Advanced Zip Library

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Advanced Zip Library

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About AZL

The "Advanced Zip Library" (or AZL for short) is a set of COM DLL's, VB Modules, VB Classes, VB.NET modules, and compiled .NET assemblies that when added to your project gives you the ability to open, inspect, modify, or create standard ZIP files (which are fully compatible with such popular ZIP tools as WinZip, PKZIP, WinRAR, and StuffIt. Because you are given direct access to all the modules and classes, you can compile everything right into your VB5, VB6, or VB.NET project. Or you can use the compiled libraries to enhance programs written in any "COM-aware" development environment (i.e. - VB5, VB6, VB.NET, VbScript, REALbasic, DELPHI, C++, VC++, C++.NET, C#.NET, Classic ASP, ASP.NET, JavaScript, JSP, Java, J#.NET, PHP, etc.).

  • The files "AdvZipLib.dll" and "AdvZipLib5.dll" are COM DLL's and need to be registered using REGSVR32.EXE (unless you put them in the same directory as your application). These should be in the same directory as your application, or in the Windows\System folder.

  • The "AdvZipLib_NET.dll" files are .NET assemblies and do not need to be registered. These should be in your project's \BIN\ directory, or in the Windows\System folder.

  • The files "ZIP32.DLL" and "UNZIP32.DLL" are static C-style DLL's and do not need to be registered. These should be in the same directory as your application, or in the Windows/System directory.

  • During testing, some functions would sometimes be fairly unstable within a .NET development environment. They would cause strange "object reference not set" errors, memory exceptions, or would simply hang Visual Studio .NET. This is most likely due to something in the underlying Info-ZIP libraries not "playing nice" with .NET... which isn't hard to imagine since the Info-ZIP libraries are unmanaged "C" code, and .NET tries to force everything into a managed code environment. However, the same functions work fine in VB5, VB6, ASP, or REALbasic development environments. Because of this, it is recommended that if you are developing a .NET application that you reference the VB6 version (AdvZipLib.dll) instead of the .NET version (AdvZipLib_NET.dll). Referencing and using a COM library from .NET works fine because .NET has built-in support for them via it's COM Interop functionality.

  • If you are developing using REALbasic, you will not be able to use one of the main functions within the AZL library, "Info_FileList" which lists all the files within a ZIP archive file. The reason for this is as of REALbasic 2007r3, there is no proper support for passing arrays of String, Date, and 16-bit Integer values to COM / OLE objects via the OLEParameter object. Click here for a list of bug reports that have been created for these issues, and information about their current status.

This software uses the Info-ZIP open source compression library.
See for details.
Info-ZIP is used under a BSD-like (i.e., very liberal) license

Click here to purchase the Advanced Zip Library.