Forms :: Use Numericupdown To Multiply String In Richtextbox?

2 forms, on the first form I have a listbox which recieves it's items from a datagridview, when I click on a button all the items (in the listbox) are converted to a string and add to a richtextbox on the second form.

On the second form I have also a numericupdown, and here is what I run into.

With the numericupdown I want to multiply or remove blocks of strings from the richtextbox.

For example, when clicked on the button (form1) a string is add to the richtextbox, when I click (on form2) on the upbutton of the numericupdown I want to add the same string again below the existing one with 2 blank lines between them (this can be down a lot of times). When I click the downbutton, a string should be removed.

In short term, the amount in the numericupdown should be the amount of string blocks in the richtextbox.

Here is the code I use to copy listbox.items to string and add them to the richtextbox:

Public Sub SGLists()
Dim i As String
For Each i In Me.ListBox1.Items

[Code]....