Renumbering a Work Breakdown Structure (WBS) in a datatable - vb.net

Question

A multi-level WBS the users were able to delete some tasks that are not applicable to their project. Goal is to renumber the entire WBS so that no numbers are skipped. Example: 1.1.1, 1.1.2, 1.1.4 - number 1.1.3 was deleted. Each WBS element may or may not have child elements that need to be renumbered as well.
I have the data in a datatable, fields: WBS_ID, WBSNo, ParentID, ParentNo, SortKey(the original WBS Number) and Notes. WBS_ID is the UID, ParentID is the WBS_ID of the parent WBS element. First element of the WBS has a null value in the ParentID field.
I cannot seem to grasp how to make an iterative function call to create the WBS number.
Dim dTb As New DataTable
Using Conn
Conn.Open()
Using dad As New SqlClient.SqlDataAdapter(vSqlStr, Conn)
dad.SelectCommand.Parameters.Add("#ProjectID", SqlDbType.Int)
dad.SelectCommand.Parameters.Add("#Revision", SqlDbType.Int)
dad.SelectCommand.Parameters("#ProjectID").Value = vProjectID
dad.SelectCommand.Parameters("#Revision").Value = vRevision
dad.Fill(dTb) 'Now we have a table with all the elements .
End Using
Conn.Close()
End Using
'Now work with the datatable
'WBS_ID, WBSNo, WBSLevel, ParentID, ParentNo, SortKey, Notes
dTb.DefaultView.Sort = "SortKey ASC"
dTb = dTb.DefaultView.ToTable
Dim vRowCount As Int16
vRowCount = dTb.Rows.Count
Dim vCurRow As Int16 = 0
For x = 0 To vRowCount - 1
If Not IsDBNull(dTb.Rows(x)("ParentID")) Then
Else
dTb.Rows(x)("WBSNo") = "1"
End If
dTb.Rows(x)("Notes") = dTb.Rows(x)("Notes") & vbCrLf & "<<< Old WBS No. = " & dTb.Rows(x)("SortKey")
Next
Renumber the WBS, starting with "1", each child of an element would be numbered with the parent number, plus a period (.) then sequentially starting with 1; each child could have children.

Answer 1

I wrote a recursive sub-routine to update the datatable, then another routine to update the database.
Sub RenumberChildren(vParentID As Int16, vParentWBSNo As String)
Dim ChildCount As Int16 = 0
For x = 0 To dTb.Rows.Count - 1
If Not IsDBNull(dTb.Rows(x)("ParentID")) Then
If dTb.Rows(x)("ParentID") = vParentID Then
ChildCount += 1
dTb.Rows(x)("WBSNo") = vParentWBSNo & "." & ChildCount
RenumberChildren(dTb.Rows(x)("WBS_ID"), dTb.Rows(x)("WBSNo"))
End If
End If
Next
End Sub