Timing problem? Variable does not always update
 

All my (programming) life I’ve been plagued by timing problems! I assumed (haha) that when I changed from a pervasively multitasking OS to Vista I would escape the problem but it seems like I must be missing something.
My problem lies in WhichChar. Note the line:
'MsgBox(vbNullString)
If I leave it commented out, the StringBuilder retVal is only occasionally updated, about half the time. If I uncomment the MsgBox line, retVal is always correctly updated.
I did see that the Controls are not guaranteed to be thread-safe, that may be the problem I am running into. I have two more problems with ComboBoxes in general, but I will keep digging to see if I can resolve them myself.

    Private Sub asteriskComboBox_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles asteriskComboBox.SelectedIndexChanged

       WhichChar(asteriskComboBox, asteriskReplacement, asteriskComboIndex)

    End Sub



    Public Sub WhichChar(ByVal CBox As ComboBox, ByRef retVal As StringBuilder, ByRef indexToChange As Integer)

        If Not isInstantiating Then

            indexToChange = CBox.SelectedIndex

            Dim selectedIndex As Integer

            selectedIndex = CBox.SelectedIndex

            Dim selectedItem As New Object

            selectedItem = CBox.SelectedItem

            retVal.Length = 0

            'MsgBox(vbNullString)

            Select Case indexToChange

                Case 0  'single space

                    retVal.Append(" ")

                Case 1  'hyphen

                    retVal.Append("-")

                Case 2  'single space>hyphen<single space>

                    retVal.Append(" - ")

                Case 3  'open single quote

                    retVal.Append("`")

                Case 4  '' close single quote

                    retVal.Append("'")

                Case 5  'underscore

                    retVal.Append("_")

                Case Else   'everything else

                    retVal.Append(CBox.SelectedText)

            End Select

        End If

    End Sub

This is a project with multiple purposes. The actual job of the program is to rename songs. I am using iTunes to put my CD collection on my computer. Most of the CDs are identified automatically, others I can ID with a few of the free online DB services. A handful I can find the track list online but not in a database. In these cases the file name and song title look like “01 Track 01”, “Track 1” or “01 Track”.
Entering all this info manually would take less time than writing the code! So, I last worked in Basic in the late ‘70s, got into C then C++ as soon as alpha wear was available. I recently switched to Windows and thought I would play with a bit of programming. This is my first attempt (after “Hello, world!”) and I am finding the going a bit slow.

Thanks in advance for the help I get!

-Ed

Re: Timing problem? Variable does not always update
 

just for kicks and laughs, let's try to replace the (or just below the line of) 'msgbox line with Application.Doevents(). I've noticed that sometimes when a msgbox makes code work that doesn't seem to work without it, a Doevents is the right medicine. Let me know if it works or not.

Re: Timing problem? Variable does not always update
 

No, did not help. In fact made the problem 100%--with neither MsgBox nor Doevents it picks up three or four of the eight Listboxes. With Doevents it gets none!

-Ed

Re: Timing problem? Variable does not always update
 

I have (I think) determined the problem. My terminology is very rusty, but I think the word is “scope” (might now be a Namespace thing).

Here is what is going on…

The Form and the ComboBox were created in the VB visual editor. As I expected this to be a simple project (HaHa) I decided to put all the code within the

Public Class form1…End Class

code section (as the beginner examples like “Hello, world!” seem to do. VB declares all the gadgets and underlying support code (

main()

etc.) in some hidden file—I found it once but seem to have lost it! The ComboBox is declared as somewhat global, but it’s member Subs are somehow private (is my guess).

This mean that when I call

Private Sub ComboBox_SelectedIndexChanged()

and within that function examine the contents of

ComboBox.SelectedText

the value returned is accurate, but when I pass (ByRef or ByVal) ComboBox to

Public Sub WhichChar()

the values returned by

ComboBox.SelectedText

are in fact wild pointers and only accidently point to anything reasonable occasionally.

I need to learn how to create classes which inherit from others (I do that in C++--maybe I should simply try Visual C++) That way I might be able to get the data out of the ComboBox any time I needed it. Have to play around with it some.