.Net Components And Types

1. .Net Components And Types Bassem Elkarablieh

2. Outline • Modules • Assemblies • Object Model • Types • Runtime Type Information • Programming with Types

3. .net Code Journey

4. CLR Architecture

5. Modules • CLR programs reside into Modules • Modules contain: • Code(IL code) • MetaData ( module description) • Resources (any external resource) • Modules are not deployable components

6. Assemblies • Modules are the physical construct of the program that resides in file system • Assembly is a logical construct that interfaces with the CLR to access modules • Assemblies are references by a logical name • The CLR have a mechanism to identify assemblies

7. Assemblies continued • Assemblies are deployable modules • Each assembly has a manifest • Assemblies might have multiple modules • Only one manifest exists • Manifests describe the modules in the assembly • Assembly can be: • Executable application • Library

8. Assemblies

9. Compiling process • csc /t:module Speaker1.cs • csc /t:module Speaker2.cs • csc /t:library /addmodule:Speaker1.netmodule /addmodule:Speaker2.netmodule Speakers.cs • csc /t:exe /r:Speakers.dll Executive.cs

10. Manifests • Manifests contain: • Filenames of the internal modules • Type declaration of internal modules • Name of the assembly • MetaData Contain • List of all external dependencies • Type declarations of the assembly

11. Assembly names • Assembly names are four parts: • Logical friendly name • Version number • Culture • Public Key Token • Friendly names: simple name to reference the assembly • Culture: “en-us”,”ar-lb” Satellite

12. Versioning • Version number have the following structure: • Major.Minor.Build.Revision

13. Public Keys • Public keys resolves name confusions of assemblies • Public keys signs the module with the developer identity • Private keys can be used to digitally sign the assembly • Public key file can be generated using the sn.exe tool

14. Loading assemblies • If assembly is partially specified it can be loaded by friendly name • If assembly is fully specified , then the name should be resolved before the assembly is loaded

15. Loading Assemblies

16. .net Types • Every class declared in .net is a type • Types can include: • Fields • Methods • Properties • Events

17. CLR Type System

18. C++ Object Model

19. .net Runtime Object Model

20. Runtime type information object

21. How to call a method • If the method is a member of the type , then 3 pointer references are used • If the method is a base-member then more references are used depending on the length of the hierarchy

22. Type Casting • One of the main properties of .net is type safety. • Disadvantage of type checking is performance. • Three types of castings are possible: • Upcast • Downcast • Sidecast

23. Type Casting • Casting is the process of a linear search and match of the handles in the interface table and the Class hierarchy. • To support casting two opcodes are used( invisible from user) • Isinsit (is keyword) • Castclass(as Keyword) • Both opcode take the object and the desired type metadata pointer as arguments.

24. Type checking • The System.Type class is a façade to the internal Type structure. • Provides methods to check type compatibility • IsCompatible, Issubclassof • To get the type handle of any object use the inherited object.getType()

25. Programming With Types

26. System.Reflection • This namespace provide the Assembly object used in loading assemblies • The assembly object allows the accessing of the typemetadata. • Given the metadata we can get the type handle references. • Given the type Handel we can get member info.

27. System.Type • Assembly Asm = Assembly.Loadfrom(“x.dll”); • Type[] types = Asm.GetTypes(); • Foreach(Type t in types) • T.GetMembers() • T.GetMethods() • T.GetFields() • T.GetEvents()

28. Filtering Type selection • Using bindingflags • BindingFlags f = static|Instance|public|nonpublic|FlattenHirarchy • T.GetMembers(f); • We can also filter by name and the member type

29. End of Presentation