How to bind generic list with the ComboBoxAdv?

List<Country> CountryList = new List<Country>();
//Adds the item into the list
CountryList.Add(new Country { Key = "India" });
CountryList.Add(new Country { Key = "US" });
CountryList.Add(new Country { Key = "UK" });
CountryList.Add(new Country { Key = "China" });
//Binds the list to the ComboBoxAdv
comboBoxAdv1.DataSource = CountryList;
comboBoxAdv1.DisplayMember = "Key";
private void comboBoxAdv1_SelectedIndexChanged(object sender, EventArgs e)
{
    this.listBox1.Items.Clear();
    //Gets the ComboBoxAdv SelectedItem
    Country selectedCountry = comboBoxAdv1.SelectedItem as Country;
    this.listBox1.Items.Add(selectedCountry.Key); 
}
//Specifies the List
public class Country
{
    public string Key {get; set;}
}

Dim CountryList As New List(Of Country)()
'Adds the item into the list
CountryList.Add(New Country With {.Key = "India"})
CountryList.Add(New Country With {.Key = "US"})
CountryList.Add(New Country With {.Key = "UK"})
CountryList.Add(New Country With {.Key = "China"})
'Binds the list to the ComboBoxAdv
comboBoxAdv1.DataSource = CountryList
comboBoxAdv1.DisplayMember = "Key"
Private Sub comboBoxAdv1_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles comboBoxAdv1.SelectedIndexChanged
 Me.listBox1.Items.Clear()
 'Gets the ComboBoxAdv SelectedItem
 Dim selectedCountry As Country = TryCast(comboBoxAdv1.SelectedItem, Country)
 Me.listBox1.Items.Add(selectedCountry.Key)
End Sub
'Specifies the List
Public Class Country
   Private privateKey As String
   Public Property Key() As String
    Get
     Return privateKey
    End Get
    Set(ByVal value As String)
     privateKey = value
    End Set
   End Property
End Class