Private Sub bnStart_Click(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles bnStart.Click
Dim sourceDir As String = txtPathFrom.Text.Trim()
sourceDir.Length = 0 Then
MesageBox.Show("Bitte den Quell-Pfad überprüfen!")
Return
Else
If Not Directory.Exists(sourceDir) Then
MessageBox.Show(sourceDir, "Quell-Pfad nicht gefunden!")Return
End If
End If
Dim targetName As String = txtPathTo.Text.Trim()
If targetName.Length = 0 Then
MessageBox.Show("Kein Datei Name angegeben!", "ZIP Datei Fehler!")
Return
End If
Dim astrFileNames() As String = Directory.GetFiles(sourceDir)
Dim strmZipOutputStream As ZipOutputStream
strmZipOutputStream = New ZipOutputStream(File.Create(targetName))
strmZipOutputStream.SetLevel(9)
Dim strFile As String
For Each strFile In astrFileNames
Dim strmFile As FileStream = File.OpenRead(strFile)
Dim abyBuffer(strmFile.Length - 1) As Byte
strmFile.Read(abyBuffer, 0, abyBuffer.Length)
Dim objZipEntry As ZipEntry = New ZipEntry(strFile)
objZipEntry.DateTime = DateTime.Now
objZipEntry.Size = strmFile.Length
strmFile.Close()
strmZipOutputStream.PutNextEntry(objZipEntry)
strmZipOutputStream.Write(abyBuffer, 0, abyBuffer.Length)
Next
strmZipOutputStream.Finish()
strmZipOutputStream.Close()
MessageBox.Show("Backup fertiggestellt!")
End Sub