Intro to ASP.NET CS-422 Dick Steflik

What is.NET As applications in the Enterprise become more and more netcentric and less and less standalone.NET is Microsoft’s computing platform for the new millenia. It provides: –OS-Neutral Environment –Device Independence –Wide Language Support –Internet based Component Services

OS-Neutral Environment Underlying.NET runtime libraries make it possible to build both desktop and Web based applications without calling the OS code. –Eliminates need to have detailed understanding about the Windows OS By porting the runtimes to other non-Microsoft computing platforms.NET applications are easily used in other computing platforms –FreeBSD – in progress –Linux – in progress

Device Independence.NETs output has been targeted for use on a variety of devices including Web, Desktop and Mobile –Web Forms –Mobile Internet Tools (MIT) SDK Goal is to make a single source code library that will run on any device

Wide Language Support The.NET platform ships with support for three Microsoft Languages: –C# –Visual Basic –Jscript Additionally a version of C++ called Managed C++ that interfaces with the.NET runtimes for building agile desktop applications Much of.NET is written in C#

C# Object –oriented Type-safe Garbage collected Many similarities with Java –Virtual machine environment

Visual Basic Updated version of Visual Basic 6.0 –Full object-orientation –Not upwards compatible with VB 6.0 Porting from VB 6.0 to VB.NET is considered a non-trivial task

Jscript New version of the ECMA Jscript scripting language –Used in Internet Explorer and ASP –Fully compiled –Not upwards compatible with previous versions of Jscript requires minimal changes

Other Language Support Fujitsu – COBOL.NET ActiveState – PERL.NET Interactive Software Engineering – Eiffel for.NET

Internet-Based Component Services.NET allows any internet location to become a distributed component –Web Services –XML Simple Object Access Protocol (SOAP) Web Services Definition Language (WSDL)

Common Language Runtime (CLR) The.NET Virtual Machine –Parsing and execution of all.NET application instructions –Manages deployment and security –Class libraries System Classes Data and XML Classes Windows and Drawing Classes The Web Classes

CLR Internals CLR provides the following low level services: –Code Management – locating and executing code, thread management, stack and heap management –Security Support – evidence based security model for code access security, high-level user and group access security –Garbage Collection and Error Handling – optomized garbage collection for.NET, error management, stack tracing and debugging Base Class Library Support Thread Manager COM Marshalling Type Checking Exception Handling SecurityDebugging Native Compilers Code Manager CG Services Class Loader

Code Management and Execution Primary job is to convert CLR Intermediate Language to platform executable code –Similar idea to Java JIT Compilers Source CodeLanguage Compiler Intermediate LanguageJIT Native Code

Security Support Keeps track of security evidence items like permissions, code location (remote or local), user rights and privileges to enforce evidence based security policies Evidence Items Security Policies Security Policy Engine Resulting Permissions

Error handling and Garbage Collection Try/Catch based error handling Objects and memory variables are garbage collected when no longer needed –Highly deterministic algorithms –Always close any open resources before releasing objects