VB.NET

Merge ZIP Archives Using AppendZip

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This example demonstrates how to use the AppendZip method to append all entries from one ZIP archive into another ZIP archive.

The AppendZip method reads the entries from an existing ZIP file in the local filesystem and appends them to the current in-memory Zip object.

This is useful for:

• Merging multiple ZIP archives into a single ZIP
• Adding the contents of a previously created ZIP archive
• Building larger ZIP archives from smaller ZIP files

The appended entries are not written to the output ZIP until a Write* method is called.

Suppose the ZIP archive reports.zip contains:

reports/january.pdf
reports/february.pdf

And suppose the ZIP archive images.zip contains:

images/logo.png
images/banner.jpg

After calling AppendZip for both ZIP files and writing the final ZIP archive, the resulting ZIP will contain:

reports/january.pdf
reports/february.pdf
images/logo.png
images/banner.jpg

te> VB.NET

Dim success As Boolean = False

' --------------------------------------------------------------------------------
' Note: The AppendZip method is currently not working and will be fixed in v11.5.0
' --------------------------------------------------------------------------------
Dim zip As New Chilkat.Zip

success = zip.NewZip("merged.zip")
If (success = False) Then
    Debug.WriteLine(zip.LastErrorText)
    Exit Sub
End If


' Append all entries from reports.zip.
success = zip.AppendZip("c:/zips/reports.zip")
If (success = False) Then
    Debug.WriteLine(zip.LastErrorText)
    Exit Sub
End If


' Append all entries from images.zip.
success = zip.AppendZip("c:/zips/images.zip")
If (success = False) Then
    Debug.WriteLine(zip.LastErrorText)
    Exit Sub
End If


' Additional entries can still be added.
success = zip.AddString("readme.txt","Merged ZIP archive","utf-8")
If (success = False) Then
    Debug.WriteLine(zip.LastErrorText)
    Exit Sub
End If


' Write the final ZIP archive.
success = zip.WriteZipAndClose()
If (success = False) Then
    Debug.WriteLine(zip.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("ZIP archive created successfully.")