.Net Introduction

1. .Net Introduction Created by Neetu Gangwani

2. What is .Net? • .NET is a framework which allow us to build distributed, secure, scaleable, robust, easily deployable and maintainable applications in a language independent, object oriented, web enabled, managed way using rich level of integration amongst present technologies. Created by Neetu Gangwani

3. Windows application Word, excel Component library Scheduler.dll Chatmaster.dll Web application Any home page E-commerce site Distributed application Banking application E-commerce application Mobile apps Trip planner Pocket reminder Embedded apps Flight controller Engine controller Type of applications Created by Neetu Gangwani

4. Adv. Of .NET • Consistent programming model • Powerful class library • Language of choice • Better runtime • Language interoperability • Built on same OS. Created by Neetu Gangwani

5. Objectives of .Net Framework • To provide a consistent object-oriented programming environment whether object code is stored and executed locally, executed locally but Internet-distributed, or executed remotely. • To provide a code-execution environment that promotes safe execution of code, including code created by an unknown or semi-trusted third party. Created by Neetu Gangwani

6. Objectives of .Net Framework • To provide a code-execution environment that eliminates the performance problems of scripted or interpreted environments. • To make the developer experience consistent across widely varying types of applications, such as Windows-based applications and Web-based applications. • To build all communication on industry standards to ensure that code based on the .NET Framework can integrate with any other code. Created by Neetu Gangwani

7. .Net Framework • Consist of • Base Class Library • CTS (Common Type System) • CLS (Common Language Specification) • CLR (Common Language Runtime) Created by Neetu Gangwani

8. VB C# C++ JScript ……… Common Language Specification (CLS) ASP.NET Windows Forms ADO.NET XML Visual Studio .NET Base Class Library Common Language Runtime (CLR) Windows COM+ Services Created by Neetu Gangwani

9. Common programming model • The elegance of .NET is that if a form has been design in C#, one can either use it as it is or inherit that form to add some more functionality before displaying it. • Winform controls as compare to ActiveX controls can be easily developed and can be used in the different languages. Created by Neetu Gangwani

10. Base class library • The .NET framework includes a rich set of classes that provides the comprehensive functionality for any type of application one intends to develop. • The application’s functionalities like messaging, database access, security, drawing and many more. • All the classes in the framework class library are organized in different namespaces. Created by Neetu Gangwani

11. Common Type System • The common type system defines how types are declared, used, and managed in the runtime, and is also an important part of the runtime's support for cross-language integration. The common type system performs the following functions: • Establishes a framework that helps enable cross-language integration, type safety, and high performance code execution. • Provides an object-oriented model that supports the complete implementation of many programming languages. • Defines rules that languages must follow, which helps ensure that objects written in different languages can interact with each other. Created by Neetu Gangwani

12. CLS • To fully interact with other objects regardless of the language they were implemented in, objects must expose to callers only those features that are common to all the languages they must interoperate with. For this reason, the Common Language Specification (CLS), which is a set of basic language features needed by many applications, has been defined. The CLS rules define a subset of the Common Type System. that is, all the rules that apply to the common type system apply to the CLS, except where stricter rules are defined in the CLS. The CLS helps enhance and ensure language interoperability by defining a set of features that developers can rely on to be available in a wide variety of languages. Created by Neetu Gangwani

13. Common Language Runtime • CLR handles object creation and destruction and hence relieves programmer from destroying the object explicitly. • CLR releases the object when they are no longer being used. • Automatic memory management eliminates memory leaks as well as some other programming errors. • CLR also handles runtime errors and informs the concerned application about them. • CLR also provides a secured environment when a winform application is downloaded from the web server. • Cross-language integration, especially cross-language inheritance. • Garbage collection, which manages object lifetime so that reference counting is unnecessary. Created by Neetu Gangwani

14. Runtime • When .NET compliant language complier complies the source code it emits code in intermediate language (IL). • This code is processor independent code. • The Just-In-Time (JIT) complier that Common language runtime (CLR) provides complies this code to the processor specific code (native code) which is then executed • The advantage of the IL is that it can be executed wherever .NET is present. Created by Neetu Gangwani

15. MSIL • When compiling to managed code, the compiler translates your source code into Microsoft intermediate language (MSIL), which is a CPU-independent set of instructions that can be efficiently converted to native code • MSIL includes instructions for loading, storing, initializing, and calling methods on objects, as well as instructions for arithmetic and logical operations, control flow, direct memory access, exception handling, and other operations. Created by Neetu Gangwani

16. MSIL & Metadata • Before code can be run, MSIL must be converted to CPU-specific code, usually by a JIT (Just in time compiler). • When a compiler produces MSIL, it also produces metadata. Metadata describes the types in your code, including the definition of each type, the signatures of each type's members, the members that your code references, and other data that the runtime uses at execution time. Created by Neetu Gangwani

17. MetaData • Metadata is binary information describing your program that is stored either in a common language runtime portable executable (PE) file or in memory. When you compile your code into a PE file, metadata is inserted into one portion of the file, while your code is converted to Microsoft intermediate language (MSIL) and inserted into another portion of the file. Every type and member defined and referenced in a module or assembly is described within metadata. When code is executed, the runtime loads metadata into memory and references it to discover information about your code's classes, members, inheritance, and so on. Created by Neetu Gangwani

18. MetaData • Description of the assembly. • Identity (name, version, culture, public key). • The types that are exported. • Other assemblies that this assembly depends on. • Security permissions needed to run. • Description of types. • Name, visibility, base class, and interfaces implemented. • Members (methods, fields, properties, events, nested types). • Attributes. • Additional descriptive elements that modify types and members Created by Neetu Gangwani