Shell Extensions for .NET Assemblies

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About the Shell Extensions for .NET Assemblies

These shell extensions were written to help distinguish between .NET assemblies and Win32 libraries, as well as give extra information about the assemblies without having to drop to a command-prompt to use the SDK and CLR tools. These shell extensions function similar to the loader that makes both .NET and VB (pre-.NET) possible as executable code: the PE/COFF header. As such, the library is very fast and won't hinder your file system browsing experience. A recent update further enhances performance by skipping assembly detection on slow paths, such as UNC paths or drive mappings to remote filesystems via VPN.

Provided in this library are:

1. Overlay icons for .NET assemblies (.dll)
   
    
   
   
2. Column handlers to show the public key token and specific type of .NET assemblies.
   
    
   
   
3. Automation object for getting the above information in your own applications and libraries.

The Automation Object

Not only does this tool help you distinguish between .NET assemblies and Win32 applications and libraries, but it also provides you with a simple automation object that these shell extensions use.

To generate code from the type library, add a reference or #import the type library named "AsmShell 1.0 Type Library". Use the members of the IAssemblyInfo automation interface as follows:

• IAssemblyInfo::IsAssembly([in]BSTR path, [out, retval]VARIANT_BOOL* retVal)
  Returns true if the specified file is an assembly, false if it is not, and raises errors when problems occur.
• IAssemblyInfo::GetFileType([in]BSTR path, [out, retval]FileType* retVal)
  Returns a FileType enumeration member depending on the information for the specified file in the PE/COFF header.
• IAssemblyInfo::GetPublicKeyToken([in]BSTR path, [out, retval]BSTR* retVal)
  Returns the public key token for the specified assembly.
• IAssemblyInfo::GetPublicKey([in]BSTR path, [out, retval]SAFEARRAY(BYTE)* retVal)
  Returns the public key as a byte array for the specified assembly. This is not supported by JScript or VBScript, both of which only support an array of VARIANTs.

For each method, late-binding languages like Visual Basic will use the return value (marked with [out, retval]) as the return type of the method, also getting rid of the need for the parameter labeled with the specified attributes above.

So, in VB6 and .NET (C#, VB.NET, et. al.), the methods signatures would look like:

bool IsAssembly(string path);
FileType GetFileType(string path);
string GetPublicKeyToken(string path);
byte[] GetPublicKey(string path);

Requirements

You may be required to reboot if files being installed are currently loaded. If you have Windows XP and the previous condition is false, no reboot should be necessary. If you're using Windows 98, ME, or 2000, you should either log off and back on or reboot your system if the overlay icon is not present; the column handlers should be ready immediately after the installation is finished.

Changes

• November 17, 2005
  • Note: late article update for an earlier release
  • Added support to display x86 (and MSIL) for assemblies, as well as IA64 and x64
• May 30, 2005
  • Added support for Windows Me
  • Added GetPublicKey method
  • Fixed crashing bug when sorting public key token column in Windows Explorer
  • Performance enhancements
  • See http://blogs.msdn.com/heaths/archive/2005/05/30/423293.aspx for more information.
• August 29, 2004
  • Added localizability
  • String caching for better performance
  • Support for .NET modules (.netmodule)
• October 15, 2003
  • Added condition that files should not be parsed for slow paths (ex: VPN)
• September 19, 2002
  • Initial release to the web on The Code Project

Disclaimer

THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR HIS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

This article, along with any associated source code and files, is licensed under The Microsoft Public License (Ms-PL)