Imports System
Imports System.IO
Imports System.Runtime
Imports System.Runtime.InteropServices
 
Public Class frmEnumerateFiles
 
    'Code übernommen und leicht modifiziert von .... 
    'https://www.vbarchiv.net/forum/read.php?f=10&t=59926&i=59957
 
    Private Declare Auto Function FindFirstFile Lib "kernel32.dll" (ByVal _
          lpFileName As String, ByRef lpFindData As WIN32_FIND_DATA) As IntPtr
 
    Private Declare Auto Function FindNextFile Lib "kernel32.dll" (ByVal _
        hFindFile As IntPtr, ByRef lpFindData As WIN32_FIND_DATA) As IntPtr
 
    Private Declare Function FindClose Lib "kernel32.dll" (ByVal hFindFile As _
        IntPtr) As Boolean
 
 
    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)>
    Private Structure WIN32_FIND_DATA
        Public sfileAttributes As Int32
        Public creationTime_lowDateTime As Int32
        Public creationTime_highDateTime As Int32
        Public lastAccessTime_lowDateTime As Int32
        Public lastAccessTime_highDateTime As Int32
        Public lastWriteTime_lowDateTime As Int32
        Public lastWriteTime_highDateTime As Int32
        Public nFileSizeHigh As Int32
        Public nFileSizeLow As Int32
        Public dwReserved0 As Int32
        Public dwReserved1 As Int32
        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=MAX_PATH)>
        Public fileName As String
        <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=14)>
        Public alternateFileName As String
    End Structure
 
 
    Private Const MAX_PATH As Integer = 260
    Private Const INVALID_HANDLE_VALUE As Integer = -1
    Private Const FILE_ATTRIBUTE_DIRECTORY As Integer = &H10
 
 
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
          System.EventArgs) Handles MyBase.Load
 
        Dim files As New List(Of String)
        FindAllFiles("C:\users", "*.pdf", files)
        Stop
    End Sub
 
 
 
    Private Sub FindAllFiles (ByVal folder As String, ByVal pattern As String, 
                              ByRef files As List(Of String))
 
        Dim w32data As New WIN32_FIND_DATA
        Dim Handle As System.IntPtr = FindFirstFile(Path.Combine(folder, _
          "*.*"), w32data)
        If Handle <> CType(INVALID_HANDLE_VALUE, System.IntPtr) Then
            Dim Search As Boolean = True
            Do
                'Handelt es sich um ein Verzeichnis? 
                If (w32data.sfileAttributes And FILE_ATTRIBUTE_DIRECTORY) =
                      FILE_ATTRIBUTE_DIRECTORY Then
                    'Verzeichnisnamen ermitteln und für den späteren rekursiven 
                    ' Aufruf speichern 
                    If w32data.fileName <> "." And w32data.fileName <> ".." Then
                        FindAllFiles(Path.Combine(folder, w32data.fileName),
                              pattern, files)
                    End If
                Else
                    'es ist eine datei
                    If w32data.fileName Like pattern Then
                        files.Add(Path.Combine(folder, w32data.fileName))
                    End If
                End If
            Loop Until FindNextFile(Handle, w32data) = CType(False, _
              System.IntPtr)
 
            'handle schliessen
            FindClose(Handle)
        End If
    End Sub
End Class