Invalid archive when using GZipStream

[Craig Buchanan]

when i try to open a file that has been compressed with GZipStream (source
from microsoft's 101 Samples for Visual Studio 2005), i get an "invalid
archive" message from winzip, zipgenius and xp's compressed folder app.
using DeflateStream resulted in the same error.

am i missing something simple?

thanks,

Craig Buchanan

<code>
Public Sub CompressFile(By Val sourceFile As String, ByVal destinationFile As
String)
' make sure the source file is there
If File.Exists(sou rceFile) = False Then
Throw New FileNotFoundExc eption
End If
' Create the streams and byte arrays needed
Dim buffer As Byte() = Nothing
Dim sourceStream As FileStream = Nothing
Dim destinationStre am As FileStream = Nothing
Dim compressedStrea m As GZipStream = Nothing
'Dim compressedStrea m As DeflateStream = Nothing
Try
' Read the bytes from the source file into a byte array
sourceStream = New FileStream(sour ceFile, FileMode.Open, FileAccess.Read ,
FileShare.Read)
' Read the source stream values into the buffer
buffer = New Byte(sourceStre am.Length) {}
Dim checkCounter As Integer = sourceStream.Re ad(buffer, 0, buffer.Length)
' Open the FileStream to write to
destinationStre am = New FileStream(dest inationFile, FileMode.OpenOr Create,
FileAccess.Writ e)
' Create a compression stream pointing to the destiantion stream
compressedStrea m = New GZipStream(dest inationStream,
CompressionMode .Compress, True)
'compressedStre am = New DeflateStream(d estinationStrea m,
CompressionMode .Compress, True)
'Now write the compressed data to the destination file
compressedStrea m.Write(buffer, 0, buffer.Length)
Catch ex As ApplicationExce ption
MessageBox.Show (ex.Message, "An Error occured during compression",
MessageBoxButto ns.OK, MessageBoxIcon. Error)
Finally
' Make sure we allways close all streams
If Not (sourceStream Is Nothing) Then
sourceStream.Cl ose()
End If
If Not (compressedStre am Is Nothing) Then
compressedStrea m.Close()
End If
If Not (destinationStr eam Is Nothing) Then
destinationStre am.Close()
End If
End Try
End Sub
</code>