How to insert an empty row in a combobox filled by linq?

I have a list of Items, given by Linq from the DB. Now I filled a ComboBox with this list.

How I can get an empty row in it?

My problem is that in the list the values aren't allowed to be null, so I can't easily add a new empty item.

From stackoverflow

• Can't you add an empty Item to the ComboBox after the bind?

  Kovu : This was my idea, but I cant at beginning of the combobox, only at end, can I?

• Can you try doing this:

  Dropdown.Items.Insert(0, String.Empty)
  

  The other bit of success I've had is to create an empty item and insert it at the beginning of my datasource before I bind to the dropdown.

• You can use Concat() to append your real data after the static item. You'll need to make a sequence of the empty item, which you can do with Enumerable.Repeat():

  list.DataSource = Enumerable.Repeat(new Entity(), 1)
                   .Concat(GetEntitiesFromDB());
  

  Or by defining a simple extension method (in set theory a singleton is a set with cardinality 1):

  public IEnumerable<T> AsSingleton<T>(this T @this)
  {
      yield return @this;
  }
  
  // ...
  list.DataSource = new Entity().AsSingleton().Concat(GetEntitiesFromDB());
  

  Or even better, write a Prepend method:

  public IEnumerable<T> Prepend<T>(this IEnumerable<T> source, params T[] args)
  {
      return args.Concat(source);
  }
  
  
  // ...
  list.DataSource = GetEntitiesFromDB().Prepend(new Entity());
  

• Nope- throws ArgumentException

  "Items collection cannot be modified when the DataSource property is set."