Excel VBA with Microstation Folder Search - vba

Question

i currently have this code in one of the macros for work. It is located under a button for browsing which folder to look into, and it will get the .DGNs and add them to a listbox.
I don't quite understand the code fully was hoping someone can give me a quick run down. Also, the code only looks at the selected folder for .DGNs, i want it to look into sub folders as well, is that possible?
Dim myFSO As New Scripting.FileSystemObject
Dim myFolder As Scripting.Folder
Dim myFile As Scripting.File
Dim myShell As New Shell32.Shell
Dim myRootFolder As Shell32.Folder3
Set myRootFolder = myShell.BrowseForFolder(0, "Pick", 0)
If myRootFolder Is Nothing Then Exit Sub
Set myFolder = myFSO.GetFolder(myRootFolder.Self.path)
txtCurrentFolder.Text = myRootFolder.Self.path
lstFilesInFolder.Clear
For Each myFile In myFolder.Files
Select Case UCase(Right(myFile.Name, 3))
Case "DGN"
If IsFileIn(myFile.path, lstFilesToProcess) = False Then
lstFilesInFolder.AddItem myFile.path
End If
End Select
Next

Answer 1

The code shows a GUI to select a folder, then iterates through the folder's child files testing if their names end in DGN and if so then testing if the file is already in some collection (lstFilesInFolder) and if not then adding it.
I think the approach seems a little complicated (picking a folder(s) can be done simply without using the Shell through Application.FileDialog) and I cannot judge some parts (like is it necessary to test lstFilesInFolder etc) without the rest of the code, and just personally I dislike the use of myX as a variable naming convention. Nevertheless, it does what it seems it is meant to do.
I like a stack/queue based approach to 'recursion' rather than actual recursive calls.
An example of converting your code to something that looks in subfolders as well is: (see comments on my added lines)
Dim myFSO As Scripting.FileSystemObject 'changed from late-binding
Set myFSO = New Scripting.FileSystemObject
Dim folderQueue As Collection 'queue
Set folderQueue = New Collection 'instantiate
Dim myFolder As Scripting.Folder
Dim subfolder As Scripting.Folder 'var for enumerating subfolders
Dim myFile As Scripting.File
Dim myShell As New Shell32.Shell
Dim myRootFolder As Shell32.Folder3
Set myRootFolder = myShell.BrowseForFolder(0, "Pick", 0)
If myRootFolder Is Nothing Then Exit Sub
folderQueue.Add myFSO.GetFolder(myRootFolder.Self.path) 'enqueue
Do While folderQueue.Count > 0 ''recursive' loop
Set myFolder = folderQueue(1) 'get next folder
folderQueue.Remove 1 'dequeue
txtCurrentFolder.Text = myRootFolder.Self.path
lstFilesInFolder.Clear
For Each subfolder in myFolder.SubFolders 'loop through subfolders adding for processing
folderQueue.Add subfolder 'enqueue
Next
For Each myFile In myFolder.Files
Select Case UCase(Right(myFile.Name, 3))
Case "DGN"
If IsFileIn(myFile.path, lstFilesToProcess) = False Then
lstFilesInFolder.AddItem myFile.path
End If
End Select
Next
Loop
As a final point, it is sometimes considered good practice to switch the use of a reference to a specific version of the Scripting library (nice for static typing) to using e.g. CreateObject("Scripting.FileSystemObject") before releasing to other users as the use of a reference can sometimes cause issues.