Protected Sub ListView1_PreRender(ByVal sender As Object, ByVal e As System.EventArgs) Handles ListView1.PreRender
        For Each item As ListViewItem In ListView1.Items
            Dim b As Button = CType(item.FindControl("EditButton"), Button)
            If (Not b Is Nothing) Then
                If ...
                    b.Visible = True
                Else
                    b.Visible = False
                End If
            End If
        Next
    End Sub