:

<asp:Repeater
    runat="server" ItemType="SubTarget" SelectMethod="GetSubTargets">
    <ItemTemplate>
        <div>
            <table>
                <tr>
                    <td><%# Item.SubTargetType.Name %></td>
                    <td><%# Item.Model.Name %></td>
                </tr>
            </table>
        </div>
    </ItemTemplate>
</asp:Repeater>

The problem is: Model property on SubTarget is optional. So when ModelId is null, the references to properties on Model obviously can't be found. The repeater control correctly handles the null ModelId when called with just <%# Item.Model %> and leaves the space empty, but when calling <%# Item.Model.Name %> I get a null reference exception.

Any ideas how to display just blank space when Foreign key is not set?

Answer 1

Try this :

 <td><%# Item.Model !=null ? Item.Model.Name : string.Empty %></td>

I hope help you. :)