vbnet Code:
  1. Imports System.IO.Compression
  2. Imports System.IO
  3.  
  4. Public Class FileCompression
  5.     Public Shared Sub CompressFile(ByVal sourceFile As String, ByVal destFile As String)
  6.  
  7.         Dim destStream As New FileStream(destFile, FileMode.Create, FileAccess.Write, FileShare.Read)
  8.         Dim srcStream As New FileStream(sourceFile, FileMode.Open, FileAccess.Read, FileShare.Read)
  9.         Dim gz As New GZipStream(destStream, CompressionMode.Compress)
  10.  
  11.         Dim bytesRead As Integer
  12.         Dim buffer As Byte() = New Byte(10000) {}
  13.  
  14.         bytesRead = srcStream.Read(buffer, 0, buffer.Length)
  15.  
  16.         While bytesRead <> 0
  17.             gz.Write(buffer, 0, bytesRead)
  18.  
  19.             bytesRead = srcStream.Read(buffer, 0, buffer.Length)
  20.         End While
  21.  
  22.         gz.Close()
  23.         destStream.Close()
  24.         srcStream.Close()
  25.     End Sub
  26.  
  27.     Public Shared Sub DecompressFile(ByVal sourceFile As String, ByVal destFile As String)
  28.  
  29.         Dim destStream As New FileStream(destFile, FileMode.Create, FileAccess.Write, FileShare.Read)
  30.         Dim srcStream As New FileStream(sourceFile, FileMode.Open, FileAccess.Read, FileShare.Read)
  31.         Dim gz As New GZipStream(srcStream, CompressionMode.Decompress)
  32.  
  33.         Dim bytesRead As Integer
  34.         Dim buffer As Byte() = New Byte(10000) {}
  35.  
  36.         bytesRead = gz.Read(buffer, 0, buffer.Length)
  37.  
  38.         While bytesRead <> 0
  39.             destStream.Write(buffer, 0, bytesRead)
  40.  
  41.             bytesRead = gz.Read(buffer, 0, buffer.Length)
  42.         End While
  43.  
  44.         gz.Close()
  45.         destStream.Close()
  46.         srcStream.Close()
  47.  
  48.  
  49.     End Sub
  50. End Class

Usage:-
vbnet Code:
  1. '
  2.         'Compresses "example.txt" into "example.zip"
  3.         FileCompression.CompressFile("C:\example.txt", "example.zip")
  4.  
  5.         'Decompresses "example.zip" back into "example.txt"
  6.         FileCompression.DecompressFile("C:\example.zip", "C:\example.txt")