Imports System.IO
 
Public Class Form1
    Private Quelle, Ziel As String
    Dim files As New List(Of CopyInfo)
 
    Public Structure CopyInfo
        Public source As String
        Public destination As String
    End Structure
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        Button1.Enabled = False
 
        Quelle = "C:\Users\fabian\Documents\Schule"
        Ziel = "C:\Users\fabian\Documents\Schule_Backup"
        Dim df As New IO.DirectoryInfo(Quelle)
        GetNewFilesEx(df, files)
 
        Dim th As New Threading.Thread(AddressOf CopyFiles)
        th.Start()
    End Sub
 
    Private Delegate Sub SetPB(ByVal val As Integer)
    Private Sub SetProgress(ByVal val As Integer)
        pb.Value = val
    End Sub
 
    Private Sub CopyFiles()
        For i As Integer = 0 To files.Count - 1
            File.Copy(files(i).source, files(i).destination, True)
            Me.Invoke(CType(AddressOf SetProgress, SetPB), CInt(((i + 1) / _
              files.Count) * 100))
            Console.WriteLine(i & " / " & files.Count)
        Next
    End Sub
 
    Sub GetNewFilesEx(ByVal subdir As IO.DirectoryInfo, ByRef files As List(Of _
      CopyInfo))
        For Each f As IO.FileInfo In subdir.GetFiles
            'nachfragen ob Datei schon besteht
            If IO.File.Exists(f.FullName.Replace(Quelle, Ziel)) = False Then
                'Schauen ob Ordner schon esteht
                If IO.Directory.Exists(f.DirectoryName.Replace(Quelle, Ziel)) = _
                  False Then
                    'wenn nein dann erstellen
                    IO.Directory.CreateDirectory(f.DirectoryName.Replace( _
                      Quelle, Ziel))
                End If
                'Wenn nein dann kopieren
                Dim ci As CopyInfo
                ci.source = f.FullName
                ci.destination = f.FullName.Replace(Quelle, Ziel)
                files.Add(ci)
            Else
                'wenn Datei schon besteht, dann prüfen ob neuer
                Dim sf As New IO.FileInfo(f.FullName.Replace(Quelle, Ziel))
                If f.LastWriteTime > sf.LastWriteTime Then
                    Dim ci As CopyInfo
                    ci.source = f.FullName
                    ci.destination = f.FullName.Replace(Quelle, Ziel)
                    files.Add(ci)
                End If
            End If
        Next
 
        'und das selbe für alle Unterverzeichnisse
        For Each di As IO.DirectoryInfo In subdir.GetDirectories
            GetNewFilesEx(di, files)
        Next
    End Sub
End Class

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Betriebssystem: Schrott (Vista)
Entwicklungsumgebung: VS 2008