You can use the built-in Dir function or the FileSystemObject.
They each have their own strengths and weaknesses.
Dir Function
The Dir Function is a built-in, lightweight method to get a list of files. The benefits for using it are:
- Easy to Use
- Good performance (it's fast)
- Wildcard support
The trick is to understand the difference between calling it with or without a parameter. Here is a very simple example to demonstrate:
Public Sub ListFilesDir(ByVal sPath As String, Optional ByVal sFilter As String)
Dim sFile As String
If Right(sPath, 1) <> "\" Then
sPath = sPath & "\"
End If
If sFilter = "" Then
sFilter = "*.*"
End If
'call with path "initializes" the dir function and returns the first file name
sFile = Dir(sPath & sFilter)
'call it again until there are no more files
Do Until sFile = ""
Debug.Print sFile
'subsequent calls without param return next file name
sFile = Dir
Loop
End Sub
If you alter any of the files inside the loop, you will get unpredictable results. It is better to read all the names into an array of strings before doing any operations on the files. Here is an example which builds on the previous one. This is a Function that returns a String Array:
Public Function GetFilesDir(ByVal sPath As String, _
Optional ByVal sFilter As String) As String()
'dynamic array for names
Dim aFileNames() As String
ReDim aFileNames(0)
Dim sFile As String
Dim nCounter As Long
If Right(sPath, 1) <> "\" Then
sPath = sPath & "\"
End If
If sFilter = "" Then
sFilter = "*.*"
End If
'call with path "initializes" the dir function and returns the first file
sFile = Dir(sPath & sFilter)
'call it until there is no filename returned
Do While sFile <> ""
'store the file name in the array
aFileNames(nCounter) = sFile
'subsequent calls without param return next file
sFile = Dir
'make sure your array is large enough for another
nCounter = nCounter + 1
If nCounter > UBound(aFileNames) Then
'preserve the values and grow by reasonable amount for performance
ReDim Preserve aFileNames(UBound(aFileNames) + 255)
End If
Loop
'truncate the array to correct size
If nCounter < UBound(aFileNames) Then
ReDim Preserve aFileNames(0 To nCounter - 1)
End If
'return the array of file names
GetFilesDir = aFileNames()
End Function
File System Object
The File System Object is a library for IO operations which supports an object-model for manipulating files. Pros for this approach:
- Intellisense
- Robust object-model
You can add a reference to to "Windows Script Host Object Model" (or "Windows Scripting Runtime") and declare your objects like so:
Public Sub ListFilesFSO(ByVal sPath As String)
Dim oFSO As FileSystemObject
Dim oFolder As Folder
Dim oFile As File
Set oFSO = New FileSystemObject
Set oFolder = oFSO.GetFolder(sPath)
For Each oFile In oFolder.Files
Debug.Print oFile.Name
Next 'oFile
Set oFile = Nothing
Set oFolder = Nothing
Set oFSO = Nothing
End Sub
If you don't want intellisense you can do like so without setting a reference:
Public Sub ListFilesFSO(ByVal sPath As String)
Dim oFSO As Object
Dim oFolder As Object
Dim oFile As Object
Set oFSO = CreateObject("Scripting.FileSystemObject")
Set oFolder = oFSO.GetFolder(sPath)
For Each oFile In oFolder.Files
Debug.Print oFile.Name
Next 'oFile
Set oFile = Nothing
Set oFolder = Nothing
Set oFSO = Nothing
End Sub
