© 2004 the University of Greenwich 1
Introduction to the Weband .NET
Kevin McManus
Adapted from material by Mark SapossnekComputer Science Department
Metropolitan CollegeBoston University
© 2004 the University of Greenwich 1
© 2004 the University of Greenwich 2
Agenda
• Internet Technologies
• Programming Languages and Paradigms
• Programming the Web
• .NET Overview
© 2004 the University of Greenwich 3
WWW Architecture
Platform: PC, Mac, Unix, etc.Web Server: Apache, IIS, Xitami, etc.
Platform: PC, Mac, Unix, etc.Browser: IE, Mozilla, Opera, etc.Client
Server
Request:http://www.gre.ac.uk/about
Response:<html>…</html>
Network HTTP over TCP/IP
© 2004 the University of Greenwich 4
Internet TechnologiesWWW Architecture
• Client/Server, Request/Response architecture• You request a Web page
• e.g. http://www.msn.com/default.asp?name-Leon• HTTP request
• The Web server responds with data in the form of a Web page• HTTP response• Web page is expressed as (X)HTML
• Pages are identified as a Uniform Resource Locator (URL)• Protocol: http• Web server: www• Domain msn.com• Web page: default.asp• GET parameters: ?name=Leon
© 2004 the University of Greenwich 5
Internet TechnologiesWeb Standards
• Internet Engineering Task Force (IETF)• http://www.ietf.org/
• Founded 1986
• Request For Comments (RFC) at http://www.ietf.org/rfc.html
• World Wide Web Consortium (W3C)• http://www.w3.org
• Founded 1994 by Tim Berners-Lee
• Publishes technical reports and recommendations
© 2004 the University of Greenwich 6
Internet TechnologiesHypertext Markup Language (HTML)
• The markup language used to create web pages for viewing by people• Designed to display data, not store/transfer data
• Rendered and viewed in a Web browser• Can contain links to images, documents,
and other pages• W3C standard• Derived from Standard Generalized Markup Language
(SGML)• HTML 3.2, 4.01, XHTML 1.0
© 2004 the University of Greenwich 7
Internet TechnologiesHTML Forms
• Enables you to create interactive user interface elements• Buttons• Text boxes• Lists, menues• Check boxes, radio buttons
• User fills out the form and submits it• Form data is sent to the web server when the
form is submitted• Part of the HTTP request• use either the GET or POST method
© 2004 the University of Greenwich 8
Internet TechnologiesHypertext Transport Protocol (HTTP)
• The top-level protocol used to request and return data • e.g. HTML pages, GIFs, JPEGs, Microsoft Word
documents, Adobe PDF documents, etc.
• Request/Response protocol• Methods: GET, POST, HEAD, …• HTTP 1.0: simple • HTTP 1.1: more complex
© 2004 the University of Greenwich 9
GET /default.asp HTTP/1.0Accept: image/gif, image/x-bitmap, image/jpeg, */*Accept-Language: enUser-Agent: Mozilla/1.22 (compatible; MSIE 2.0; Windows 95)Connection: Keep-AliveIf-Modified-Since: Sunday, 17-Apr-96 04:32:58 GMT
Internet TechnologiesHTTP Request
Method File HTTP version Headers
Data – none for GET
Blank line
© 2004 the University of Greenwich 10
HTTP/1.0 200 OKDate: Sun, 21 Apr 1996 02:20:42 GMTServer: Microsoft-Internet-Information-Server/5.0 Connection: keep-aliveContent-Type: text/htmlLast-Modified: Thu, 18 Apr 1996 17:39:05 GMTContent-Length: 2543 <HTML> Some data... blah, blah, blah </HTML>
Internet TechnologiesHTTP Response
HTTP version Status code Reason phrase Headers
Data
© 2004 the University of Greenwich 11
Internet TechnologiesHTTP Server Status Codes
Code Description
200 OK
201 Created
301 Moved Permanently
302 Moved Temporarily
400 Bad Request – not understood
401 Unauthorized
403 Forbidden – not authorized
404 Not Found
500 Internal Server Error
© 2004 the University of Greenwich 12
Internet TechnologiesHTTP
• HTTP is a stateless protocol
• Each HTTP request is independent of previous and subsequent requests
• HTTP 1.1 introduced keep-alive for efficiency
• Statelessness has a big impact on how scalable applications are designed
© 2004 the University of Greenwich 13
Internet TechnologiesCookies
• A mechanism to store a small amount of information (up to 4KB) on the client
• Cookies are associated with a specific web site• A cookie may be sent from a web server to a web client
in the HTTP response header• Cookies are returned to the web server in all subsequent
HTTP requests• Can last for only for the duration of the session (until
browser is closed) or may persist across sessions• Can expire some time in the future• Can persist indefinitely
© 2004 the University of Greenwich 14
Internet TechnologiesHTTPS
• A secure version of HTTP
• Allows client and server to exchange data with confidence that the data was neither modified nor intercepted
• Uses Secure Sockets Layer (SSL)/Transport Layer Security (TLS)
© 2004 the University of Greenwich 15
Internet TechnologiesURIs, URLs and URNs
• Uniform Resource Identifier (URI = URL or URN)• Generic term for all textual names/addresses
• Uniform Resource Locator (URL)• The set of URI schemes that have explicit instructions
on how to access the resource over the Internet, e.g. http, ftp, gopher
• Uniform Resource Name (URN) 1) A URI that has an institutional commitment to
availability, etc.2) A particular scheme intended to identify resources
e.g. urn:schemas:httpmail:subject
© 2004 the University of Greenwich 16
Internet TechnologiesMultipurpose Internet Mail Extensions (MIME)
• Defines types of data/documents• text/plain• text/html• image/gif• image/jpeg• audio/x-pn-realaudio• audio/x-ms-wma• video/x-ms-asf• application/octet-stream
© 2004 the University of Greenwich 17
Internet TechnologiesMIME
• Specifies character sets, e.g. ASCII
• Supports multi-part messages
• Originally designed for email, but also used in other places, such as HTTP
© 2004 the University of Greenwich 18
Internet TechnologiesBrowsers
• Client-side application• also known as a User Agent
• Forms HTTP requests on behalf of users• Can render HTML
• usually graphical but may be text only
• Popular browsers:• Mozilla• Netscape• Internet Explorer• Opera
• Assistive technology• specialised to provide access for people with disability
© 2004 the University of Greenwich 19
Internet TechnologiesClients & Servers
• Client and Server computers both have:• CPU• Memory• I/O
• Disks• Network
• Bus• Multi-tasking operating system• Applications
© 2004 the University of Greenwich 20
Internet TechnologiesClients & Servers
• Clients• Generally supports a single user• Optimized for responsiveness to user• User interface, graphics
• Servers• Supports multiple users• Optimized for throughput• More: CPUs (SMP), memory, disks (SANs), I/O• Provide services (e.g. Web, file, print, database,
e-mail, fax, transaction, telnet, directory)
© 2004 the University of Greenwich 21
Internet TechnologiesProxy Servers & Firewalls
• Proxy Server • A server that sits between a client (running a browser)
and the Internet• Improves performance by caching commonly used
Web pages• Can filter requests to prevent users from accessing
certain Web sites
• Firewall• A server that sits between a network and the Internet
to prevent unauthorized access to the network from the Internet
© 2004 the University of Greenwich 22
Internet TechnologiesNetworks
• Network = an interconnected collection of independent computers
• Why have networks?• Resource sharing• Reliability• Cost savings• Communication
• Web technologies add:• New business models: e-commerce, advertising• Entertainment• Applications without a client-side install
© 2004 the University of Greenwich 23
Internet TechnologiesNetworks
• Network scope• internet: a collection of connected networks• Internet: a specific world-wide network based on
TCP/IP, used to connect companies, universities, governments, organizations and individuals. Originated as ARPANET, funded by the US DoD.
• intranet: a network based on Internet technologies that is internal to a company or organization
• extranet: a network based on Internet technologies that connects one company or organization to another
© 2004 the University of Greenwich 24
Internet TechnologiesNetworks
• Network technology is largely determined by scale:• Local Area Network (LAN): Span up to a few
kilometers. Bus vs. ring topologies• Wide Area Networks (WAN): Can span a
country or continent. WANs use routers as intermediate nodes to connect transmission lines
© 2004 the University of Greenwich 25
Internet TechnologiesNetworks
• Network technology• Broadcasting
• Packets of data are sent from one machine and received by all computers on the network
• Multicast: packets are received by a subset of the machines on a network
• Point-to-point• Packets have to be routed from one machine to another;
there many be many paths
• In general, geographically localized networks use broadcasting, while disperse networks use point-to-point
© 2004 the University of Greenwich 26
Internet TechnologiesNetworks
ApplicationLayer
PresentationLayer
SessionLayer
TransportLayer
NetworkLayer
Data LinkLayer
PhysicalLayer
InternetLayer
ApplicationLayer
Telnet FTP SMTP DNS RIP SNMP HTTP
IP
Host-to-HostTransport
LayerTCP UDP
TokenRing
Ethernet ATMFrameRelay
NetworkInterface
Layer
OSI Model Layers
TCP/IP Protocol
Architecture Layers
TCP/IP Protocol Suite
ARPICMPIGMP
Telnet FTP SMTP DNS RIP SNMP
TCP
© 2004 the University of Greenwich 27
Internet TechnologiesNetwork Protocol Stack
HTTP
TCP
IP
Ethernet
HTTP
TCP
IP
Ethernet
© 2004 the University of Greenwich 28
Internet TechnologiesNetworks - Internet Layer
• Internet Protocol (IP)
• Responsible for getting packets from source to destination across multiple hops
• Not reliable
• IP address: 32 bit value usually written in dotted decimal notation as four 8-bit numbers (0 to 255); e.g. 130.50.12.4
© 2004 the University of Greenwich 29
Internet TechnologiesNetworks - Transport Layer
• Provides efficient, reliable and cost-effective service
• Uses the Sockets programming model• Ports identify application
• Well-known ports identify standard services (e.g. HTTP uses port 80, SMTP uses port 25)
• Transmission Control Protocol (TCP)• Provides reliable, connection-oriented byte stream
• UDP• Connectionless, unreliable
© 2004 the University of Greenwich 30
Internet TechnologiesNetworks - Application Layer
• Telnet: Remote sessions
• File Transfer Protocol (FTP)
• Network News Transfer Protocol (NNTP)
• Simple Network Management Protocol (SNMP)
• Simple Mail Transfer Protocol (SMTP)
• Post Office Protocol (POP3)
• Interactive Mail Access Protocol (IMAP)
© 2004 the University of Greenwich 31
Internet TechnologiesNetworks - Domain Name System (DNS)
• Provides user-friendly domain names, e.g. www.msn.com
• Hierarchical name space with limited root names
• DNS servers map domain names to IP addresses
.com .net .gov .edu
.org .mil .jp .de
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Internet TechnologiesExtensible Markup Language (XML)
• Represents hierarchical data
• A meta-language: a language for defining other languages
• Extensible
• Useful for data exchange and transformation
• Simplified version of SGML
© 2004 the University of Greenwich 33
Agenda
• Internet Technologies
• Programming Languages and Paradigms
• Programming the Web
• .NET Overview
© 2004 the University of Greenwich 34
Programming Languages
• Machine code• Assembly language• High-level languages
• Fortran, LISP, Cobol• C, Pascal, Basic, Smalltalk• C++, Eiffel• Java, C#
• Scripting languages• Shell scripts, Perl, TCL, Python, JavaScript, VBScript
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Programming Paradigms
• Unstructured programming
• Structured programming
• Object-oriented programming
• Component-based programming
• Event-based programming
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Programming ParadigmsUnstructured Programming
• See “Go To Statement Considered Harmful” at http://www.acm.org/classics/oct95/
© 2004 the University of Greenwich 37
Programming ParadigmsStructured Programming
• Sequence• Conditional
• if then else• switch
• Looping• for i from 1 to n• do while• do until
• Functions• Exceptions
© 2004 the University of Greenwich 38
Programming ParadigmsObject-Oriented Programming
• Objects have data and behavior• Data: members, fields, variables, slots, properties
• Behavior: methods, functions, procedures
• Using objects is easy• First instantiate the type of object desired
• Then call its methods and get/set its properties
• Designing new types of objects can be hard• Design goals often conflict: simplicity, functionality,
reuse, performance
© 2004 the University of Greenwich 39
Programming ParadigmsObject-Oriented Programming
• Key object-oriented concepts• Identity• Encapsulation
• Data + behavior• Information hiding (abstraction)
• Classes vs. instances• Polymorphism• Interfaces• Delegation, aggregation• Inheritance• Patterns
© 2004 the University of Greenwich 40
Programming ParadigmsComponent-Based Programming
• Components• Independent modules of reuse and deployment• Coarser-grained than objects
(objects are language-level constructs)• Includes multiple classes• Often language-independent
• In the general case, the component writer and the component user don’t know each other, don’t work for the same company, and don’t use the same language
© 2004 the University of Greenwich 41
Programming ParadigmsComponent-Based Programming
• Component Object Model (COM)• Initial Microsoft standard for components• Specifies a protocol for instantiating and using
components in-process, across processes or across machine boundaries
• Basis for ActiveX, OLE, and many other technologies• Can be created in Visual Basic, C++, .NET, …
• Java Beans• Java standard for components• Not language-independent
© 2004 the University of Greenwich 42
Programming ParadigmsEvent-Based Programming
• When something of interest occurs, an event is raised and application-specific code is executed
• Events provide a way for you to hook in your own code into the operation of another system
• Event = callback• User interfaces are all about events
• onClick, onMouseOver, onMouseMove…
• Events can also be based upon time or interactions with the network, operating system, other applications, etc.
© 2004 the University of Greenwich 43
Agenda
• Internet Technologies
• Programming Languages and Paradigms
• Programming the Web
• .NET Overview
© 2004 the University of Greenwich 44
Programming the WebClient-Side Code
• What is client-side code?• Software that is downloaded from Web server to
browser and then executes on the client
• Why client-side code?• Better scalability: less work done on server• Better performance/user experience• Create UI constructs not inherent in HTML
• Drop-down and pull-out menus• Tabbed dialogs
• Cool effects, e.g. animation• Data validation
© 2004 the University of Greenwich 45
Programming the WebClient-Side Technologies
• DHTML – HTML + CSS + JavaScript + DOM• COM
• ActiveX controls• COM components• Remote Data Services (RDS)
• Java applets• Plug-ins, e.g. shockwave• Helpers• Remote Scripting, e.g. AMF
© 2004 the University of Greenwich 46
Programming the WebDynamic HTML (DHTML)
• Script that is embedded within an HTML page• Usually written in JavaScript (ECMAScript,
JScript) for portability• Internet Explorer also supports VBScript and other
scripting languages
• Each HTML element is an object in the DOM that has associated events (e.g. onClick)
• Script provides code to respond to browser events
© 2004 the University of Greenwich 47
Programming the WebDHTML
• DHTML Document Object Model (DOM)
window
history document location screen
all location children selectionforms body links
text buttonradio textarea select
password
file
checkbox submit
resetoption
navigator framesevent
© 2004 the University of Greenwich 48
Programming the WebActiveX
• Based on COM• Native only to Internet Explorer
• Supported in other browsers with a plug-in
• Good when you know your users (e.g. intranet) or can specify which browser to use• Not so good when you don’t (e.g. the Internet)
• Small, efficient code• Like Flash but not so pretty
© 2004 the University of Greenwich 49
Programming the WebJava Applets
• Based on Java bytecode
• Held great promise as a portable, pain-free way to download client-side code: • “Write once, run anywhere”
• Fairly safe: code runs in a “sandbox”
• Compatibility and performance issues have prevented common usage
© 2004 the University of Greenwich 50
Programming the WebServer-Side Code
• What is server-side code?• Software that runs on the server, not the client• Receives input from
• URL parameters• HTML form data• Cookies• HTTP headers
• Can access server-side databases, e-mail servers, files, mainframes, etc.
• Dynamically builds a custom HTML response for a client
© 2004 the University of Greenwich 51
Programming the WebServer-Side Code
• Why server-side code?• Availability
• You can reach the Internet from any browser, any device, any time, anywhere
• Manageability• Does not require distribution of application code• Easy to change code
• Security• Source code is not exposed• Once user is authenticated, can only allow certain actions
• Scalability• Web-based 3-tier architecture can scale out
© 2004 the University of Greenwich 52
Programming the WebServer-Side Technologies
• Common Gateway Interface (CGI)• not language specific
• Internet Server API (ISAPI)• netscape Server API (NSAPI)
• Active Server Pages (ASP)• now obsolete
• Java Server Pages (JSP)• PHP Hypertext Processor (PHP)• Cold Fusion (CFM)
• actually J2EE with the arrival of ColdFusion MX• ASP.NET
© 2004 the University of Greenwich 53
Programming the Web Active Server Pages (ASP)
• Technology to easily create server-side applications
• ASP pages are written in a scripting language• usually VBScript but also Jscript or PerlScript
• An ASP page contains static HTML interspersed with server-side code
• ASP script is commonly used to access and update a database• 3-tier systems
© 2004 the University of Greenwich 54
Programming the WebASP
HTTP request(form data, HTTP
header data)
HTTP responseHTML, XML
ASP page(static HTML +
server-side logic)
© 2004 the University of Greenwich 55
Agenda
• Internet Technologies
• Programming Languages and Paradigms
• Programming the Web
• .NET Overview
© 2004 the University of Greenwich 56
.NET Overview
• Introduction to .NET
• Web Services
• The .NET Framework
• Common Language Runtime
• Windows Forms
• Web Forms
• ADO.NET
• Languages
© 2004 the University of Greenwich 57
Introduction to .NETWhat is .NET?
• A vision• web sites will be joined by web services• new smart devices will join the PC• user interfaces will become more adaptable
and customizable• enabled by web standards
© 2004 the University of Greenwich 58
• A platform• the .NET Framework• Visual Studio.NET• .NET Enterprise Servers
• database, messaging, integration, commerce, proxy, security, mobility, orchestration, content management
• .NET Building Block Services• Passport• .NET My Services (“Hailstorm”)
• goal: make it incredibly easy to build powerful web applications and web services
Introduction to .NETWhat is .NET?
} The focus of this course
© 2004 the University of Greenwich 59
• A business model• software as a service• subscription-based services• application hosting
Introduction to .NETWhat is .NET?
© 2004 the University of Greenwich 60
Introduction to .NETThe .NET Platform
Web Form
.NET Framework
Windows and Linux and…
Web Service
.NET FoundationWeb Services
Your InternalWeb Service
Third-PartyWeb Services
.NET EnterpriseServers
Clients Applications
Protocols: HTTP,HTML, XML, SOAP, UDDI
Tools:Visual Studio.NET,
Notepad
© 2004 the University of Greenwich 61
Web Services
• A programmable application component accessible via standard web protocols
• The centre of the .NET architecture
• Exposes functionality over the Web
• Built on existing and emerging standards• HTTP, XML, SOAP, UDDI, WSDL, …
© 2004 the University of Greenwich 62
Web ServicesEvolution of the Web
Generation 1Static HTML
HTML
Generation 2Web Applications
HTML
HTML, XML
HTML, XML
Generation 3Web Services
© 2004 the University of Greenwich 63
• A set of technologies for developing and using components to create:• web forms• web services• windows applications
• Supports the software lifecycle• development• debugging• deployment • maintenance
The .NET FrameworkWhat Is the .NET Framework?
© 2004 the University of Greenwich 64
Common Language Specification
Common Language Runtime
VB C++ C#
ASP.NET: Web Servicesand Web Forms
JScript …
WindowsForms
.NET Framework Base Classes
ADO.NET: Data and XML
Visu
al Stu
dio
.NE
T
The .NET FrameworkThe .NET Framework and Visual Studio.NET
© 2004 the University of Greenwich 65
System.Data
DesignOLEDB
SQLTypesSQL
System
GlobalizationDiagnostics
ConfigurationCollections
ResourcesReflection
NetIO
ThreadingText
ServiceProcessSecurity Runtime
InteropServicesRemotingSerialization
System.Xml
XPathXSLT Serialization
System.Web
Configuration SessionStateCaching Security
ServicesDescriptionDiscoveryProtocols
UIHtmlControls
WebControlsSystem.Drawing
ImagingDrawing2D
TextPrinting
The .NET Framework.NET Framework Classes
System.Windows.FormsForm Button
MessageBox ListControl
© 2004 the University of Greenwich 66
Common Language RuntimeGoals
• Development services• deep cross-language interoperability• increased productivity
• Deployment services• simple, reliable deployment• fewer versioning problems – NO MORE ‘DLL HELL’
• Run-time services• performance • scalability • availability
• reliability• security• safety
© 2004 the University of Greenwich 67
Source CodeSource Code
C++, C#, VB or any .NET language
csc.exe or vbc.exe
Compiler
AssemblyAssembly
DLL or EXE
Common Language RuntimeCompilation
© 2004 the University of Greenwich 68
• Assembly• logical unit of deployment• contains manifest, metadata, MSIL and resources
• Manifest• metadata about the components in an assembly
(version, types, dependencies, etc.)
• Type metadata• completely describes all types defined in
an assembly: properties, methods, arguments, return values, attributes, base classes, …
Common Language RuntimeAssemblies
© 2004 the University of Greenwich 69
Common Language RuntimeAssemblies
• Microsoft Intermediate Language• MSIL or IL• all languages compile to IL (managed code)• IL is always compiled to native code before
being executed
• Resources• data, images, audio, etc.
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Common Language RuntimeExecution Model
CLR
VBSource code
Compiler
C++C#
Assembly AssemblyAssembly
Operating System Services
MSIL
Common Language Runtime JIT Compiler
Compiler Compiler
Nativecode
ManagedCode
ManagedCode
ManagedCode
UnmanagedCode
CLR Services
Ngen
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Common Language RuntimeServices
• Code management• Conversion of MSIL to
native code • Loading and execution of
managed code • Creation and
management of metadata• Verification of type safety• Insertion and execution of
security checks• Memory management
and isolation
• Garbage collection• Handling exceptions
across languages• Interoperation
between .NET Framework objects and COM objects and Win32 DLLs
• Automation of object layout for late binding
• Developer services (profiling, debugging, etc.)
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• Common Type System (CTS)• superset of the data types used by most modern programming
languages
• Common Language Specification (CLS)• subset of CTS that allows code written in different languages to
interoperate
• What languages?• Microsoft - C#, C++, VB.NET, JScript• third party
• Perl, Ada, Cobol, Java, Fortran• Eiffel, Smalltalk, Scheme, Oberon, Haskell, Python,…• only practical if the language supports some sort of encapsulation
Common Language RuntimeMultiple Language Support
© 2004 the University of Greenwich 73
Common Language RuntimeApplications
• An application consists of one or more assemblies• How does one assembly bind to another?
• based upon metadata and policy• local (preferred)• Assembly Global Cache (AGC) (accurate garbage collection?)
• Multiple versions of an assembly may exist on the same machine• easier software deployment, updates and removal• multiple versions of an assembly can even be used by
the same application• like this is a new thing?
© 2004 the University of Greenwich 74
Common Language RuntimeSecurity
• Evidence-based security (authentication)
• Based on user identity and code identity
• Configurable policies
• Imperative and declarative interfaces
© 2004 the University of Greenwich 75
Windows Forms
• Framework for building rich clients
• Built upon .NET Framework, languages
• Rapid Application Development (RAD)
• Visual inheritance• Anchoring and docking• Rich set of controls
• Extensible controls• Data-aware• Easily hooked into
Web Services• ActiveX support• Licensing support• Printing support• Advanced graphics
© 2004 the University of Greenwich 76
Web Forms• Built with ASP.NET
• logical evolution of ASP• similar development model: edit the page and go
• Requires less code• actually more code but less programming
• New programming model• event-driven/server-side controls• rich controls (e.g. data grid, validation)• data binding• controls generate browser-specific code• simplified handling of page state
© 2004 the University of Greenwich 77
Web Forms
• Allows separation of UI and business logic• separation of concerns is a good thing• cleaner, more maintainable code
• Uses .NET languages• not just scripting
• Easy to use components
• XCOPY/FTP deployment
• Simple configuration (XML-based)
© 2004 the University of Greenwich 78
Web Forms
• Caching (pages, fragments, custom)
• Scalable session state management
• Tracing support
• ASP.NET is extensible• no ISAPI / ASP dichotomy
• Automatic process rollover
• Forms-based authentication
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• Similar to ADO, but better factored• Language-neutral data access• Supports two styles of data access
• disconnected• forward-only, read-only access
• Supports data binding• DataSet: a collection of tables• Can view and process data relationally (tables) or
hierarchically (XML)
ADO.NETActiveX Data Objects
© 2004 the University of Greenwich 80
Languages C#
• New language created for .NET• a Java rip-off
• Safe, productive evolution of C++• but not as safe as Java until M$ sort out the
exceptions
• Key concepts:• component-oriented• everything is an object• robust and durable code• preserving your investment
• Submitted to the ECMA for standardization
© 2004 the University of Greenwich 81
Languages Visual Basic.NET
• Modernizes and simplifies Visual Basic• because the old VB was pants• inheritance• threading• exception handling
• Support for late binding• whatever that is
• Actually just C# with a different syntax• and some of the fancy stuff missing because VB
programmers are unlikely to be clever enough to use them anyway
© 2004 the University of Greenwich 82
Conclusion• dotNET is pretty neat really even if it does come
from M$• A whole lot of good ideas have been gathered
together without the accumulation of legacy bugware that tends to plague other M$ products
• Although .NET initially looked like another attempt by Mr Evil to take over the world it is remarkably open and standard compliant compared with other M$ offerings
• The best bit is probably Visual Studio with it’s tooled up approach to application development
© 2004 the University of Greenwich 83
More Resources• HTTP
• http://msdn.microsoft.com/library/periodic/period96/protocol.htm• HTTP Essentials, Stephen Thomas, 2001, Wiley,
ISBN 0471-39823-3
• Cookies• http://msdn.microsoft.com/library/default.asp?URL=/library/
partbook/instantj/cookies.htm
• MIME• http://www.ufaq.org/navcom/mime_tutorial.html• http://www.irvine.com/~mime/
• Networks• http://msdn.microsoft.com/library/periodic/period99/ntp99b3.htm
© 2004 the University of Greenwich 84
More Resources• XML
• http://msdn.microsoft.com/xml/default.asp• http://www.w3.org/XML/• Essential XML, Don Box, Aaron Skonnard, John Lam,
Addison Wesley, 2000, ISBN 0-201-70914-7
• .NET• http://www.microsoft.com/net/• http://msdn.microsoft.com/net/• http://www.gotdotnet.com• msnews.microsoft.com news server
• microsoft.public.dotnet.general newsgroup
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