With Me.MyListBox    'the name of your listbox  
    .RowSource = PopListBox("c:\",'txt")   ' You can leave the ext. out to show all files  
    .RowSourceType = "value list"
End With

'Form1=Name of your form the listbox is on
'MyListBox = Name of your list box.
'C:\ =  The name of your directory. Note this must be the same as in the PopListBox Function.
    
On Error Resume Next
Application.FollowHyperlink OpenListItem("Form1", "MyListBox", "c:\")

  
Function PopListBox(strPath As String, Optional FileExtension As String) As String

Dim MyFso As Object
Dim MainDir As Object
Dim MyFile As Object
Dim LstItems As String, FileProp As String
Dim NameLength As Integer, InitialNameLength As Integer, TypeLength As Integer, InitialTypeLength As Integer
Dim x As Integer, y As Integer
Dim NameSep As Integer, TypeSep As Integer
Dim Placer As Variant

On Error Resume Next

Set MyFso = CreateObject("scripting.FileSystemObject")
Set MainDir = MyFso.GetFolder(strPath)

InitialNameLength = 1
InitialTypeLength = 1

For Each MyFile In MainDir.Files ' all this in side this loop is to help try and format the columns a bit more uniformly.
        NameLength = Len(MyFile.Name)
        x = IIf(NameLength > InitialNameLength, NameLength, InitialNameLength)
        InitialNameLength = x
        
        TypeLength = Len(MyFile.Type)
        y = IIf(TypeLength > InitialTypeLength, TypeLength, InitialTypeLength)
        InitialTypeLength = y
Next

For Each MyFile In MainDir.Files
    Placer = InStr(1, MyFile.Name, ".") - 1
    NameSep = x - Len(MyFile.Name) + 4
    TypeSep = y - Len(MyFile.Type) + 4
    
    If Mid(MyFile.Name, InStr(1, MyFile.Name, ".") + 1) = FileExtension Then
        FileProp = Mid(MyFile.Name, 1, Placer) & String(NameSep, "_") & MyFile.Type & String(TypeSep, "_") & MyFile.DateCreated
        LstItems = LstItems & FileProp & ";"
    ElseIf FileExtension = "" Then
        FileProp = Mid(MyFile.Name, 1, Placer) & String(NameSep, "_") & MyFile.Type & String(TypeSep, "_") & MyFile.DateCreated
        LstItems = LstItems & FileProp & ";"
    End If
    
Next

Debug.Print LstItems
'Clean up
Set MyFso = Nothing
Set MainDir = Nothing

PopListBox = UCase(LstItems)

End Function

Function OpenListItem(FormName As String, ControlName As String, strPath As String) As String

Dim frm As Form
Dim ctl As Control
Dim intI As Integer
Dim MyVar As Variant
Dim strFileName As String
Dim MyFso As Object
Dim MainDir As Object
Dim MyFile As Object

On Error Resume Next
Set MyFso = CreateObject("scripting.FileSystemObject")
Set MainDir = MyFso.GetFolder(strPath)
Set frm = Forms(FormName)
Set ctl = frm.Controls(ControlName)

For Each MyVar In ctl.ItemsSelected
    strFileName = ctl.ItemData(MyVar)
    strFileName = Mid(strFileName, 1, InStr(1, strFileName, "_") - 1)
    
    For Each MyFile In MainDir.Files
        If Mid(MyFile.Name, 1, InStr(1, MyFile.Name, ".") - 1) = strFileName Then
            OpenListItem = MyFile.Path
            Exit For
        End If
    Next
Next

End Function