Zip Classic ASP Reference Documentation

Zip

Current Version: 11.6.0

Chilkat.Zip

Create, read, modify, encrypt, and extract ZIP archives.

Chilkat.Zip provides a comprehensive API for working with ZIP archives from files, memory, BinData, embedded resources, and Windows self-extracting EXEs. It can create new archives, open existing ZIPs, add files or in-memory data, inspect entries, extract selectively, and write the final archive to disk or memory.

Create ZIP archives

Add files, directories, strings, byte arrays, BinData, and StringBuilder content.

Open ZIPs from many sources

Open archives from disk, memory, BinData, embedded Windows resources, or Chilkat-created self-extracting EXEs.

Control stored paths

Use options such as AppendFromDir, DiscardPaths, PathPrefix, and saveExtraPath.

Extract selectively

Extract all files, matching entries, newer files, or flatten all output into a single directory.

Encryption support

Work with WinZip-compatible AES encryption and legacy Zip 2.0 password protection.

Large archive support

ZIP64 is used automatically when older ZIP limits are exceeded.

Important: Many methods update the in-memory ZIP object first. The archive is not written until a method such as WriteZip, WriteZipAndClose, WriteBd, or WriteToMemory is called.

Object Creation

set zip = Server.CreateObject("Chilkat.Zip")

' ... use zip ...

set zip = Nothing

Classic ASP creates Chilkat objects with Server.CreateObject. The registered Chilkat ActiveX must match the bitness of the IIS application pool: a pool with Enable 32-Bit Applications set to True needs the 32-bit ActiveX, otherwise the 64-bit ActiveX. To bind to a specific major version of Chilkat, append the major version number to the ProgID, such as Server.CreateObject("Chilkat.Zip.11") for Chilkat v11.*.*.

VBScript requires set when assigning an object, so the signatures on this page show set x = obj.Method(...) for methods that return a Chilkat object; test the result with Is Nothing, since a method that fails to return an object returns Nothing. A method with no return value is called as a statement without parentheses (obj.Method arg1, arg2). Boolean properties, arguments and return values are integers in the ActiveX: pass 1 or 0, and test success with = 1. Byte arrays are Variant arrays and can be sent with Response.BinaryWrite. Asynchronous (*Async) methods and event callbacks are not used from Classic ASP.

Properties

AbortCurrent
zip.AbortCurrent ' Long
Introduced in version 9.5.0.58

Stops the currently executing operation when set to 1.

  • Used to cancel long-running operations such as compression or extraction.
  • Can be triggered from another thread.
  • Automatically resets to 0 after the operation stops.

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AppendFromDir
zip.AppendFromDir ' String

Specifies a base directory when adding files to the ZIP.

  • This portion of the path is not included in stored ZIP entry paths.
  • Useful for controlling relative paths inside the archive.

For example, to add all files under c:/abc/123/myAppDir, this property could be set to c:/abc/123, and myAppDir/* would be passed to AppendFiles.

The path stored in the ZIP would begin with myAppDir/.

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AutoRun
zip.AutoRun ' String

(Windows only, for creating self-extracting EXE's)

Specifies the name of an executable inside a self-extracting EXE that runs automatically after extraction.

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AutoRunParams
zip.AutoRunParams ' String

(Windows only, for creating self-extracting EXE's)

Command-line arguments passed to the AutoRun executable.

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AutoTemp
zip.AutoTemp ' Long

(Windows only, for creating self-extracting EXE's)

If 1, the EXE being created will automatically select and create a temporary directory for unzipping.

This property is often used together with AutoRun to create a self-extracting EXE that automatically unzips to a temporary directory and runs a setup program, such as setup.exe, without user interaction.

Note: To create a self-extracting EXE with no user interaction, set the following properties:

ExeSilentProgress = 0
ExeNoInterface = 1
ExeFinishNotifier = 0

The default value is 0.

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CaseSensitive
zip.CaseSensitive ' Long

Controls whether filename matching is case-sensitive.

  • Affects methods such as EntryMatching and UnzipMatching.
  • Default: 0

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ClearArchiveAttribute
zip.ClearArchiveAttribute ' Long

(Windows only)

If 1, clears the Windows archive attribute after files are successfully added to the ZIP.

The archive attribute indicates that a file has changed since the last backup.

The default value is 0.

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ClearReadOnlyAttr
zip.ClearReadOnlyAttr ' Long

If 1, removes the read-only attribute from extracted files.

If 0, the read-only attribute remains unchanged.

The default value is 0.

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Comment
zip.Comment ' String

Sets or retrieves the global ZIP file comment.

The default value is the empty string.

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DebugLogFilePath
zip.DebugLogFilePath ' String

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

  • A timeout property set to 0, indicating an infinite timeout.
  • A hang occurring within an event callback in the application code.
  • An internal bug in the Chilkat code causing the hang.

More Information and Examples
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DecryptPassword
zip.DecryptPassword ' String

Password used to extract encrypted ZIP archives.

  • Required to unzip encrypted entries.
  • Encrypted ZIP files may still be opened without a password, but their contents cannot be extracted until the correct password is provided.

The default value is the empty string.

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DiscardPaths
zip.DiscardPaths ' Long

If 1, removes all directory path information when adding files.

Only filenames are stored in the ZIP.

The default value is 0.

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Encryption
zip.Encryption ' Long

Specifies encryption mode:

  • 0 → No encryption
  • 4 → WinZip-compatible AES encryption

Important: Encryption and PasswordProtect are mutually exclusive.

If PasswordProtect = 1, then Encryption should be 0.

The default value is 0.

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EncryptKeyLength
zip.EncryptKeyLength ' Long

Specifies the AES encryption key length.

  • Valid values: 128, 192, or 256

The default value is 128.

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EncryptPassword
zip.EncryptPassword ' String

Password used when creating encrypted ZIP archives.

The default value is the empty string.

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ExeDefaultDir
zip.ExeDefaultDir ' String

(Windows only, for creating self-extracting EXE's)

Default extraction directory shown in the self-extracting EXE user interface.

The default value is the empty string.

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ExeFinishNotifier
zip.ExeFinishNotifier ' Long

(Windows only, for creating self-extracting EXE's)

If 1, displays a completion dialog after extraction finishes.

The default value is 0.

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ExeIconFile
zip.ExeIconFile ' String

(Windows only, for creating self-extracting EXE's)

Path to an .ico file used as the EXE icon.

This feature is only available when the application creating the EXE is 32-bit.

The default value is the empty string.

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ExeNoInterface
zip.ExeNoInterface ' Long

(Windows only, for creating self-extracting EXE's)

If 1, runs the self-extracting EXE without displaying the main user interface.

The default value is 0.

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ExeSilentProgress
zip.ExeSilentProgress ' Long

(Windows only, for creating self-extracting EXE's)

Controls whether a progress dialog is shown during extraction.

If ExeNoInterface = 0, the progress bar appears within the main dialog and this property has no effect.

The default value is 0.

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ExeTitle
zip.ExeTitle ' String

(Windows only, for creating self-extracting EXE's)

Title displayed in the self-extracting EXE dialog.

The default value is the empty string.

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ExeUnzipCaption
zip.ExeUnzipCaption ' String

(Windows only, for creating self-extracting EXE's)

Caption text displayed in the self-extracting EXE dialog.

The default value is the empty string.

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ExeUnzipDir
zip.ExeUnzipDir ' String

(Windows only, for creating self-extracting EXE's)

Specifies a predefined extraction directory.

  • Supports environment variables such as %TEMP%.
  • UNC paths are not supported.

The default value is the empty string.

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ExeWaitForSetup
zip.ExeWaitForSetup ' Long

If 1, waits for the AutoRun executable to finish before exiting.

If 0, the self-extracting EXE may exit before the AutoRun executable completes.

The default value is 1.

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ExeXmlConfig
zip.ExeXmlConfig ' String

Allows for an XML config document to be used to specify all possible options for self-extracting EXEs. This property is a string containing the XML config document.

The XML should have this format:

<SfxConfig>
<ErrPwdTitle>Title for incorrect password dialog</ErrPwdTitle>
<ErrPwdCaption>Caption for incorrect password dialog</ErrPwdCaption>
<FinOkBtn>Text on finish notifier button</FinOkBtn>
<PwdOkBtn>Text on password challenge dialog's "OK" button.</PwdOkBtn>
<PwdCancelBtn>Text on password challenge dialog's Cancel button.</PwdCancelBtn>
<ErrInvalidPassword>Incorrect password error message.</ErrInvalidPassword>
<MainUnzipBtn>Text on main dialog's unzip button. Note: The MainUnzipLabel must also be set for this to take effect.</MainUnzipBtn>
<MainCloseBtn>Text on main dialog's quit/exit button. Note: The MainUnzipLabel must also be set for this to take effect.</MainCloseBtn>
<MainBrowseBtn>Text on main dialog's browse-for-directory button. Note: The MainUnzipLabel must also be set for this to take effect.</MainBrowseBtn>
<MainUnzipLabel>Caption displayed in main dialog.</MainUnzipLabel>
<AutoTemp>0 or 1 (Maps to the AutoTemp property)</AutoTemp>
<Cleanup>0 or 1 (If 1, extracted files are deleted after the SetupExe is run.)</Cleanup>
<Debug>0 or 1 (If 1, the EXE will not extract any files.)</Debug>
<Verbose>0 or 1 (If 1, verbose information is written to the log.)</Verbose>
<ShowFin>0 or 1 (Maps to the ExeFinishNotifier property)</ShowFin>
<ShowMain>0 or 1 (Maps to the ExeNoInterface property)</ShowMain>
<ShowProgress>0 or 1 (Maps to the ExeSilentProgress property)</ShowProgress>
<WaitForSetup>0 or 1 (Maps to the ExeWaitForSetup property)</WaitForSetup>
<Encryption>0 or 1 (1 = Yes, 0 = No)</Encryption>
<KeyLength>128|192|256</KeyLength>
<SetupExe>EXE to run after extracting. (Maps to the AutoRun property)</SetupExe>
<UnzipDir>Pre-defined unzip directory. (Maps to the ExeUnzipDir property. UNC paths, such as \\servername\path, are not supported.)</UnzipDir>
<DefaultDir>Default unzip directory to appear in the main dialog. (Maps to the ExeDefaultDir property)</DefaultDir>
<IconFile>Icon file to be used (Maps to the ExeIconFile property)</IconFile>
<MainTitle>Maps to the ExeTitle property.</MainTitle>
<MainCaption>Maps to the ExeUnzipCaption property.</MainCaption>
<FinTitle>Title for the finish notifier dialog.</FinTitle>
<FinCaption>Caption for the finish notifier dialog.</FinCaption>
<ProgressTitle>Title for the progress dialog.</ProgressTitle>
<ProgressCaption>Caption for the progress dialog.</ProgressCaption>
<PwTitle>Title for the password challenge dialog.</PwTitle>
<PwCaption>Caption for the password challenge dialog.</PwCaption>
</SfxConfig>

A self-extracting EXE can be run from the command line with the -log {logFilePath} option to create a log with information for debugging.

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FileCount
zip.FileCount ' Long (read-only)

Number of files in the ZIP, excluding directory entries.

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FileName
zip.FileName ' String

Path of the ZIP file to be written or overwritten.

The default value is the empty string.

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HasZipFormatErrors
zip.HasZipFormatErrors ' Long (read-only)

Indicates whether minor ZIP format problems were detected when opening the ZIP archive.

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IgnoreAccessDenied
zip.IgnoreAccessDenied ' Long

If 1, files that cannot be read, written, or created due to filesystem permission errors are skipped.

If 0, any access-denied error causes the ZIP operation to fail.

The default value is 1.

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LastBinaryResult
zip.LastBinaryResult ' Variant (read-only)

This property is mainly used in SQL Server stored procedures to retrieve binary data from the last method call that returned binary data. It is only accessible if Chilkat.Global.KeepBinaryResult is set to 1. This feature allows for the retrieval of large varbinary results in an SQL Server environment, which has restrictions on returning large data via method calls, though temp tables can handle binary properties.

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LastErrorHtml
zip.LastErrorHtml ' String (read-only)

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorText
zip.LastErrorText ' String (read-only)

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorXml
zip.LastErrorXml ' String (read-only)

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastMethodSuccess
zip.LastMethodSuccess ' Long

Indicates the success or failure of the most recent method call: 1 means success, 0 means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

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LastStringResult
zip.LastStringResult ' String (read-only)

In SQL Server stored procedures, this property holds the string return value of the most recent method call that returns a string. It is accessible only when Chilkat.Global.KeepStringResult is set to TRUE. SQL Server has limitations on string lengths returned from methods and properties, but temp tables can be used to access large strings.

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LastStringResultLen
zip.LastStringResultLen ' Long (read-only)

The length, in characters, of the string contained in the LastStringResult property.

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MaxDate
zip.MaxDate ' String
Introduced in version 10.0.0

Maximum last-modified timestamp for files processed during add or extract operations.

Files having modification timestamps later than this value are skipped.

Supports ISO 8601 date/time formats, including:

  • YYYY-MM-DD
    Example: 2024-07-31
  • YYYY-MM-DDTHH:MM:SS±HH:MM
    Example: 2024-07-31T12:34:56+02:00
  • YYYY-MM-DDTHH:MM:SSZ
    Example: 2024-07-31T12:34:56Z

The default value is the empty string, meaning no maximum date restriction.

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MaxUncompressSize
zip.MaxUncompressSize ' Long
Introduced in version 9.5.0.96

Prevents extraction of files larger than the specified uncompressed size.

A value of 0 means no size limit.

The default value is 0.

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MinDate
zip.MinDate ' String
Introduced in version 10.0.0

Minimum last-modified timestamp for files processed during add or extract operations.

Supports ISO 8601 date/time formats, including:

  • YYYY-MM-DD
    Example: 2024-07-31
  • YYYY-MM-DDTHH:MM:SS±HH:MM
    Example: 2024-07-31T12:34:56+02:00
  • YYYY-MM-DDTHH:MM:SSZ
    Example: 2024-07-31T12:34:56Z

The default value is the empty string, meaning no minimum date restriction.

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NumEntries
zip.NumEntries ' Long (read-only)

Total number of entries in the ZIP, including both files and directories.

More Information and Examples
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OemCodePage
zip.OemCodePage ' Long

Specifies the OEM code page used for ZIP filename encoding.

Defaults to the OEM code page of the current computer.

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OverwriteExisting
zip.OverwriteExisting ' Long

If 1, existing files are overwritten during extraction.

The default value is 1.

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PasswordProtect
zip.PasswordProtect ' Long

Indicates whether the ZIP uses legacy Zip 2.0 password protection.

This property is set automatically when a ZIP archive is opened by any of the Open* methods, such as OpenZip, OpenFromMemory, OpenBd, and related methods.

Important: PasswordProtect and Encryption are mutually exclusive.

If PasswordProtect = 1, then Encryption should be 0.

The default value is 0.

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PathPrefix
zip.PathPrefix ' String

Gets or sets a path prefix that is prepended to ZIP entry paths for files appended from the local filesystem.

This is useful when you want all extracted files to appear under a specific subdirectory.

This property affects only the following methods:

  • AppendFiles
  • AppendFilesEx
  • AddFile
  • AppendOneFileOrDir

The PathPrefix value is prepended to the stored ZIP path for each appended filesystem file.

For example, set PathPrefix to subdir/ so that files are stored in the ZIP with subdir/ prepended to their paths. When extracted, the files will be placed under the subdir directory.

This property does not affect entries added entirely from memory, such as entries added using:

  • AddString
  • AddData
  • AddBd
  • AddSb

For in-memory entries, the ZIP entry path is determined solely by the filename/path argument passed to the method.

The default value is the empty string.

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PwdProtCharset
zip.PwdProtCharset ' String
Introduced in version 9.5.0.73

Specifies the character encoding used to convert the decrypt password into its binary byte representation for legacy password-protected ZIP archives that use Zip 2.0 encryption.

The default value is ansi.

Other possible values include:

  • cp850
  • cp437
  • Any supported Windows or OEM code page listed at the link below.

This property applies only to older Zip 2.0 password protection and is not used for AES-encrypted ZIP archives.

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TempDir
zip.TempDir ' String

Directory used for temporary files during ZIP operations.

When overwriting an existing ZIP file, a temporary file is used to avoid corrupting the original ZIP if an error occurs.

The default value depends on the runtime environment.

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UncommonOptions
zip.UncommonOptions ' String
Introduced in version 9.5.0.84

Advanced options for uncommon scenarios.

  • ForceZip64 → Forces ZIP64 format even when not required.

The default value is the empty string.

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VerboseLogging
zip.VerboseLogging ' Long

If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
zip.Version ' String (read-only)

Version of the component/library, such as "10.1.0"

More Information and Examples
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Zipx
zip.Zipx ' Long

If 1, creates ZIPX archives using the most appropriate compression method for each file.

The default value is 0.

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ZipxDefaultAlg
zip.ZipxDefaultAlg ' String

Default compression algorithm used when creating ZIPX archives.

  • Possible values include:
    • deflate
    • ppmd
    • lzma
    • bzip2
    • deflate64

The default value is deflate.

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Methods

AddBd
success = zip.AddBd(pathInZip, bd) ' Long (1/0)
Introduced in version 11.0.0

Adds the contents of a BinData object as a new entry in the ZIP archive.

  • pathInZip specifies the filename and optional directory path stored within the ZIP.
  • The bytes contained in bd become the contents of the ZIP entry.
  • The entry is added to the in-memory ZIP object and is not written to disk until WriteZip, WriteZipAndClose, WriteBd, or WriteToMemory is called.

Returns 1 for success, 0 for failure.

More Information and Examples
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AddEmpty
success = zip.AddEmpty(isDir, pathInZip) ' Long (1/0)
Introduced in version 11.0.0

Adds an empty file or directory entry to the ZIP archive.

  • If isDir = 1, an empty directory entry is created.
  • If isDir = 0, an empty file entry is created.
  • pathInZip specifies the path stored in the ZIP archive.

This method is useful when directory structure entries must exist even if no files are present.

Returns 1 for success, 0 for failure.

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AddEncoded
success = zip.AddEncoded(pathInZip, encoding, data) ' Long (1/0)
Introduced in version 11.0.0

Adds encoded binary data as a ZIP entry.

  • encoding specifies how data is encoded.
  • Common encodings include base64 and hex.
  • The decoded binary bytes become the contents of the ZIP entry.

This method is useful when binary data already exists in textual encoded form.

Returns 1 for success, 0 for failure.

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AddFile
success = zip.AddFile(localPath, saveExtraPath) ' Long (1/0)
Introduced in version 11.0.0

Adds a file or directory from the local filesystem to the ZIP archive.

  • If localPath is an absolute path and saveExtraPath = 1, the stored ZIP path includes the relative directory structure.
  • If saveExtraPath = 0, only the filename is stored.
  • If localPath is already relative, the relative path is stored as-is regardless of saveExtraPath.

This method adds a reference to the file or directory in the local filesystem. The file data is not immediately read or compressed.

The actual file contents are consumed only when a Write* method is called, such as:

  • WriteZip
  • WriteZipAndClose
  • WriteBd
  • WriteToMemory

This allows files and data entries to be accumulated in the in-memory ZIP object prior to writing the final ZIP archive.

Returns 1 for success, 0 for failure.

More Information and Examples
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AddNoCompressExtension
zip.AddNoCompressExtension fileExtension

Adds a file extension to the internal "no-compression" list.

Files having these extensions are stored without compression because they are already compressed or because compression would provide little benefit.

For example:

  • .zip
  • .jpg
  • .png
  • .gz

The extension may be specified with or without the leading dot.

Additional extensions remain active for the lifetime of the Zip object unless removed with RemoveNoCompressExtension.

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AddSb
success = zip.AddSb(pathInZip, sb, charset) ' Long (1/0)
Introduced in version 11.0.0

Adds the contents of a StringBuilder object as a text entry in the ZIP archive.

  • The text is converted to bytes using the specified charset.
  • pathInZip specifies the filename stored in the ZIP.

Returns 1 for success, 0 for failure.

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AddString
success = zip.AddString(pathInZip, content, charset) ' Long (1/0)
Introduced in version 11.0.0

Adds a string as a text file entry in the ZIP archive.

  • The string is converted to bytes using the specified charset.
  • pathInZip specifies the path stored within the ZIP archive.

This method is useful for dynamically generating text files directly in memory.

Returns 1 for success, 0 for failure.

More Information and Examples
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AppendFiles
success = zip.AppendFiles(filePattern, recurse) ' Long (1/0)

Adds one or more files matching a wildcard pattern.

  • The wildcard character * matches zero or more characters.
  • If recurse = 1, subdirectories are processed recursively.
  • If recurse = 0, only the current directory is searched.

For example:

AppendFiles("c:/temp/*.txt", 0)

This method only updates the in-memory ZIP object. The ZIP file itself is not written until a Write* method is called.

Returns 1 for success, 0 for failure.

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AppendFilesEx
success = zip.AppendFilesEx(filePattern, recurse, saveExtraPath, archiveOnly, includeHidden, includeSystem) ' Long (1/0)

Advanced version of AppendFiles with additional filtering and path options.

  • saveExtraPath controls whether the extra leading path information from the filePattern is preserved in the ZIP.
  • archiveOnly applies only on Windows and limits processing to files having the archive attribute set.
  • includeHidden controls whether hidden files are included.
  • includeSystem controls whether files with the System attribute are included.

This method adds references to files in the in-memory ZIP object. No ZIP file is written until a Write* method is called.

Returns 1 for success, 0 for failure.

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AppendZip
success = zip.AppendZip(zipPath) ' Long (1/0)

Note: This method is currently not working and will be fixed in v11.5.0

Adds all entries from another existing ZIP archive into the current ZIP object.

The zipPath argument specifies the path of a ZIP file located in the local filesystem.

All entries from the specified ZIP archive are appended to the current in-memory ZIP object.

The ZIP archive itself is not rewritten until a Write* method is called.

This method is useful for merging the contents of multiple ZIP archives into a single ZIP.

Returns 1 for success, 0 for failure.

More Information and Examples
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CloseZip
zip.CloseZip

Closes the currently open ZIP archive and clears all entries from the Zip object.

This method has the same effect as calling NewZip without specifying a filename.

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DeleteEntry
success = zip.DeleteEntry(entry) ' Long (1/0)

Removes a ZIP entry from the current ZIP object.

The ZIP file itself is not rewritten until a Write* method is called.

Returns 1 for success, 0 for failure.

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EntryAt
success = zip.EntryAt(index, entry) ' Long (1/0)
Introduced in version 11.0.0

Retrieves the ZIP entry at the specified zero-based index.

  • The first entry is at index 0.
  • The matching entry is returned in the supplied ZipEntry object.

Returns 1 for success, 0 for failure.

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EntryById
success = zip.EntryById(id, entry) ' Long (1/0)
Introduced in version 11.0.0

Finds a ZIP entry by its unique EntryID.

The matching entry is returned in the supplied ZipEntry object.

Returns 1 for success, 0 for failure.

More Information and Examples
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EntryMatching
success = zip.EntryMatching(pattern, entry) ' Long (1/0)
Introduced in version 11.0.0

Finds the first ZIP entry whose stored path matches a wildcard pattern.

  • The wildcard character * matches zero or more characters.
  • The comparison is performed against the full stored ZIP path.

Returns 1 for success, 0 for failure.

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EntryOf
success = zip.EntryOf(pathInZip, entry) ' Long (1/0)
Introduced in version 11.0.0

Finds a ZIP entry whose stored path exactly matches pathInZip.

The matching entry is returned in the supplied ZipEntry object.

Returns 1 for success, 0 for failure.

More Information and Examples
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ExcludeDir
zip.ExcludeDir dirName

Adds a directory name to the exclusion list used by recursive append operations.

  • All directories having the specified name are skipped.
  • The comparison is case-insensitive.
  • Call multiple times to exclude multiple directory names.

This affects methods such as AppendFiles and AppendFilesEx.

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ExtractExe
success = zip.ExtractExe(exePath, dirPath) ' Long (1/0)
Introduced in version 9.5.0.44

Extracts files from a Chilkat-created self-extracting EXE.

  • Files are extracted into dirPath.
  • Subdirectories are automatically created as needed.
  • If the EXE is encrypted, DecryptPassword must be set before extraction.

Returns 1 for success, 0 for failure.

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GetDirectoryAsXML
str = zip.GetDirectoryAsXML() ' String

Returns the ZIP directory structure as an XML document.

The returned XML contains information about the entries currently contained within the ZIP archive, including files and directories.

This method is useful for inspecting ZIP contents without extracting files.

Returns the XML document as a string.

Returns Nothing on failure

More Information and Examples
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GetExeConfigParam
str = zip.GetExeConfigParam(name) ' String

(Windows only, for creating self-extracting EXE's)

Returns the value of a configuration parameter embedded within a self-extracting EXE.

The name argument should be one of the XML tag names described in the ExeXmlConfig property documentation.

For example:

  • MainTitle
  • MainCaption
  • SetupExe

Returns the parameter value as a string.

Returns Nothing on failure

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GetMaxUncompressedSize
str = zip.GetMaxUncompressedSize() ' String
Introduced in version 9.5.0.96

Returns the largest uncompressed file size contained within the ZIP archive.

The size is returned as a string rather than an integer because the value may exceed the range of a 32-bit integer.

This method is useful when:

  • Checking for extremely large files before extraction
  • Estimating required disk space
  • Detecting unusually large compressed entries

Returns the size as a decimal string.

Returns Nothing on failure

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IsNoCompressExtension
success = zip.IsNoCompressExtension(fileExtension) ' Long (1/0)

Checks whether a file extension is contained in the internal "no-compression" extension list.

Files having extensions in this list are stored without compression because they are typically already compressed.

The extension may be specified with or without the leading dot.

For example, both of the following are valid:

  • .jpg
  • jpg

Returns 1 if the extension exists in the list, otherwise returns 0.

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IsPasswordProtected
success = zip.IsPasswordProtected(zipPath) ' Long (1/0)

Checks whether a ZIP archive uses legacy Zip 2.0 password protection.

The zipPath argument specifies the path of a ZIP file in the local filesystem.

This method checks only for traditional Zip 2.0 password protection.

Returns 1 if the ZIP archive is password protected, otherwise returns 0.

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NewZip
success = zip.NewZip(zipPath) ' Long (1/0)

Initializes a new empty ZIP archive.

  • If another ZIP archive is currently open, it is closed.
  • All existing in-memory ZIP entries are discarded.
  • The FileName property is set to zipPath.

No ZIP file is actually created until a Write* method is called.

This method resets the Zip object to a clean empty state.

More Information and Examples
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OpenBd
success = zip.OpenBd(binData) ' Long (1/0)
Introduced in version 9.5.0.66

Opens a ZIP archive contained entirely within a BinData object.

This method allows ZIP archives to be processed entirely in memory without requiring a filesystem file.

When a ZIP archive is opened:

  • PasswordProtect is automatically set if legacy Zip 2.0 encryption is detected.
  • Encryption is automatically set if strong encryption is detected.
  • A value of 4 for Encryption indicates WinZip-compatible AES encryption.

Returns 1 for success, 0 for failure.

More Information and Examples
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OpenEmbedded
success = zip.OpenEmbedded(exeFilename, resourceName) ' Long (1/0)

(Windows only)

Opens a ZIP archive embedded as a resource within a Windows executable.

  • exeFilename specifies the EXE file path.
  • resourceName specifies the embedded resource name containing the ZIP data.

This method is useful when ZIP archives are packaged within Windows applications.

Returns 1 for success, 0 for failure.

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OpenFromByteData
success = zip.OpenFromByteData(byteData) ' Long (1/0)

Opens a ZIP archive from in-memory byte data.

When the ZIP archive is opened:

  • PasswordProtect is automatically set if legacy password protection is detected.
  • Encryption is automatically set if strong encryption is detected.
  • Encryption = 4 indicates AES encryption.

Returns 1 for success, 0 for failure.

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OpenFromMemory
success = zip.OpenFromMemory(inData) ' Long (1/0)

Opens a ZIP archive directly from in-memory binary data.

This allows ZIP processing without using filesystem files.

Typical use cases include:

  • ZIP data loaded from a database
  • ZIP data received from HTTP responses
  • ZIP data stored entirely in memory

When the ZIP archive is opened:

  • PasswordProtect is automatically set if Zip 2.0 encryption is detected.
  • Encryption is automatically set if strong encryption is detected.

Returns 1 for success, 0 for failure.

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OpenZip
success = zip.OpenZip(zipPath) ' Long (1/0)

Opens a ZIP archive from the local filesystem.

The zipPath argument specifies the path of the ZIP file to open.

Encrypted ZIP archives may be opened without providing a password, but encrypted entries cannot be extracted until the correct password is provided using DecryptPassword.

When the ZIP archive is opened:

  • PasswordProtect is automatically set if legacy Zip 2.0 encryption is detected.
  • Encryption is automatically set if strong encryption is detected.
  • Encryption = 4 indicates WinZip-compatible AES encryption.

Returns 1 for success, 0 for failure.

More Information and Examples
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QuickAppend
success = zip.QuickAppend(zipPath) ' Long (1/0)

Efficiently appends additional entries to an existing ZIP archive.

The zipPath argument specifies the path of an existing ZIP archive in the local filesystem.

This method avoids rewriting existing entries.

  • Existing ZIP entries remain unchanged.
  • New entries are appended to the end of the ZIP archive.
  • The ZIP central directory is updated accordingly.

This method is typically faster than rebuilding the entire ZIP archive.

Returns 1 for success, 0 for failure.

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RemoveNoCompressExtension
zip.RemoveNoCompressExtension fileExtension

Removes a file extension from the internal "no-compression" extension list.

After removal, files having this extension may be compressed normally.

The extension may be specified with or without the leading dot.

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SetCompressionLevel
zip.SetCompressionLevel level

Sets the compression level for all file and data entries currently contained within the ZIP object.

  • 0 → No compression
  • 9 → Maximum compression

The default compression level is 6.

Important: This method should be called after files or data entries have already been added to the ZIP object.

The compression level cannot be changed for mapped entries originating from an already-open ZIP archive.

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SetExclusions
zip.SetExclusions excludePatterns

Specifies a collection of wildcard exclusion patterns used when adding files to the ZIP archive.

Each pattern may use the wildcard character * to match zero or more characters.

Files matching any exclusion pattern are skipped.

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SetExeConfigParam
zip.SetExeConfigParam paramName, paramValue

(Windows only, for creating self-extracting EXE's)

Sets a configuration parameter embedded within a self-extracting EXE created by WriteExe or WriteExe2.

The paramName should be one of the XML configuration tag names described in the ExeXmlConfig property documentation.

For example:

SetExeConfigParam("MainUnzipBtn","Extract")

This changes the text displayed on the self-extractor's main unzip button.

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Unzip
n = zip.Unzip(dirPath) ' Long

Extracts all files and directories from the ZIP archive.

  • dirPath specifies the destination directory.
  • Subdirectories are automatically created as needed.

Returns the number of files extracted.

Returns -1 if a failure occurs.

More Information and Examples
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UnzipInto
n = zip.UnzipInto(dirPath) ' Long

Extracts all files into a single directory.

All directory path information stored within the ZIP archive is ignored.

If multiple files have the same filename, later extracted files overwrite earlier ones.

Returns the number of files extracted, or -1 on failure.

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UnzipMatching
n = zip.UnzipMatching(dirPath, pattern, verbose) ' Long

Extracts only entries whose stored paths match a wildcard pattern.

  • The wildcard character * matches zero or more characters.
  • If no wildcard is used, an exact filename match is required.

Subdirectories are automatically created as needed.

Returns the number of files extracted, or -1 on failure.

More Information and Examples
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UnzipMatchingInto
n = zip.UnzipMatchingInto(dirPath, pattern, verbose) ' Long

Extracts matching entries into a single directory while ignoring all stored ZIP path information.

Matching behavior is identical to UnzipMatching.

If duplicate filenames occur, later extracted files overwrite earlier ones.

Returns the number of files extracted, or -1 on failure.

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UnzipNewer
n = zip.UnzipNewer(dirPath) ' Long

Extracts only files that:

  • Do not already exist
  • Or have older modification timestamps than the ZIP entry

Subdirectories are automatically created as needed.

Returns the number of files extracted, or -1 on failure.

More Information and Examples
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VerifyPassword
success = zip.VerifyPassword() ' Long (1/0)

Verifies that the current DecryptPassword value is correct for the currently opened ZIP archive.

This method allows password validation before attempting extraction.

Returns 1 if the password is valid, otherwise returns 0.

More Information and Examples
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WriteBd
success = zip.WriteBd(binData) ' Long (1/0)
Introduced in version 9.5.0.66

Writes the ZIP archive to a BinData object instead of a filesystem file.

The generated ZIP archive exists entirely in memory.

The ZIP data written by this method may later be opened using OpenBd.

Returns 1 for success, 0 for failure.

More Information and Examples
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WriteExe
success = zip.WriteExe(exeFilename) ' Long (1/0)

(Windows only, for creating self-extracting EXE's)

Creates a Windows self-extracting executable (EXE).

The generated EXE contains both the extraction logic and the ZIP archive data.

There are no limitations on:

  • Total ZIP size
  • Individual file size
  • Number of files

The generated EXE supports the following command-line arguments:

  • -log logFileName
  • -unzipDir unzipDirectoryPath
  • -pwd password
  • -ap autoRunParams

Returns 1 for success, 0 for failure.

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WriteExeToMemory
bytes = zip.WriteExeToMemory() ' Variant

(Relevant only when running on a Microsoft Windows operating system.) Same as WriteExe, but instead of writing a file, the MS-Windows EXE is written to memory.

Returns a zero-length byte array (as a Variant) on failure.
An empty array will have a UBound of -1 meaning 0 elements.

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WriteToMemory
bytes = zip.WriteToMemory() ' Variant

Same as WriteZip, but instead of writing the Zip to a file, it writes to memory. Zips that are written to memory can also be opened from memory by calling OpenFromMemory.

Returns a zero-length byte array (as a Variant) on failure.
An empty array will have a UBound of -1 meaning 0 elements.

More Information and Examples
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WriteZip
success = zip.WriteZip() ' Long (1/0)

Saves the Zip to a file and implictly re-opens it so further operations can continue. Use WriteZipAndClose to write and close the Zip. There is no limitation on the size of files that may be contained within a .zip, the total number of files in a .zip, or the total size of a .zip. If necessary, WriteZip will use the ZIP64 file format extensions when 4GB or file count limitations of the old zip file format are exceeded.

Returns 1 for success, 0 for failure.

More Information and Examples
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WriteZipAndClose
success = zip.WriteZipAndClose() ' Long (1/0)

Saves the Zip to a file and closes it. On return, the Zip object will be in the state as if NewZip had been called. There is no limitation on the size of files that may be contained within a .zip, the total number of files in a .zip, or the total size of a .zip. If necessary, WriteZip will use the ZIP64 file format extensions when 4GB or file count limitations of the old zip file format are exceeded.

Returns 1 for success, 0 for failure.

More Information and Examples
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Deprecated

AppendBd
set zipEntry = zip.AppendBd(pathInZip, byteData) ' ChilkatZipEntry
Introduced in version 9.5.0.70
This method is deprecated and replaced by AddBd

This method is deprecated. Applications should instead call AddBd.

Appends the contents of byteData as a new entry to this zip object. The zip entry object containing the data is returned.

Returns Nothing on failure

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AppendData
set zipEntry = zip.AppendData(fileName, inData) ' ChilkatZipEntry
This method is deprecated and replaced by AddData

This method is deprecated. Applications should instead call AddData.

Appends in-memory data as a new entry to a Zip object. The ZipEntry object containing the data is returned.

Note: This method only updates the zip object. To update (rewrite) a zip file, either the WriteZip or WriteZipAndClose method would need to be called.

Returns Nothing on failure

More Information and Examples
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AppendDataEncoded
set zipEntry = zip.AppendDataEncoded(filename, encoding, data) ' ChilkatZipEntry
Introduced in version 9.5.0.59
This method is deprecated and replaced by AddEncoded

This method is deprecated. Applications should instead call AddEncoded.

Appends in-memory data as a new entry to a Zip object. The filename is the filename of the entry as it will appear within the zip. The encoding is the encoding of the data, such as base64, hex, etc. The full list of encodings is listed at the web page linked below.

Returns the zip entry object.

Note: This method only updates the zip object. To update (rewrite) a zip file, either the WriteZip or WriteZipAndClose method would need to be called.

Returns Nothing on failure

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AppendNew
set zipEntry = zip.AppendNew(fileName) ' ChilkatZipEntry
This method is deprecated and replaced by AddEmpty

This method is deprecated. Applications should instead call AddEmpty.

Appends a new and empty entry to the Zip object and returns the ZipEntry object. Data can be appended to the entry by calling ZipEntry.AppendData.

Important: To append an already-existing file, call the AppendOneFileOrDir method. The AppendNew method inserts a new and empty file entry within the Zip object. The purpose of AppendNew is to either create an empty file within the Zip, or to create a new file entry which can then be filled with data by calling the entry's AppendData method.

Note: This method only updates the zip object. To update (rewrite) a zip file, either the WriteZip or WriteZipAndClose method would need to be called.

Returns Nothing on failure

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AppendNewDir
set zipEntry = zip.AppendNewDir(dirName) ' ChilkatZipEntry
This method is deprecated and replaced by AddEmpty

This method is deprecated. Applications should instead call AddEmpty.

Adds an entry to the zip so that when it unzips, a new directory (with no files) is created. The directory does not need to exist on the local filesystem when calling this method. The dirName is simply a string that is used as the directory path for the entry added to the zip. The zip entry object is returned.

Note: This method only updates the zip object. To update (rewrite) a zip file, either the WriteZip or WriteZipAndClose method would need to be called.

Returns Nothing on failure

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AppendOneFileOrDir
success = zip.AppendOneFileOrDir(fileOrDirPath, saveExtraPath) ' Long (1/0)
This method is deprecated and replaced by AddFile

This method is deprecated. Applications should instead call AddFile.

Adds a file or directory to the object. If fileOrDirPath is an absolute file path and saveExtraPath is true, fileOrDirPath is converted to a relative file path for the zip entry. Otherwise, only the filename is stored. If fileOrDirPath is a relative file path, it is stored as-is in the zip, regardless of saveExtraPath.

Returns 1 for success, 0 for failure.

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AppendSb
success = zip.AppendSb(pathInZip, sb, charset) ' Long (1/0)
Introduced in version 10.0.0
This method is deprecated and replaced by AddSb

This method is deprecated. Applications should instead call AddSb.

Same as AppendString, but append the contents of of the sb, and allow the charset to be specified. The contents of sb is converted to charset before being added to the zip. The pathInZip is the path of the file that will be stored within the zip.

Note: This method only updates the zip object. To update (rewrite) a zip file, either the WriteZip or WriteZipAndClose method would need to be called.

Returns 1 for success, 0 for failure.

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AppendString
set zipEntry = zip.AppendString(internalZipFilepath, textData) ' ChilkatZipEntry
This method is deprecated and replaced by AddString

This method is deprecated. Applications should instead call AddString.

Adds an in-memory string to the Zip object. The textData argument is converted to the ANSI charset before being added to the Zip. If the Zip were written to disk by calling WriteZip, and later unzipped, the entry would unzip to an ANSI text file.

Note: This method only updates the zip object. To update (rewrite) a zip file, either the WriteZip or WriteZipAndClose method would need to be called.

Returns Nothing on failure

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AppendString2
set zipEntry = zip.AppendString2(internalZipFilepath, textData, charset) ' ChilkatZipEntry
This method is deprecated and replaced by AddString

This method is deprecated. Applications should instead call AddString.

Same as AppendString, but allows the charset to be specified. The textData is converted to charset before being added to the zip. The internalZipFilepath is the path of the file that will be stored within the zip.

Note: This method only updates the zip object. To update (rewrite) a zip file, either the WriteZip or WriteZipAndClose method would need to be called.

Returns Nothing on failure

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FirstEntry
set zipEntry = zip.FirstEntry() ' ChilkatZipEntry
This method is deprecated and replaced by EntryAt

This method is deprecated. Applications should instead call EntryAt.

Return the first entry in the Zip. Call ZipEntry.NextEntry to iterate over the entries in a Zip until a NULL is returned.

Returns Nothing on failure

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FirstMatchingEntry
set zipEntry = zip.FirstMatchingEntry(pattern) ' ChilkatZipEntry
This method is deprecated and replaced by EntryMatching

This method is deprecated. Applications should instead call EntryMatching.

Returns the first entry having a filename matching a pattern. The * characters matches 0 or more of any character. The full filename, including path, is used when matching against the pattern. A NULL is returned if nothing matches.

Returns Nothing on failure

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GetEntryByID
set zipEntry = zip.GetEntryByID(entryID) ' ChilkatZipEntry
This method is deprecated and replaced by EntryById

This method is deprecated. Applications should instead call EntryById.

Finds and returns the entry with the given entryID. (Each entry within the zip object has a unique EntryID.)

Returns Nothing on failure

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GetEntryByIndex
set zipEntry = zip.GetEntryByIndex(index) ' ChilkatZipEntry
This method is deprecated and replaced by EntryAt

This method is deprecated. Applications should instead call EntryAt.

Retrieves a ZipEntry by index. The first entry is at index 0. This will return directory entries as well as files.

Returns Nothing on failure

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GetEntryByName
set zipEntry = zip.GetEntryByName(entryName) ' ChilkatZipEntry
This method is deprecated and replaced by EntryOf

This method is deprecated. Applications should instead call EntryOf.

Returns the entry where the file path stored within the zip equals entryName.

Returns Nothing on failure

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GetExclusions
set stringArray = zip.GetExclusions() ' CkStringArray
This method is deprecated.

This method is deprecated and will removed in a future version of Chilkat.

Returns the current collection of exclusion patterns that have been set by SetExclusions.

Returns Nothing on failure

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SetPassword
zip.SetPassword password
This method is deprecated.

Sets both the decrypt password and encrypt password.

This method affects:

  • DecryptPassword
  • EncryptPassword

Note: This method is deprecated in favor of setting DecryptPassword and EncryptPassword separately.

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