How do I add the row number to each item selected in an insert into select statement

Dim lastRow = dtc.Rows.Cast(Of DataRow)().LastOrDefault()
       Dim I As Integer = 0
       I += 1

       Dim laststr As String = lastRow.Item("ID").ToString + I

       'This is for personal information input

       Using sqlconn As New SqlConnection("SQLstring")

           Using da As New SqlDataAdapter(String.Empty, sqlconn)

               Dim sql As New StringBuilder("insert into [")
               sql.Append(TreeView1.SelectedNode.Text.Replace("]", "\]"))
               sql.Append("] (")

               Dim sql1 As New StringBuilder("")

               Dim andRequired As Boolean = False

               If datat.Columns.Contains("ID") Then

                   If andRequired Then
                       sql.Append(", ")
                       sql1.Append(", ")
                   End If

                   sql.Append("[Individual_ID]")
                   sql1.Append(laststr)
                   andRequired = True

               End If

               sql.AppendFormat(") Select " + sql1.ToString + " from table2")
               da.SelectCommand.CommandText = sql.ToString()

               MessageBox.Show(sql.ToString)

               da.Fill(datat)

           End Using

       End Using

Dim I As Integer = 0
      I += 1

      Dim laststr As String = lastRow.Item("ID").ToString + I