Imports System.IO
Imports System.IO.Compression
 
Public Class Form1
    Private QuellDatei As String = "Beispiel1.txt"
    Private KompDatei As String = "Beispiel.zip"
    Private ZielDatei As String = "Beispiel2.txt"
 
    Private fileBytes() As Byte = Nothing
 
    ' Quelldatei in Puffer-Array einlesen:
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        Dim strm1 As New FileStream(QuellDatei, FileMode.Open)
        Dim len As Integer = CType(strm1.Length, Integer)
        ReDim fileBytes(len)
        strm1.Read(fileBytes, 0, fileBytes.Length)
        strm1.Close()
    End Sub
 
    ' Datei komprimieren:
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button2.Click
        Dim strm2 As New FileStream(KompDatei, FileMode.Create)
        Dim compStrm As New GZipStream(strm2, CompressionMode.Compress)
        compStrm.Write(fileBytes, 0, fileBytes.Length)
        compStrm.Flush()           ' internen Puffer leeren
        compStrm.Close()
        strm2.Close()
    End Sub
 
    ' Datei dekomprimieren:
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button3.Click
        Dim strm3 As New FileStream(KompDatei, FileMode.Open)
        Dim decompStrm As New GZipStream(strm3, CompressionMode.Decompress)
        Dim reader As New StreamReader(decompStrm)
        File.WriteAllText(ZielDatei, reader.ReadToEnd())
        reader.Close()
        strm3.Close()
    End Sub
End Class