vb.net combo box

[Sascha Lefevre]

Wombaticus wrote:

Still, my "trick" has many applications! (I'm not giving up on it that easily! :) )

:-D I didn't yet have to resort to some such trick - do you have an example where it can't be easily replaced with some non-control-using code?

If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson

[Wombaticus]

Well, it could be used in many places in lieu of a sorting algorithm. If what you’re saying is anything that can be read into a ListBox and sorted that way could be read into a List collection, ok fair enough. I guess this old trick goes back before the days of such things... (If they existed in VB3 I wasn’t aware of them!) I don’t really want to labour the point – it is a “dirty” trick, so probably shouldn’t be encouraged, but it’s quick and as easy to implement as a “proper” solution. Otherwise, OK, I give in! </grovels>

[Sascha Lefevre]

Wombaticus wrote:

I guess this old trick goes back before the days of such things...

Fair enough.. old habits ;)

If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson

[Lost User]

It's a very useful tip when creating a TreeView which lists the items in sorted order. You can also add a prefix character to each item so that directories appear before files.

[Richard Deeming]

You might want to pass StringComparer.OrdinalIgnoreCase to the OrderByDescending function, since file names in Windows aren't case-sensitive. :) If you want to mimic the "natural" sort order that Windows Explorer uses, you'll need a different comparer - for example: Numeric String Sort in C#[^]

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"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

[Sascha Lefevre]

Good suggestion; also the linked article, thank you! :)

If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson

[CHill60]

That's a trick I used many times in VB3, 5 and 6 (and some obscure VB derivatives that I'd rather forget about). I agree with the others that there are (arguably) better "dotnetty" ways of doing it, but it's always worth having something like this up your sleeve (especially if you end up supporting any legacy systems) The only thing I would say is that (when possible) I created the listbox dynamically in code only so it was never part of the forms control collection.

[classy_dog]

Thanks for your helpful answers!

[Sascha Lefevre]

You're welcome!

If the brain were so simple we could understand it, we would be so simple we couldn't. — Lyall Watson

[Jens Madsen Hojby]

Private Function reverseFileNameComparer() As Comparison(Of String)
Return Function(x, y) (String.Compare(Path.GetFileNameWithoutExtension(y), Path.GetFileNameWithoutExtension(x), StringComparison.OrdinalIgnoreCase))
End Function

Private Sub AddToCombo(combo As ComboBox, directoryPath As String, filter As String)
' Error check, 'IsNothing(combo)' and 'IO.Directory.Exists(directoryPath)' bla-bla
combo.BeginUpdate()
For Each fn As String In Directory.EnumerateFiles(directoryPath).OrderByDescending(Function(f) (Path.GetFileNameWithoutExtension(f)))
combo.Items.Add(Path.GetFileNameWithoutExtension(fn))
Next
combo.EndUpdate()

  ' Or...
  Dim files() As String = Directory.GetFiles(directoryPath, filter)
  Array.Sort(files, reverseFileNameComparer)
  combo.Items.AddRange(Array.ConvertAll(files, AddressOf Path.GetFileNameWithoutExtension))

  'Since you want to order by file name, I suggest you use the System.IO namespace:
  'You could:
  combo.FormattingEnabled = True
  'Add a handler to 'ComboBox.Format -
  'or --
  combo.DisplayMember = "Name"
  combo.BeginUpdate()
  For Each fio As FileInfo In New DirectoryInfo(directoryPath).EnumerateFiles(filter).OrderByDescending(Function(f) (f.Name))
      combo.Items.Add(fio.Name)

  Next
  combo.EndUpdate()

End Sub

Private Sub cboFileInfo_format(sender As Object, e As ListControlConvertEventArgs)
Dim f As FileInfo = DirectCast(e.ListItem, FileInfo)
e.Value = f.Name.Substring(f.Name.LastIndexOf("."c) + 1)
End Sub