Merge Zip Archives - Append .zip onto another .zip

Download: Chilkat .NET Assemblies

Demonstrates how to use the QuickAppend method to append the contents of one .zip archive to another .zip archive. This method works by editing the target .zip -- it does not rewrite the target .zip. It does not recompress (or re-encrypt) the data in either archive. It is the fastest way to append additional files or data to a pre-existing large .zip archive. Note: The QuickAppend method is new and available in the pre-release downloads, or in official releases dated after 6-October-2007.

Dim zip As New Chilkat.Zip()

Dim success As Boolean

'  Any string unlocks the component for the 1st 30-days.
success = zip.UnlockComponent("Anything for 30-day trial")
If (success <> true) Then
    MsgBox(zip.LastErrorText)
    Exit Sub
End If


'  Open the .zip archive that is to be appended to target.zip.
'  You should open the smaller of the two .zip archives here --
'  to minimize the amount of data to be copied.  When the .zips
'  are merged, nothing is recompressed.  The compressed (and
'  possibly encrypted) data is simply appended to the end
'  of the target .zip.
success = zip.OpenZip("zipToBeAppended.zip")
If (success <> true) Then
    MsgBox(zip.LastErrorText)
    Exit Sub
End If


'  Appends the contents of this zip object to the target.zip
'  archive.  After calling QuickAppend, target.zip will contain
'  both its original contents as well as the contents of
'  "zipToBeAppended.zip".
success = zip.QuickAppend("target.zip")
If (success <> true) Then
    MsgBox(zip.LastErrorText)
    Exit Sub
End If


MsgBox("Success!")