vba excel - checkbox click event controlled by listbox selection

[devofish]

I have a checkbox that determines a calculation based on user selection. A record is saved based on each calculation where one column contains the TRUE or FALSE checkbox selection for said record.

How do I incorporate the checkbox value into a listbox click event? That is, when I select a record within the listbox, the checkbox would be checked if TRUE and unchecked if FALSE. What I have does not work, although it doesn't throw an error:

Private Sub lbLag_click()

    Dim ctrl As Control

        With ws
            Me.TextBox1.Text = Me.ListBox1.List(ListBox1.ListIndex, 2)
            '....code continued
            For Each ctrl In Userform1.Controls
                If TypeName(ctrl) = "" Then
                   i = i + 1
                   CheckBox1.value = Sheets(1).Cells(i, 36)
                End If
            Next
        End With  
End Sub