An assembly in .NET contains compiled code and metadata. It can be an EXE or DLL file. When code is compiled, it is translated to IL code and metadata is generated. The IL and metadata are bundled into the assembly file. Assemblies can be private, used by a single app, or shared, used by multiple apps. Shared assemblies are stored in the global assembly cache so they only need to be deployed once. The ILDASM tool allows examining the contents of an assembly.

1. Assemblies in .Net
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2. What is an Assembly
• When create a project in Visual Studio .Net and
compile it, assemblies are created.
- .DLL
- .EXE
• These assemblies are the fundamental units of
applications in the .NET Framework.
• An assembly contains one or more compiled classes.
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3. • When compile a program, the compiler translates
the source code into the Intermediate Language
code (IL).
• In addition to translating the code into IL, the
compiler also produces metadata about the program
during the process of the compilation.
• The IL and the metadata are linked in an assembly.
• An IL and metadata exist in portable executable
file(EXE/DLL).
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4. • In any Project folder, In bin folder that contains,
say myproject.dll/ myproject.exe and
myproject.pdb files.
• The myproject.dll/ myproject.exe is the assembly,
and myproject.pdb ( program database ) file
contains debugging information for the assembly.
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5. Structure of Assemblies
• An assembly also contains an assembly manifest that
contains the assembly metadata.
• This metadata contains information about the
classes, methods and properties and so on
• This information is stored within the assembly file
(DLL/EXE) itself.
• Resources are non executable data that is a part of
Application.
e.g: images, sound and video etc.
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6. Process assemblies (EXE) and library assemblies (DLL)
• A process assembly represents a process which uses
classes defined in library assemblies
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7. Feature of Assemblies
• Assemblies are self describing
• Assembly can be load side by side
• Assembly can be private or shared
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8. Why use Assemblies?
• The goal of the assembly model is the elimination of
DLL Hell. Under the current model.
• A catalog of DLLs is centralized in the Windows
Registry.
• When a new version of a DLL is published, the
registry re-references the catalog to point to the new
DLL.
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9. Types of Assemblies
• Assemblies can be private or shared.
• The assembly which is used by a single
application is called as private assembly.
• Suppose we have created a DLL which
encapsulates business logic. This DLL is used
by the client application only and not by any
other application.
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10. Shared assemblies
• Suppose we are creating a general purpose DLL
which provides functionality to be used by a variety
of applications. Now, instead of each client
application having its own copy of DLL we can place
the DLL in 'global assembly cache'. Such assemblies
are called as shared assemblies.
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11. Benefits of Private Assemblies
• Private assemblies are installed in a directory
named bin located under the application
directory. These files are private to the
application.
• It is great for small utility Assemblies/
application specific code
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12. Disadvantages:
• When you have multiple applications using
one assembly, you have to deploy the
assembly to the bin directory of each
application.
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13. How to create an Assembly
• A shared assembly can be created in Visual
Studio.Net by a Pair of tool.
- SN.exe utility.
- Gacutil tool
• The sn.exe utility is located in the Bin directory.
• After creating the shared assembly we should sign
the shared assembly to the GAC by using Gacutil
tool.
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14. Calculator.cs MathProgram.cs
using System;
namespace calculate
using calculate;
{
public class mathoperation class mycalc
{ {
public int subtraction(int a, int static void Main()
b) {
{ mathoperation c1 = new mathoperation();
return a-b; int result = c1.subtraction(50,20);
Console.WriteLine("The result is:{0}",result);
} Console.Read();
} }
}
}
c:>csc /t:library Calculator.cs
c:>csc /t: /r:Calculator.dll MathProgram.cs
Created DLL file “Calculator.dll” Created EXE file “MathProgram.exe”
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15. What is Global Assembly Cache?
• An assembly that is shared by multiple applications is
called a global assembly and is installed in the global
assembly cache (GAC).
• Global assembly cache is nothing but a special disk
folder where all the shared assemblies are kept.
• It is located under <drive>:WindowsAssembly
folder on every machine running the .NET
framework.
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16. Add an External Tool
• Visual Studio provides the functionality to
include external tools in the Tools menu.
• To modify the existing tools or to add new
tools of your own, you simply need to go to
Tools → External Tools.
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17. What is ILDASM ?
• It is Intermediate Language Dissembler SDK
Tool that is used to examine MSIL code and
the parts of the Assembly.
• It comes with the installation of Visual Studio
IDE.
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18. How to Add an External Tool
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19. Click on add button and spedify name ILDASM.
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21. View the content of an Assembly
Click on File menu and Then Open a File
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22. Select an Assembly File and Open
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23. Double Click on Manifest
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24. Double Click on mycalc
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25. • End of Presentation.
• Thank’s for Watching.
JANAS KHAN
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