ASP.Net สอบถามเรื่องการรับค่าจาก TextBox ใน GridView หน่อยครับ

    Sub Button1_Click(sender As Object, e As EventArgs)
        Dim chkCusID As CheckBox
        Dim lblID As Label
        Dim i As Integer
        lblText.Text = ""
        For i = 0 To myGridView.Rows.Count - 1
            chkCusID = myGridView.Rows(i).FindControl("chkCustomerID")
            lblID = myGridView.Rows(i).FindControl("lblCustomerID")
            IF chkCusID.Checked = True Then
                '*** Have lblID.Text ***'
                Me.lblText.Text = Me.lblText.Text & "<br>" & lblID.Text
            End IF
        Next
    End Sub

            IF Not Page.IsPostBack() Then
                BindData()
            End IF

                Dim box0 As TextBox = New TextBox()
                box0.ID = "itemcode_detail"
                box0.Attributes.Add("runat", "server")
                box0.Text = e.Row.Cells(0).Text
                e.Row.Cells(0).Controls.Add(box0)
                e.Row.Cells(0).Width = 100

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Page.IsPostBack Then
            Dim tblID As TextBox
            For i = 0 To GridViewDetail.Rows.Count - 1
                tblID = GridViewDetail.Rows(i).FindControl("itemcode_detail")
                If Not IsNothing(tblID) Then
                    Response.Write(tblID.Text)
                End If
            Next
        End If
   End Sub