jag sitter och tragglar med en composite control som innehåller 2 textboxar, en knapp, en rangevalidator och en label

Syftet med den är att visa en köp-knapp + ruta för antal i en webshop
om lagerstausen är 0 så skall istället labeln visas

frågan är då hur jag hanterar knapptryckningen i kontrollen så att varan i vald "rad" i min repeater väljs

control.vb

    Public Class BuyPanel : Inherits Control : Implements INamingContainer

        Public Event Click(ByVal Sender As Object, ByVal E As System.EventArgs)


        Private _Quantity As Integer
        Private _RealStock As Integer
        Private _ProdID As Integer

        Public Property ProdID() As Integer
            Get
                'Dim Ctrl As TextBox = Controls(0)
                'Me.EnsureChildControls()
                ' Return Int32.Parse(Ctrl.Text)
                Return _ProdID
            End Get
            Set(ByVal value As Integer)
                ' Dim Ctrl As TextBox = Controls(0)
              '  Me.EnsureChildControls()
                ' Ctrl.Text = value.ToString()
                _ProdID = value
            End Set
        End Property

        Public WriteOnly Property RealStock() As Integer
            Set(ByVal value As Integer)
                _RealStock = value
            End Set
        End Property

        Public Property Quantity() As Integer
            Get
                ' Dim Qty As TextBox = Me.FindControl("txtQty")
                '         Me.EnsureChildControls()
                Return _Quantity
                '
            End Get
            Set(ByVal value As Integer)
                '     Dim Qty As TextBox = Me.FindControl("txtQty")
                '            Me.EnsureChildControls()
                _Quantity = value
            End Set
        End Property

        Public Overrides ReadOnly Property Controls() As ControlCollection
            Get
                EnsureChildControls()
                Return MyBase.Controls
            End Get
        End Property

        Protected Sub OnClick(ByVal e As EventArgs)
            RaiseEvent Click(Me, e)
        End Sub

        Protected Overrides Sub CreateChildControls()

            If _RealStock > 0 Then


                Dim txtProdID As New TextBox
                txtProdID.Text = Me.ProdID
                Me.Controls.Add(txtProdID)

                'Antal-textbox
                Dim txtQty As New TextBox
                txtQty.MaxLength = 3
                txtQty.Columns = 3
                txtQty.ID = "Qty"

                txtQty.Text = Me.Quantity

                Me.Controls.Add(txtQty)

                Dim BuyBtn As New Button
                BuyBtn.Text = "Buy"


                AddHandler BuyBtn.Click, AddressOf BuyBtn_Click

                Me.Controls.Add(BuyBtn)

                '******** Validering ***************
                Dim rv1 As New RangeValidator

                rv1.ControlToValidate = txtQty.ID
                rv1.MinimumValue = 0
                rv1.MaximumValue = _RealStock
                rv1.ErrorMessage = "*"
                rv1.EnableClientScript = True
                Me.Controls.Add(rv1)

            Else
                Dim lbOutOfStock As New Label
                lbOutOfStock.Text = "Out Of Stock"
                Me.Controls.Add(lbOutOfStock)
            End If


        End Sub

        Private Sub BuyBtn_Click(ByVal Sender As Object, ByVal e As EventArgs)

            OnClick(EventArgs.Empty)

        End Sub

    End Class