However, you can add this functionality yourself by extending the Class Listbox
Insert a Module (or use an existing one) to your project.
Then add this public extension Method to the Module:
Public Sub AddRowAt(Extends l As Listbox, RowNumber As Integer, ParamArray Items() As String)
If (Items.LastIndex < 0) Then
l.AddRowAt(RowNumber, "")
Return
End If
l.AddRowAt(RowNumber, Items(0))
If (Items.LastIndex < 1) Then Return
For i As Integer = 1 To Items.LastIndex
l.CellValueAt(l.LastAddedRowIndex, i) = Items(i)
Next
End Sub
Now you can use your extension like this:
Listbox1.AddRowAt(0, "red", "green", "blue")