I guess you may try this

Dim ddl As DropDownList = CType(Me.FormView1.FindControl("DropDownList1"), DropDownList)

If Not ddl Is Nothing

Dim MyString as String = ddl.SelectedItem.Text

End If

or something like above

I see that you have written ListBox but you are using DropDownList, if it is Indeed ListBox, you may replace the DropDownList with ListBox in above code segment

HA!  What was I thinking.
Simply assign a value (without any non-Integer characters) to the DropDownList items.

When taking 2 fields and processing a calculation upon formview insert, what are my options for having this calculated value be binded to a different tablefield (on initial time of insert, all through single insert button click)?