Append Files to Existing Zip w/out Rewriting Entire Zip

Demonstrates how to use the QuickAppend method to append files to an existing .zip archive. This method works by editing the existing .zip -- it does not rewrite or recompress the contents of the existing .zip. It is the fastest way to append additional files 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.

Download Chilkat .NET for 2.0 / 3.5 Framework

Download Chilkat .NET for 1.0 / 1.1 Framework

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


'  The NewZip method only initializes the Zip object -- it does
'  not create or write a .zip file.
success = zip.NewZip("notUsed.zip")
If (success <> true) Then
    MsgBox(zip.LastErrorText)
    Exit Sub
End If



'  Add a reference to a file.  This is the file that will
'  be added to a pre-existing .zip archive.
'  Note: this does not read or compress the file contents --
'  it simply adds a reference to the zip object.
Dim saveExtraPath As Boolean
saveExtraPath = false
success = zip.AppendOneFileOrDir("something.dat",saveExtraPath)
If (success <> true) Then
    MsgBox(zip.LastErrorText)
    Exit Sub
End If


'  Appends the contents of the zip object to the preExisting.zip
'  zip archive.  preExisting.zip is opened, and the files
'  referenced by this zip object are streamed in, compressed,
'  and appended to the end of the archive.
success = zip.QuickAppend("preExisting.zip")
If (success <> true) Then
    MsgBox(zip.LastErrorText)
    Exit Sub
End If


MsgBox("Success!")


'  Note: Additional files, directory trees, or in-memory data
'  can be appended by calling AppendOneFileOrDir, AppendFiles,
'  AppendString, AppendData, etc. multiple times.
'  Whatever files and/or in-memory data that are referenced by
'  this zip object will be appended to preExisting.zip when
'  QuickAppend is called.