I'm writing a CompositeControl that includes a child GridView.  I want
to expose the GridView's Columns property at design time and allow the
developer to customize the columns, but don't want them to set the
DataSourceID, etc.  So, I did this on my control:

<PersistenceMode(PersistenceMode.InnerProperty), _

Editor(GetType(System.Web.UI.Design.WebControls.DataControlFieldTypeEditor),
GetType(UITypeEditor)), _
        MergableProperty(False), _
        DefaultValue(CStr(Nothing)), _

DesignerSerializationVisibility(DesignerSerializationVisibility.Content)>
_
        Public ReadOnly Property Columns() As
DataControlFieldCollection
            Get
                Me.EnsureChildControls()
                Return memberGridView.Columns
            End Get
        End Property

However, the DataControlFieldTypeEditor does not appear when the [...]
button is clicked  in the property grid.  No UI or error occurs at all.
Using Reflector, I suspect that this is because the control is not a
DataBoundControl:

Public Overrides Function EditValue(ByVal context As
ITypeDescriptorContext, ByVal provider As IServiceProvider, ByVal value
As Object) As Object
      Dim control1 As DataBoundControl =
TryCast(context.Instance,DataBoundControl)
      If (control1 Is Nothing) Then
            Return Nothing
      End If
....

But I'm stuck there.  So, my question is: How can I expose a Columns
property and get the design-time behavior identical to the GridView?

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