DataSource property on a User control grayed out

I have a user control with a datagridview to show an address list in a popup, that the user can choose from.
I followed a Microsoft MSDN example. However, when I drag the built usercontrol onto a form, the DataSource property in the property grid of the control remains grayed out. Thus I can't set a datasource property during desgin time.

What am I doing wrong?
This is my code:

Imports PrismaModel
Imports System.ComponentModel

<System.ComponentModel.ComplexBindingProperties("DataSource", "DataMember")> _
Public Class AdressenControl

  Public Event AdresDoubleClicked(ByVal adres As Adres)

  Public Property DataSource() As Object
    Get
      Return Me.ZaDatagridView1.Datasource
    End Get
    Set(ByVal value As Object)
      Me.ZaDatagridView1.Datasource = Me.ZaDatagridView1.Datasource
    End Set
  End Property

  Public Property DataMember() As String
    Get
      Return Me.ZaDatagridView1.DataMember
    End Get
    Set(ByVal value As String)
      Me.ZaDatagridView1.DataMember = value
    End Set
  End Property

  Private Sub ZaDatagridView1_CellDoubleClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles ZaDatagridView1.CellDoubleClick

    If e.RowIndex > -1 Then
      Dim adres As Adres
      Dim list As List(Of Adres) = ZaDatagridView1.Datasource
      adres = list(e.RowIndex)
      RaiseEvent AdresDoubleClicked(adres)
    End If
  End Sub

End Class

Tags: Visual Basic (Visual Basic 10), Entity Framework, DataGridView