This article describes how to generate a strong name for an
assembly and to install a .dll file in the Global Assembly Cache. The Global
Assembly Cache (GAC) enables you to share assemblies across numerous
applications. The GAC is automatically installed with the .NET runtime.
Components are typically stored in C:\WINNT\Assembly.
In order to
install an assembly in the GAC, you must give the assembly a strong (that is,
globally unique) name. Actually, it is not a name but a cryptographic hash key,
or signature. The strong name ensures correct component versioning, which helps
to prevent components that have the same name from conflicting with each other
or being incorrectly used by a consuming application.
Requirements
The following items describe the recommended hardware, software,
network infrastructure, skills and knowledge, and service packs that you need:
- Administrator rights to the computer on which the shared
assembly is being installed
Prior knowledge required:
- General familiarity with assemblies in .NET
- General familiarity with the use of tools from the
command-line prompt
Global Assembly Cache
To create a small Class Library project by using Visual Studio
.NET or Visual Studio 2005, to generate a strong name, and to install the
project's .dll file in the Global Assembly Cache, follow these steps:
- Open Visual Studio .NET or Visual Studio 2005.
- Create a new Class Library project named
GAC in Visual Basic .NET or in Visual Basic
2005.
- A strong name is needed. To generate this cryptographic key
pair, use the SN Tool, which is located in the \bin subdirectory, where the
.NET Framework Solution Developer Kit (SDK) is installed. The SN Tool is very
easy to use. The command-line statement takes the following form:
sn -k "C:\[DirectoryToPlaceKey]\[KeyName].snk"
- For convenience, create a directory named
GACDemo in C:\ so that you can easily locate the key and
access the key from the command prompt.
NOTE: For most users, the .NET tools are located in C:\Program
Files\Microsoft.NET\FrameworkSDK\Bin. Before you type the following SN command,
you may want to copy this similar path on your computer to the .NET bin
directory, type cd from the command prompt, right-click
to paste the path, and then press ENTER to quickly change the directory where
the SN Tool is located.
Type the following: sn -k "C:\GACDemo\GACkey.snk"
Note In the .NET Framework 2.0, the .NET tools are located in the
C:\Program Files\Microsoft.NET\SDK\v2.0\Bin folder. - A key is generated, but it is not yet associated with the
project's assembly. To create this association, double-click the AssemblyInfo.vb file in the Visual Studio .NET or Visual Studio 2005 Solution
Explorer. Add the following to the list of assembly attributes that are
included in this file by default when a project is created in Visual Studio
.NET or in Visual Studio 2005:
<Assembly: AssemblyKeyFile("C:\GACDemo\GACKey.snk")>
Compile the project by clicking CTRL+SHIFT+B. No further code is
necessary at this point in order to install a .dll file in the GAC. - You can install the .dll file by using the Gacutil Tool or
by dragging the .dll file into the appropriate directory. If you use the
Gacutil Tool, you can use the following command:
gacutil -I "C:\[PathToBinDirectoryInVSProject]\gac.dll"
If you want to drag the file, use Microsoft Windows Explorer.
Open two instances of Windows Explorer. In one, navigate to the location of the
.dll file output for your console project. In the other, navigate to
c:\[SystemRoot]\Assembly.
Drag your .dll file into the
folder.
Complete Code Listing (AssemblyInfo.vb)
Imports System.Reflection
Imports System.Runtime.InteropServices
<Assembly: AssemblyTitle("")>
<Assembly: AssemblyDescription("")>
<Assembly: AssemblyCompany("")>
<Assembly: AssemblyProduct("")>
<Assembly: AssemblyCopyright("")>
<Assembly: AssemblyTrademark("")>
<Assembly: CLSCompliant(True)>
<Assembly: AssemblyKeyFile("C:\GACDemo\GACKey.snk")>
<Assembly: Guid("E3492A62-5389-4286-94A3-1331CC29EA6D")>
<Assembly: AssemblyVersion("1.0.*")>
Verification
- Start Windows Explorer.
- Navigate to C:\WINNT\assembly.
- Find GAC in the list of installed .dll files.
REFERENCES
For more information, visit the following Microsoft Web sites: