VB .NET error handling, pass error to caller - vb.net

Question

this is my very first project on vb.net and i am now struggling to migrate a vba working add in to a vb.net COM Add-in. I think i'm sort of getting the hang, but error handling has me stymied.
This is a test i've been using to understand the try-catch and how to pass exception to caller
Public Sub test()
Dim ActWkSh As Excel.Worksheet
Dim ActRng As Excel.Range
Dim ActCll As Excel.Range
Dim sVar01 As String
Dim iVar01 As Integer
Dim sVar02 As String
Dim iVar02 As Integer
Dim objVar01 As Object
ActWkSh = Me.Application.ActiveSheet
ActRng = Me.Application.Selection
ActCll = Me.Application.ActiveCell
iVar01 = iVar02 = 1
sVar01 = CStr(ActCll.Value)
sVar02 = CStr(ActCll.Offset(1, 0).Value)
Try
objVar01 = GetValuesV(sVar01, sVar02)
'DO SOMETHING HERE
Catch ex As Exception
MsgBox("ERROR: " + ex.Message)
'LOG ERROR SOMEWHERE
Finally
MsgBox("DONE!")
End Try
End Sub
Private Function GetValuesV(ByVal QryStr As Object, ByVal qryConn As String) As Object
Dim cnn As Object
Dim rs As Object
Try
cnn = CreateObject("ADODB.Connection")
cnn.Open(qryConn)
rs = CreateObject("ADODB.recordset")
rs = cnn.Execute(QryStr)
If rs.EOF = False Then
GetValuesV = rs.GetRows
Else
Throw New System.Exception("Query Return Empty Set")
End If
Catch ex As Exception
Throw ex
Finally
rs.Close()
cnn.Close()
End Try
End Function
i'd like to have the error message up to test, but
MsgBox("ERRORE: " + ex.Message)
pops out something unexpected (Object variable or With block variable not set)
What am i doing wrong here??
Thanks
D

Answer 1

It may be because you're doing a
Throw ex
Try using
Throw
instead. This maintains the error stack, instead of generating a new one each time.
Based on your comments, I think the specific problem you're getting is in your Finally block. You're trying to close the recordset and the connection, but if you got an error when you instantiated them, they will not exist; therefore, you get the Object variable or with block error.
(I would put the connection is a using statement anyway).