(VB.NET) Remove an Entry from an Existing ZIP Using DeleteEntry

This example demonstrates how to use the DeleteEntry method to remove a file from an existing ZIP archive.

The example:

• Creates a ZIP archive containing three text files
• Opens the ZIP archive for modification
• Finds and deletes one entry
• Writes the modified ZIP archive to a new filename

Suppose the original ZIP archive contains:

a.txt
b.txt
c.txt

After deleting b.txt, the modified ZIP archive contains:

a.txt
c.txt

The entry is removed only from the in-memory ZIP object until a Write* method is called.

Note: This example requires Chilkat v11.0.0 or greater.

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Dim success As Boolean = False

success = False

' ------------------------------------------------------------
' First create a ZIP archive containing three text files.

Dim zip As New Chilkat.Zip

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


Dim charset As String = "utf-8"

success = zip.AddString("a.txt","Contents of file A",charset)
If (success = False) Then
    Debug.WriteLine(zip.LastErrorText)
    Exit Sub
End If


success = zip.AddString("b.txt","Contents of file B",charset)
If (success = False) Then
    Debug.WriteLine(zip.LastErrorText)
    Exit Sub
End If


success = zip.AddString("c.txt","Contents of file C",charset)
If (success = False) Then
    Debug.WriteLine(zip.LastErrorText)
    Exit Sub
End If


' Write the ZIP archive to disk.
' 
' The ZIP now contains:
' 
'     a.txt
'     b.txt
'     c.txt
' 
success = zip.WriteZipAndClose()
If (success = False) Then
    Debug.WriteLine(zip.LastErrorText)
    Exit Sub
End If


' ------------------------------------------------------------
' Open the existing ZIP archive for modification.

Dim zip2 As New Chilkat.Zip

success = zip2.OpenZip("original.zip")
If (success = False) Then
    Debug.WriteLine(zip2.LastErrorText)
    Exit Sub
End If


' Find the entry named "b.txt".
Dim entry As New Chilkat.ZipEntry

success = zip2.EntryOf("b.txt",entry)
If (success = False) Then
    Debug.WriteLine(zip2.LastErrorText)
    Exit Sub
End If


' Remove the entry from the in-memory ZIP object.
' 
' At this point, the original ZIP file on disk is unchanged.
' The deletion takes effect only after WriteZip or
' WriteZipAndClose is called.
success = zip2.DeleteEntry(entry)
If (success = False) Then
    Debug.WriteLine(zip2.LastErrorText)
    Exit Sub
End If


' Write the modified ZIP archive to a new file.
zip2.FileName = "modified.zip"

success = zip2.WriteZipAndClose()
If (success = False) Then
    Debug.WriteLine(zip2.LastErrorText)
    Exit Sub
End If


' The modified ZIP now contains:
' 
'     a.txt
'     c.txt
' 

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