Kevin, not sure if you found the answer yet or not, BUT
from the attached files it is not clear how do you compile the EXE in the not working app. but I suspect that when you compile as DLL and call it from EXE your form object gets new hidden instance every call and that new instance is what getting filled with the values.
IMHO it would be better to change the "City" function so you are passing the value of "Form1.cbCities.Text" into the function and the function returns back the text you need
something like this
Public Shared Function City(cities As String, state As String) As String Dim result As String = "" Select Case cities Case "Chicago" result = state & "- North Division" Case "New York" result = state & "- Northeast Division" Case "Miami" result = state & "- Southeast Division" Case "Dallas" result = state & "- MidSouth Division" End Select Return result End Function
Call it from the form as
form1.txtCombined.Text = cities.City(cbCities.Text,txtState.Text)
this should work ...