ASP.NET in a Nutshell

Sharing Controls Across Applications

The architecture of the .NET Framework makes using a custom server control or other assembly as simple as copying that assembly to the bin subdirectory of your application and adding the appropriate directives and tags to your page. However, there may be times when you would like multiple applications on the same machine to be able to use the same control, without having multiple local copies of the control’s assembly floating around.

Fortunately, .NET addresses this need with the Global Assembly Cache (GAC), a repository of shared assemblies that are accessible to all .NET applications on a given machine. Adding your own control assemblies to the GAC is a relatively straightforward process that requires four steps:

1. Use the sn.exe command-line utility to create a public key pair for use in signing your control:

   sn.exe -k Blog.snk

2. Add the AssemblyKeyFileAttribute to the file containing the control code, passing the path to the keyfile created in Step 1 as an argument. (This is an assembly-level attribute, so it should be placed outside of any namespace or class definitions.) When compiled, this attribute will result in a strongly named assembly that can be placed in the GAC:

   [assembly: AssemblyKeyFileAttribute("Blog.snk")]

3. Recompile the control.

4. Add the control to the GAC, either by dragging and dropping the assembly in Windows Explorer or by using the gacutil.exe utility, as follows:

   gacutil -i Blog.dll

   Tip

   Note that as with the csc.exe and vbc.exe ...