frameworks

1. BY-Teach4u.in

2. The .NET Framework
 What is Microsoft .NET?
 A programming model: CLR + Classes
 XML Web services
 Server and Client software and tools

3. Common Language Runtime (CLR)
 It’s a VM (Java-like) on which any (supported)
language can run.
 Why a VM?
 Memory Protection
 Cross-language
 Support for strong-typing across languages (the data are
typed)
 Thread support
 JIT compilation in the VM

4. Languages in CLR
 Language of choice is C# (“C-sharp”) a Java-like language
 No inner classes
 Better type checking
 Other languages will run on CLR, but only within the CLR
constraints
 Visual Basic, JScript are full fledged CLR languages
 For example, only C++ that is VM-safe will run
 That subset looks much like C#
 Under CLR, all languages get object features
 Inheritance used extensively
 Every language gets constructors

5. Languages compile to MSIL
 Languages compile to MSIL (Microsoft Intermediate
Language)
 Can you say “bytecodes”?
 MSIL is shipped in portable executable (PE) units
 Can you say .class files or applets?
 An application is made up of assemblies

6. Assemblies
 In general, a static
assembly can consist of
four elements:
 The assembly manifest,
which contains assembly
metadata.
 Type metadata.
 Microsoft intermediate
language (MSIL) code
that implements the
types.
 A set of resources.

7. Assemblies can be spread across .NET

8. Assemblies are the security unit
 Each assembly has a set of corresponding grants
 Each grant allows certain permissions
 DnsPermission, Environment, FileDialog, FileIO,
IsolatedStorage, Reflection, Registry, Security, UI,
WebPermission, SocketPermission
 The set of grants establishes a security policy

9. Class Library
 Data classes support persistent data management and
include SQL classes.
 XML classes enable XML data manipulation and XML
searching and translations.
 Windows Forms support development of Windows
GUI applications across CLR
 Web Forms include classes that enable you to rapidly
develop web GUI applications.

10. System.Object
 Public methods:
 Equals
 GetHashCode
 GetType
 ToString
 Overriding inherited behaviors is common

11. Web, Windows, Whatever
 Part of the idea is to smooth transitions between
Windows and Web
 Web interfaces become easier for Windows developers
 Windows apps become .NET Web-based apps

12. Data <-> XML, Everywhere
 All CLR data can be serialized
to XML
 All XML can be expanded into
CLR data
 Thus, anything can be shipped
around on the Web
 Typing through XML Schema

13. XML Schema
<xsd:complexType name="Person">
<xsd:sequence>
<xsd:choice>
<xsd:element name="name" type="xsd:string"
xsi:nillable="true" />
<xsd:element name="id" type="xsd:string" />
</xsd:choice>
<xsd:any processContents="lax"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="AgedPerson">
<xsd:complexContent mixed="false">
<xsd:extension base="target:Person">
<xsd:choice>
<xsd:element name="age" type="xsd:double" />
<xsd:element name="timeOnEarth" type="xsd:double" />
</xsd:choice>
</xsd:extension>
</xsd:complexContent>
</xsd:complexType>
<xsd:element name="don" type="target:Person" />

14. Example Instance
<ns:don
xmlns:ns="uuid:048b2fa1-d557-473f-ba4c-
acee78fe3f7d"
>
<name>Don Box</name>
<niceStuffForDon/>
</ns:don>

15. Second Example Instance
<ns:don
xmlns:ns="uuid:048b2fa1-d557-473f-ba4c-acee78fe3f7d"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns:AgedPerson"
>
<name>Don Box</name>
<niceStuffForDon/>
<age>26</age>
</ns:don>

16. A Simpler Schema
<element name="Book">
<complexType>
<element name="author" type="xsd:string"/>
<element name="preface" type="xsd:string"/>
<element name="intro" type="xsd:string"/>
</complexType>
</e:Book>

17. Another Example Instance
<e:Book>
<author>Henry Ford</author>
<preface>Prefatory text</preface>
<intro>This is a book.</intro>
</e:Book>

18. XML Schema Defined Types

19. Class Library Data Hierarchy

20. Reading in XML Data
XmlReader reader
= new
XmlTextReader("http://foo.com/don.xsd");
XmlSchema schema = XmlSchema.Load(reader, null);
schema.Compile(null); // turn xml into objects
reader.Close();

21. ALL Interprocess Communication via SOAP
 ALL Interprocess communication (across network or
on same machine) is through SOAP
 Simple Object Access Protocol
 It’s a way of exchanging data and even calling other
methods/threads, all via XML and plain old HTTP
requests

22. Example SOAP Request
POST /StockQuote HTTP/1.1
Host: www.stockquoteserver.com
Content-Type: text/xml; charset="utf-8"
Content-Length: nnnn
SOAPAction: "Some-URI"
<SOAP-ENV:Envelope
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<SOAP-ENV:Body>
<m:GetLastTradePrice xmlns:m="Some-URI">
<symbol>DIS</symbol>
</m:GetLastTradePrice>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>

23. Example SOAP Response
HTTP/1.1 200 OK
Content-Type: text/xml; charset="utf-8"
Content-Length: nnnn
<SOAP-ENV:Envelope
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"/>
<SOAP-ENV:Body>
<m:GetLastTradePriceResponse xmlns:m="Some-URI">
<Price>34.5</Price>
</m:GetLastTradePriceResponse>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>

24. ASP.NET
 ASP =>
Active Server Pages
 Put most of the computation
in the server
 Very simple model to use
 ADO.NET is the database
connection part

25. Calling Web Services
 Any class can be converted into an XML Web Service with just a
few lines of code, and can be called by any SOAP client.

26. Take-away lessons
 VM’s are important
 Even Microsoft thinks so
 Distributed apps are important, but to do so requires
standard protocols
 Ways of serializing data
 Ways of doing RPC

27. Limitations of the .NET Framework
 What if you’re not on the network?
 Maybe that’s not an issue?
 Mapping between XML and any object is hard
 Any object is controlled by compiler.
XML can be written by anybody with a text editor.
 There’s a whole bunch of class support for modified
serializers and compilers