DataSource containing null causes ComboBox to crash

I have selected myself headfirst in C # and .Net 2.0 using Linq and I have several problems debugging some of the problems, namely the following:

I have a ComboBox ( cmbObjects

) control . I want to populate a collection of objects obtained using Linq. I wrote a helper method to fill the List<T>

generic:

class ObjectProvider
{

    public static List<T> Get<T>(bool includeNull) where T : class, new()
    {
        List<T> list = new List<T>();
        LutkeDataClassesDataContext db = ConnectionManager.GetConnection();
        IQueryable<T> objects = db.GetTable<T>().AsQueryable();

        if (includeNull) list.Add(null);

        foreach (T o in objects) list.Add(o);

        return list;
    }

    public static List<T> Get<T>() where T : class, new()
    {
        return Get<T>(false);
    }
}

      

        
        
        
      

    

I checked the results when calling a function with true or false value - List

contains correct values, when passed true

it contains null

as first value followed by other objects.

When assigned DataSource

to ComboBox

, however, the control simply refuses to display any items, including the value null

(not selectable):

cmbObjects.DataSource = ObjectProvider.Get<Car>(true);

      

        
        
        
      

    

Passing in false

(or no parameter) works - displays all objects.

Is there a way to specify a "zero" value for the first object without resorting to magic number objects (eg having a false entry in the DB just to indicate the N / A value)? Something along the zero-valued lines would be perfect, but I'm lost.

Also, I tried adding new T()

instead null

to the list, but that only resulted in OutOfMemoryException

.