Dim tbl As New Table()
Dim trg As New TableRowGroup()

tbl.RowGroups.Add(trg)

' Add rows to a TableRowGroup collection.
Dim rowsToAdd As Integer = 4
For x As Integer = 0 To rowsToAdd - 1
    trg.Rows.Add(New TableRow())
Next x

' Insert a new first row (at the zero-index position).
trg.Rows.Insert(0, New TableRow())

' Manipulate rows...

' Set the background on the first row.
trg.Rows(0).Background = Brushes.CornflowerBlue
' Set the font size on the second row.
trg.Rows(1).FontSize = 24
' Set a tooltip for the third row.
trg.Rows(2).ToolTip = "This row's tooltip"

' Adding cells to a row...
    Dim cellsToAdd As Integer = 10
    For x As Integer = 0 To cellsToAdd - 1
        trg.Rows(0).Cells.Add(New TableCell(New Paragraph(New Run("Cell " & (x + 1)))))
    Next x

' Count rows.
Dim rows As Integer = trg.Rows.Count

' Remove 1st row by reference.
trg.Rows.Remove(trg.Rows(0))

' Remove all rows...
trg.Rows.Clear()