C# 4 and .NET 4

434 ❘ ChaPTer 18 Assemblies
namespaces, assemblies, and Components
You might be a little bit confused by the meanings of namespaces, types, assemblies, and components. How
does a namespace fi t into the assembly concept The namespace is completely independent of an assembly.
You can have different namespaces in a single assembly, but the same namespace can be spread across
assemblies. The namespace is just an extension of the type name — it belongs to the name of the type.
For example, the assemblies mscorlib and system contain the namespace System.Threading among many
other namespaces. Although the assemblies contain the same namespaces, you will not find the same class names.
Private and shared assemblies
Assemblies can be shared or private. A private assembly is found either in the same directory as the
application, or within one of its subdirectories. With a private assembly, it ’ s not necessary to think about
naming confl icts with other classes or versioning problems. The assemblies that are referenced during
the build process are copied to the application directory. Private assemblies are the usual way to build
assemblies, especially when applications and components are built within the same company.
Although it is still possible to have naming confl icts with private assemblies (multiple
private assemblies may be part of the application and they could have confl icts, or a
name in a private assembly might confl ict with a name in a shared assembly used by the
application), naming confl icts are greatly reduced. If you fi nd you ’ ll be using multiple
private assemblies or working with shared assemblies in other applications, it ’ s a good
idea to utilize well - named namespaces and types to minimize naming confl icts.
When using shared assemblies, you have to be aware of some rules. The assembly must be unique and,
therefore, must also have a unique name, called a strong name. Part of the strong name is a mandatory
version number. Shared assemblies will mostly be used when a vendor, different from that of the application,
builds the component, or when a large application is split into subprojects. Also, some technologies, such as
.NET Enterprise Services, require shared assemblies in specifi c scenarios.
satellite assemblies
A satellite assembly is an assembly that only contains resources. This is extremely useful for localization.
Because an assembly has a culture associated, the resource manager looks for satellite assemblies containing
the resources of a specifi c culture.
You can read more about satellite assemblies in Chapter 22, “ Localization. ”
Viewing assemblies
You can view assemblies by using the command - line utility
ildasm , the MSIL disassembler. You can open an assembly by
starting ildasm from the command line with the assembly as
an argument or by selecting the File ➪ Open menu.
Figure 18 - 3 shows ildasm opening the example that you will
build a little later in the chapter, SharedDemo.dll . ildasm
shows the manifest and the SharedDemo type in the Wrox
.ProCSharp.Assemblies namespace. When you open the
manifest, you can see the version number and the assembly
attributes, as well as the referenced assemblies and their versions.
You can see the MSIL code by opening the methods of the class. figure 18-3
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