Chapter 1 introduction to .net

CHAPTER 1 : INTRODUCTION TO .NET 2 Marks: 1. Write the use of common language specification(CLS) in .net architecture. Ans :- The basic use of CLS is to identify whether a particular language is .NET compliant language or not. Microsoft has released a small set of specifications that each language must satisfy so as to be used with .NET framework. These are set of standards or rules led down for languages to work under .NET umbrella. For example:- there should not be any global function declaration or there should not be multiple inheritance. If a language code is within these boundaries then it is said to be .NET compatible. 2. What are the uses of .net framework class library (FCL)? Ans :- Framework class library is also knownas base class library. Its main motive is to provide the common functions like String manipulations, Common data structures, IO, streams, Security, Threads, Windows programming, Network programming, Data access. The library follows extremely efficient Object Oriented design pattern which makes it more useful and easy to access. 3. List the basic building blocks used in .NET framework along with their use. Ans:- Namespaces: Namespaces are similar to packages in JAVA. It is a logical grouping of functionally related classes and helps in avoiding the errors occurring due to referring to the classes with same name. Namespace is a container (e.g Class, Structures, Interfaces, Enumerations, Delegates etc.), example System.IO logically groups input output related features, System.Data.SqlClient is the logical group of ADO.NET Connectivity with Sql server related features. System - This is a namespace is the root namespace for built in types provided by the Microsoft .NET framework and Object is the root class in the inheritance hierarchy of the System namespace. For example:- System.IO, System.threading, System.Drawing Assemblies: Assemblies are the building blocks of .NET framework, they form the fundamental unit of deployment, version control, reuse, scoping and security. It

contains the code that a CLR executes. It is the smallest unit of deployment of a .net application and it can be a .dll or an exe file. During the compile time Metadata is created with Microsoft Intermediate Language (MSIL) and stored in a file called Assembly Manifest. Both Metadata and Microsoft Intermediate Language (MSIL) together wrapped in a Portable Executable (PE) file. Every Assembly you create contains one or more program files and a Manifest. Assembly Manifest contains information about itself. It contains information about the members, types, references and all the other data that the runtime needs for execution. There are two types of program files: Process Assemblies (EXE) and Library Assemblies (DLL). Each Assembly can have only one entry point (that is, DllMain, WinMain, or Main). We can create two types of Assembly: 1. Private Assembly 2. Shared Assembly 4. Write the hardware and software requirements of .NET framework. Ans: Software requirements Windows XP service Pack 2 or Above, Windows server 2003 Service pack 1 or above, Windows server 2003 R2 or above, Windows Vista, Windows Server 2008, Windows 7, Windows 8, Windows 8.1, Windows 10 Hardware Requirements Hardware Minimum Recommended CPU 1.6 GHz 2.2 GHz or Higher RAM 384 MB 1024 MB or more Display 1024 x 768 1280 x 1024 Hard Disk 5400 RPM 7200 RPM or higher 5. Name any five .NET compatible languages. Ans:- VC++, VB.NET, Jscript.NET, J#, C#. 6. Write the use of ADO.NET component in .NET framework. Ans:- ADO.NET component of .NET framework is used for database connectivity for .NET application. ADO.NET consists of a set of Objects that expose data access services to the .NET environment. It is a data access technology from Microsoft .Net Framework, which provides communication between relational and non relational systems through a common set of components.

System.Data namespace is the core of ADO.NET and it contains classes used by all data providers. 7. Enlist the different .NET initiatives. Ans:- .NET Framework Version CLR Version Features Included in Visual Studio 1.0 1.0 First version of .NET framework Visual Studio .NET 1.1 1.1 ASP.NET and ADO.NET updates Side-by-side execution 2003 2.0 2.0 Generics ASP.NET additions 2005 3.0 2.0 WPF, WCF, WF, CardSpace - 3.5 2.0 AJAX-enabled websites LINQ, Dynamic data 2008 4 4 Expanded base class libraries Cross-platform 2010

development with Portable Class Library MEF, DLR, code contracts 4.5 4 Support for Windows Store apps WPF, WCF, WF, ASP.NET updates 2012 4.5.1 4 Support for Windows Phone Store apps Automatic binding redirection Performance and debugging improvements 2013 8. Enlist the different types of applications that can be developed using .NET. Ans:- ASP.NET web applications, Windows form based application, Console application, component libraries, windows custom controls, web custom control, web services, windows services

4 Marks: 1. Write the functions of CLR in brief. Ans:- CLR (Common Language Runtime) is a heart of Dot Net Framework. It works as a layer between Operating Systems and the applications written in .Net languages that conforms to the Common Language Specification (CLS). The main function of Common Language Runtime (CLR) is to convert the Programming language Code (Managed code) into native code and then execute the Program. The Managed Code compiled only when it needed, that is it converts the appropriate instructions when each function is called . The Common Language Runtime (CLR) 's Just In Time (JIT) compilation converts Intermediate Language (MSIL) to native code on demand at application run time. Common Language Runtime (CLR) manages Thread executions, Memory Management that is allocation of Objects and Buffers , Garbage Collection (GC) - Clean up the unused Objects and buffers , Exception Handling, Common Type System (CTS) that is all .NET language that conforms to the Common Language Specification (CLS) have the same primitive Data Types, Code safety verifications - code can be verified to ensure type safety, Language integration that is Common Language Runtime (CLR) follow a set of specification called Common Language Specification (CLS) , this will ensure the interoperability between languages, Integrated security and other system services. 1. Choosing the Source Code language compiler. At this stage we can choose the source code language for .NET. The primary languages available are C#, VB.NET and Python.

2. Compiling the source code to MSIL assemblies using the language compiler. Compiling the source code using the language compiler generates the corresponding assembly containing the MSIL. The assembly can be either a .exe or a .dll depending on the entry point defined in the Application. 3. Executing the code by CLR At execution time the CLR converts the MSIL to native code using the JIT compiler at runtime. JIT Compiler The CLR provides a JIT compiler for each supported CPU architecture. JIT converts the MSIL to native code at application execution time. Instead of converting all the code in the assembly to native code, the JITconverts the MSIL to native code as needed during execution and stores the resulting native code in memory, so the next time the same code is executed it will be executed directly from memory instead of being compiled again. The resulting MSIL will run on every CPU for which JIT compiler exists (and it exists for most CPU's), but if the managed code calls platform specific API's then it will not run on other platforms. When the method is loaded the loader attaches a stub to each method. Once the native code is generated for the method, the stub is modified to point to the native code, so the next time the method is called the native code is executed directly. Garbage Collector Garbage Collector handles automatic memory management and it will release memory of unused objects in an application, this provides automatic memory management. Security Engine It enforces security permissions at code level security, folder level security, and machine level security using Dot Net Framework setting and tools provided by Dot Net. 2. Explain the CTS and its use in detail. Ans: CTS (Common Type System): It specifies data types which are created in two different languages get compiled in to base common data type system. Common Type System (CTS) describes a set of types that can be used in different .Net languages in common. That is, the Common Type System (CTS) ensure that objects written in different .Net languages can interact with

each other. For Communicating between programs written in any .NET complaint language, the types have to be compatible on the basic level. These types can be Value Types or Reference Types . The Value Types are passed by values and stored in the stack. The Reference Types are passed by references and stored in the heap. Common Type System (CTS) provides base set of Data Types which is responsible for cross language integration. The Common Language Runtime (CLR) can load and execute the source code written in any .Net language, only if the type is described in the Common Type System (CTS). Most of the members defined by types in the .NET Framework Class Library (FCL) are Common Language Specification(CLS) compliant Types. 3. Write any eight points of difference between VB and VB.NET. Ans: Feature VB VB.NET Runtime Environment VB-runtime Common Language Runtime (CLR) Type Safety Not a type safe language Type safe language Exception handling ‘On Error GoTo’ syntax to handle exceptions at runtime Try-Catch-Finally block Threading No Multithreaded applications Can create multithreaded applications Types of Applications developed Desktop Windows applications Web applications, distributed applications Component Architecture Uses COM as a component Architecture Uses assemblies as its component architecture Database connectivity Uses ADODB and record sets to implement data access Uses ADO.NET and Datasets to built data access applications. Language Type Interpreter Based Compiler Based OOP Support Object Oriented programming is missing from VB Present in VB.NET Mathematical Poor in complex Fast in Complex

Calculations speed Mathematical Calculations Mathematical Calculations 4. Draw and explain the different types of application architectures. Ans:- Single Tier Architecture In single tier architecture database, application and presentation services i.e. the user interface all reside in the single system. These types of systems does no external processing apart from the platform on which it is running. 2-tier architecture In 2-tier, the application logic is either buried inside the User Interface on the client or within the database on the server (or both). With two tier client/server architectures, the user system interface is usually located in the user's desktop environment and the database management services are usually in a server that is a more powerful machine that services many clients. Processing management is split between the user system interface environment and the database management server environment. These applications are suited for small applications that do not have a lot of forms.

3-tier architecture In 3-tier, the application logic (or) process lives in the middle-tier, it is separated from the data and the user interface. Three tier architecture uses an XML web service to seperate the database access to another component which returns data to front end. 3-tier systems are more scalable, robust and flexible. Inaddition, they can integrate data from multiple sources. In the three tier architecture, a middle tier was added between the user system interface client environment and the database management server environment. There are a variety of ways of implementing this middle tier, such as transaction processing monitors, message servers, or application servers. The middle tier can perform queuing, application execution, and database staging. For example, if the middle tier provides queuing, the client can deliver its request to the middle layer and disengage because the middle tier will access the data and return the answer to the client. In addition the middle layer adds scheduling and prioritization for work in progress. Flexibility in partitioning can be a simple as "dragging and dropping" application code modules onto different computers in some three tier architectures. A limitation with three tier architectures is that the development environment is reportedly more difficult to use than the visually-oriented development of two tier applications. The most basic type of three tier architecture has a middle layer consisting of Transaction Processing (TP) monitor technology. The TP monitor technology is a type of message queuing, transaction scheduling, and prioritization service where the client connects to the TP monitor (middle tier) instead of the database server. The transaction is accepted by the monitor, which queues it and then takes responsibility for managing it to completion, thus freeing up the client.

Logical N-Tier Application Architecture The best approach to building an application using .NET is to separate all logical processes into discrete classes. In a typical application, this generally involves a business rule component, a data layer component, and the front-end code that uses these components. Using a logical N-tier development strategy is appropriate for all types of applications. It works equally well in small, medium and large applications with both desktop and web applications. 5. Explain the features of .NET. Ans: Interoperability Because interaction between new and older applications is commonly required, the .NET Framework provides means to access functionality that is implemented in programs that execute outside the .NET environment. Access to COM components is provided in the System.Runtime.InteropServices and System.EnterpriseServices namespaces of the framework; access to other functionality is provided using the P/Invoke feature. Common Runtime Engine The Common Language Runtime (CLR) is the virtual machine component of the .NET framework. All .NET programs execute under the supervision of the CLR, guaranteeing certain properties and behaviors in the areas of memory management, security, and exception handling. Language Independence

The .NET Framework introduces a Common Type System, or CTS. The CTS specification defines all possible datatypes and programming constructs supported by the CLR and how they may or may not interact with each other. Because of this feature, the .NET Framework supports the exchange of instances of types between programs written in any of the .NET languages. Base Class Library The Base Class Library (BCL), part of the Framework Class Library (FCL), is a library of functionality available to all languages using the .NET Framework. The BCL provides classes which encapsulate a number of common functions, including file reading and writing, graphic rendering, database interaction and XML document manipulation. Simplified Deployment The .NET framework includes design features and tools that help manage the installation of computer software to ensure that it does not interfere with previously installed software, and that it conforms to security requirements. Security The design is meant to address some of the vulnerabilities, such as buffer overflows, that have been exploited by malicious software. Additionally, .NET provides a common security model for all applications. Portability The design of the .NET Framework allows it to theoretically be platform agnostic, and thus cross-platform compatible. That is, a program written to use the framework should run without change on any type of system for which the framework is implemented. Microsoft submits the specifications for the Common Language Infrastructure (which includes the core class libraries, Common Type System, and the CommonIntermediate Language) making them available as open standards. This makes it possible for third parties to create compatible implementations of the framework and its languages on other platforms. 6. Explain the advantages of .NET framework. Ans: Managed Code Managed code is simply code written to execute in the .NET environment. Managed code offers a few benefits in terms of integrated security, type-safe code, and automatic memory allocation and deallocation.

Cross-Language Operation A .NET-compliant language is one that adheres to the Common Language Specification (CLS) and the Common Type System (CTS) laid out in the CLI. It is now possible to have C#, managed C++, and VB.NET code in the same module. Consistent programming model With .NET, accessing data with a C# and VB.NET very similar apart from slight syntactical differences. Both the programs need to import the System.Data namespace, both programs establish connection with database and both programs run a query and display the data. Direct Support for Security .Net framework enables the developer and the system administrator to specify method level security. Consider an application that accesses data on a remote machine or has to perform a privileged task on behalf of a non-privileged user.In this scenario security is much more important as application is accessing data from remote machine. With.NET the framework enables the developers and system administrator to specify method level security. Simplified Development efforts The .Net Framework simplifies debugging with support for three types of Runtime diagnostics Event logging, Performance counters and tracing. Runtime diagnostics helps you to track down bugs and also helps you to determine how well an application performs. Easy application deployment and Maintenance The .Net Framework makes easy to deploy applicaitons.The .Net Framework handles the details of locating and loads the components. Assemblies Assembly is elementary unit in a framework application. It performs various functions in programming with the .Net Frame work. Every computer that has the .Net Framework installed with have the Global Assembly Cache. 7. Explain any four drawbacks of previous languages. Ans: 1. It is not suited for modern programming techniques. Because it has been largely superseded by VB.NET and other languages. 2. Programs written in VBare not tend to be quickest as it requires additional code to be written which is not often necessary for program to run.

3. VB is interpreter based language which again slows the working of a program. 4. VB programs requires large libraries to work if you are not a programmer you have to download them. 5. OOP is missing from VB which is used by all new languages for code reuse. 6. There is no threading support in VB although it is available in VB.NET. 7. VB is good for windows applications but it is poor in web applications. 8. Draw architecture of .NET framework and also explain every component in detail. Also state the use of console, windows forms, asp.net and .net remoting. Ans: Common Language Infrastructure (CLI) The core aspects of the .NET Framework lie within the Common Language Infrastructure, or CLI. The purpose of the CLI is to provide a language-neutral platform for application development and execution, including functions for exception handling, garbage collection, security, and interoperability. Microsoft's implementation of the CLI is called the Common Language Runtime or CLR. Assemblies The CLI code is housed in .NET assemblies. As mandated by specification, assemblies are stored in the Portable Executable (PE) format, common on the Windows platform for all DLL and EXE files. The assembly consists of one or more files, one of which must contain the manifest, which has the metadata for the assembly. The complete name of an assembly contains its simple text name, version number, culture, and public key token. The public key token is a unique hash generated when the assembly is compiled, thus two assemblies with the same public key token are guaranteed to be identical from the point of view of the framework. A private key can also be specified known only to the creator of the assembly and can be used for strong naming and to guarantee that the assembly is from the same author when a new version of the assembly is compiled (required to add an assembly to the Global Assembly Cache). Metadata All assemblies are self-describing through .NET metadata. The CLR checks the metadata to ensure that the correct method is called. Metadata is usually generated by language compilers but developers can create their own metadata through custom attributes. Metadata contains information about the assembly, and is also used to implement the reflective programmingcapabilities of .NET Framework. Security

.NET has its own security mechanism with two general features: Code Access Security (CAS), and validation and verification. Code Access Security is based on evidence that is associated with a specific assembly. Typically the evidence is the source of the assembly (whether it is installed on the local machine or has been downloaded from the intranet or Internet). Code Access Security uses evidence to determine the permissions granted to the code. Other code can demand that calling code is granted a specified permission. The demand causes the CLR to perform a call stack walk: every assembly of each method in the call stack is checked for the required permission; if any assembly is not granted the permission a security exception is thrown. When an assembly is loaded the CLR performs various tests. Two such tests are validation and verification. During validation the CLR checks that the assembly contains valid metadata and CIL, and whether the internal tables are correct. Verification is not so exact. The verification mechanism checks to see if the code does anything that is 'unsafe'. The algorithm used is quite conservative; hence occasionally code that is 'safe' does not pass. Unsafe code will only be executed if the assembly has the 'skip verification' permission, which generally means code that is installed on the local machine. Base Class library (BCL) / Framework Class Library Namespaces in the BCL System System. CodeDom System. Collections System. Diagnostics System. Globalization System. IO System. Resources System. Text System. Text.RegularExpressions The .NET Framework includes a set of standard class libraries. The class library is organized in a hierarchy of namespaces. Most of the built in APIs are part of either System.* or Microsoft.* namespaces. These class libraries implement a large number of common functions, such as file reading and writing, graphic rendering,

database interaction, and XML document manipulation, among others. The .NET class libraries are available to all .NET languages. The .NET Framework class library is divided into two parts: the Base Class Library and the Framework Class Library. The Base Class Library (BCL) includes a small subset of the entire class library and is the core set of classes that serve as the basic API of theCommon Language Runtime. The classes in mscorlib.dll and some of the classes in System.dll and System.core.dll are considered to be a part of the BCL. The BCL classes are available in both.NETFramework as well as its alternative implementations including .NET Compact Framework,Microsoft Silverlight and Mono. The Framework Class Library (FCL) is a superset of the BCL classes and refers to the entire class library that ships with .NET Framework. It includes an expanded set of libraries, including WinForms, ADO.NET, ASP.NET,Language Integrated Query, Windows Presentation Foundation,Windows Communication Foundation among others. The FCL is much larger in scope than standard libraries for languages like C++, and comparable in scope to the standard libraries of Java. Memory management The .NET Framework CLR frees the developer from the burden of managing memory (allocating and freeing up when done); instead it does the memory management itself. To this end, the memory allocated to instantiations of .NET types (objects) is done contiguously from the managed heap, a pool of memory managed by the CLR. As long as there exists a reference to an object, which might be either a direct reference to an object or via agraph of objects, the object is considered to be in use by the CLR. When there is no reference to an object, and it cannot be reached or used, it becomes garbage. However, it still holds on to the memory allocated to it. .NET Framework includes a garbage collector which runs periodically, on a separate thread from the application's thread, that enumerates all the unusable objects and reclaims the memory allocated to them. The .NET Garbage Collector (GC) is a non-deterministic, compacting, mark-and-sweep garbage collector. The GC runs only when a certain amount of memory has been used or there is enoughpressure for memory onthe system. Since it is not guaranteed when the conditions to reclaim memory are reached, the GC runs are non-deterministic. Each .NET application has a set of roots, which are pointers to objects on the managed heap (managed objects). These include references to static objects and objects defined as local variables or method parameters currently in scope, as well as objects referred to by CPU registers When the GC runs, it pauses the application, and for each object referred to in the root, it recursively enumerates all the objects reachable from the root objects and marks them as reachable. It uses .NET metadata andreflection to discover the objects encapsulated by an object, and then recursively walk them. It then enumerates all the objects on the heap (which were initially allocated contiguously) using reflection. All objects not marked as reachable

are garbage. This is the mark phase. Since the memory held by garbage is not of any consequence, it is considered free space. However, this leaves chunks of free space between objects which were initially contiguous. The objects are then compacted together, by using memcpy to copy them over to the free space to make them contiguous again. Any reference to an object invalidated by moving the object is updated to reflect the new locationby the GC. The application is resumed after the garbage collection is over. The GC used by .NET Framework is actually generational. Objects are assigned a generation; newly created objects belong to Generation 0. The objects that survive a garbage collectionare tagged as Generation1, and the Generation 1 objects that survive another collection are Generation 2objects. The .NET Framework uses up to Generation 2 objects. Higher generation objects are garbage collected less frequently than lower generation objects. This helps increase the efficiency of garbage collection, as older objects tend to have a larger lifetime than newer objects. Thus, by removing older (and thus more likely to survive a collection) objects from the scope of a collection run, fewer objects need to be checked and compacted. Console Console applications refer to the traditional DOS kind of applications like batchscripts. Here the user is not provided with GUI based applications. Windows forms These are the traditional rich client applications including GUI. ASP.NET web applications These types of applications include dynamic data driven browser based applications. .NET Remoting .NET remoting enables you to build widely distributed applications easily, whether the application components are all on one computer or spread out across the entire world. You can build client applications that use objects in other processes on the same computer or on any other computer that is reachable over its network. You can also use .NET remoting to communicate with other application domains in the same process. .NET remoting provides an abstract approach to interprocess communication that separates the remotable object from a specific client or server application domain and from a specific mechanism of communication. You can replace one communication protocol with another, or one serialization format with another without recompiling the client or the server. In addition, the remoting system assumes no particular application model. You can communicate from a Web application, a console application, a Windows Service – from almost anything you want to use. Remoting servers can also be any type of

application domain. Any application can host remoting objects and provide its services to any client on its computer or network. To use .NET remoting to build an application in which two components communicate directly across an application domain boundary, you need to build only the following: 1. A remotable object. 2. A host application domain to listen for requests for that object. 3. A client application domain that makes requests for that object. Even in a complex, multiclient or multiserver application, .NET remoting can be thought of in this way. The host and the client application must also be configured with the remoting infrastructure and you must understand the lifetime and activation issues that the remoting infrastructure introduces.

Chapter 1 introduction to .net

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Chapter 1 introduction to .net