.net

Microsoft .NET









Junhui wang

July 10, 2003

Outline

 Introduction to MS.NET

 .NET Framework

What is MS .NET

Old: .NET is the Microsoft platform for XML

Web service.

New: .NET is the set of Microsoft

technologies for connecting your world of

information,people,systems and devices.

.NET is infused into the Microsoft platform

providing the ability to build,host,deploy and

consume XML Web service connected

solutions.

Why MS .NET

.Interoperability between languages and

execution environments

.Uniformity in schema or formats for

Data Exchange using XML,XSL

.Extend or use existing code that is valid

.Programming complexity of

environment is reduced

Services provided by MS .NET

A new run-time environment, the .NET Framework

A new programming model for constructing HTML

pages, named ASP.NET

A new way for Internet servers to expose functions

to any client, named XML Web services

Windows Forms, a new way of writing rich client

applications using the .NET framework

Support for db access within the .NET

framework,namely ADO.NET

Support for handling XML documents and streams

A standardized mechanism for signaling

asynchronous events

Support for writing multithreaded code

Support for writing your own Windows Forms and

Web Forms controls

Component of MS .NET

.NET spans clients,servers and develop tools

 .NET framework

 .Developer tools

such as MS visual studio.NET 2003

 . A set of servers

including MS Windows server 2003,MS

SQL server

 .Client software

such as Windows XP

What is .NET Framework

.NET framework is an integral Windows component for

building and running all kinds of software,including

web-based applications,smart client applications and

XML Web services.

. Support over 20 different programming languages.

. Manages much of the plumbing involved in developing

software,enabling developers to focus on the core

business logic code.

. Makes it easier than ever before to build,deploy,and

administer secure,robust and high-performing

applications.

Component of .NET Framework

. Common Language Runtime(CLR)

. A unified set of class libraries

.NET Framework Architecture

 What is .NET anyway?









Microsoft .NET provides

prefabricated

infrastructure for solving

the common problems

of writing Internet

software.

Common Language Runtime

Provide the common services for .NET framework

Run-time

.Language integration

.Security enforcement

.Memory management

.Process management

. Thread management

Developing time

.Life-cycle management

.Strong type naming

.Cross-language exception handling

. Dynamic binding reduce the amount of code

CLR: Execution Model

Source VB C# C++

code

Compiler Compiler Compiler Unmanaged

Component

Managed Assembly Assembly Assembly

code IL Code IL Code IL Code







Common Language Runtime



JIT Compiler



Native Code



Operating System Services

Class Library

ASP.NET: building Web applications and

Web services

ADO.NET: connecting applications to

database

Windows Forms: an environment for

building smart client applications

System Class:

XML,security,network,messaging

ADO.NET

ADO.NET features



 Designed for disconnected access

 Can model data logically!

 The DataSet replaces the RecordSet

 DataSet can contain multiple tables

Core Concepts and Architecture

 The ADO.NET Object Model

 DataSet objects

 Managed providers

 ADO.NET-related Namespaces

 System.Data

 System.Data.ADO

 System.Data.Internal

 System.Data.SQL

 System.Data.SQLTypes

ADO.NET Objects

.NET Applications





Data Set Data Reader



Command Object



Connection Object



Managed Data Provider

(OLEDB)



Database

ADO.NET and Managed Providers

 A collection of classes for accessing data sources:

 Microsoft SQL Server™ 2000, SQL Server 7, and MSDE



 Any OLE Database (OLE DB) providers



 Including: Oracle, JET, and SQL OLE DB Providers



 Establish connection between DataSets and data stores



 Two managed providers:

 ADO: via the System.Data.ADO namespace



 SQL Server: via the System.Data.SQL namespace



 System.Data.ADO is the ADO.NET managed provider

Connection with a Connection Object

 A connection object represents a unique session with

a data source.

 Connection string: database, OLE DB provider,

password, etc.

 Use the Open/Close method to open/close a

connection.

Connection String

 Containing information about database, OLE DB

provider, password, if any, security, etc.

 For Jet database:

 Provider=Microsoft.Jet.OLEDB.4.0;Persist Security



info = False;Data Source=c:\ …\Nwind.mdb

Connection Object

 Example:

 dim strConn as string ="Provider=Microsoft.Jet.OLEDB.4.0;Data Source =

c:\sales2k.mdb"

 dim objConn as new ADOConnection(strConn)

 objConn.open()



 Basic Methods:

 Open, Close

Command Object

 The command object allows us to execute a SQL statement.

 Properties:

 CommandType: SQL or stored procedure



 CommandText: SQL statement



 Connection

 Basic Methods:

 ExecuteReader: Creates a DataReader object that contains



the results of the query.

 ExecuteNonQuery: Execute SQL’s INSERT, DELETE, UPDATE



statements.

DataReader Object

 It is read-only and forward-only cursor.

 Basic Methods:

 Read: Reads the current record and advances the



pointer to the next record.

 Close: Closes the dataReader.

ADODataReader Sample

// Code for creating the ADOConnection “adoConn” not shown

String myQuery = “SELECT * FROM Customers”;

adoConn.Open();

ADOCommand myCmd = new ADOCommand( myQuery,adoConn );

// Declare the ADODataReader...

ADODataReader myDataReader;



// Instantiate the ADODataReader with Execute(...) ...

myCmd.Execute(out myDataReader);



// Always call Read before accessing data.

while(myDataReader.Read())

{ //code

}



// Always Close the reader and the connection when done

myDataReader.Close();

adoConn.Close();

DataSet Object

 A DataSet object can hold several tables and

relationships between tables.

 A DataSet is a set of disconnedted data. Data is

extracted from the database and stored in the

DataSet object. Updates to the DataSet must copy

back to the database to make the changes

permanent.

DataSet and Related Objects

DataView





DataSet

DataTable

DataTable





Command





DataAdapter





Connection

DataSet and Related Objects

 DataSet: Can contain multiple tables and

relationships.

 DataTable object: Represents a table in the dataset.

 DataAdapter: This the object used to pass data

between the database and the dataset. The Fill

method copies the data into the dataset, and the

Update method copies the updates back into the

database.(datasetcom)

 DataView: This represents a specific view of the

DataTables held in the dataset.

System.Data—DataSet and XML

 DataSet can read/write XML for its data and/or schema

 Means: You can create or modify a DataSet using XML!



 XML-related DataSet methods for reading:

 ReadXml: Reads an XML schema and data into the



DataSet

 ReadXmlData: Reads XML data into the DataSet



 ReadXmlSchema: Reads an XML schema into the



DataSet

 And for writing: WriteXml, WriteXmlData,

WriteXmlSchema

Methods of Reading and Writing XML

// Code for creating the DataSet mds and loading the

// DataSet from a data source not shown.



String oFile = “C:\\My_ADO.NET\\myXmlOutput.xsd”;

String iFile = “C:\\My_ADO.NET\\myXmlInput.xsd”;



// Write the DataSet’s XMLSchema to an XML Document

mds.WriteXmlSchema( oFile );



// Read/Upload XML Data into the DataSet

mds.ReadXmlData( iFile, true );



// Write the existing Data to an XML Document

mds.WriteXmlSchema( “C:\\My_ADO.NET\\myXmlData.txt );



// Or output the XML Data using the XmlData property!

Console.WriteLine( mds.XmlData );

ASP.NET

ASP.NET

 ASP.NET is a new programming framework designed to make web

apps easier to:

 Build, Deploy, Run



 Radical advancement of today’s ASP

 Broader programming language support



 Visual Basic.NET, Jscript.NET, C#



 Form-based programming model(similar to VB form)



 Event driven programming



 Programmable control



 New application model



XML Web service

Mobile Web device support

 Better reliability and recovery



 Excellent Visual Studio support

ASP.NET Cont.

 Improved performance & scalability

 ASP.NET is compiled, not interpreted



 Rich output caching



 Session state can now be shared across a web form

of ASP.NET servers

 .NET State Server Process manages state



 ASP.NET detects and recovers from problems

 Access violations, memory leaks, dead

ASP.NET Application



 Web forms:building powerful forms-based

Web pages

 XML Web Services :providing the means to

access server functionality remotely.

 Combinations

Web Forms

 The visual component(Web Form Pages)

consists of a file(.aspx extension)

(1)static HTML

(2) ASP.NET server controls

HTML server controls

Web server controls

Validation controls

user controls

(3) both.

 The logic for the Web Form page(code)

separate file(.aspx.vb or .aspx.cs extension)

.NET Web Services

 NET is built on Internet standard protocols

 Uses Framework classes, such as

 System.Web.Services

 Enables communication through open

standards

 XML

 Service description expressed with WSDL

 SOAP

 Basic wire format

 Universal Description Discovery Integration

(UDDI)

 HTTP

Define XML Web Services



 To create an XML Web service, simply write a .NET object

as if it were being accessed directly by local clients, mark

it with an attribute that says this object should be

available to Web clients, and ASP.NET will do the rest.

 ASP.NET automatically hooks up a prefabricated

infrastructure that accepts incoming requests through

HTTP and maps them to calls on the object

ASP.net for XML Web Services

• Creating a Web service

1. Create a file with an .asmx file name extension .

2.Within the file ,declare the XML web service using

directive

3.Define the XML service methods that compose the

functionality of the XML Web service

• Creating a discovery file

Create a XML document with a .DISCO extension

(not compulsory to create)

Server-side view of XML Web services

1. HTTP requests arrive, with Windows 2000 server machine

method name and with .NET

parameters encoded in

URL or separate XML.

2. ASP.NET creates object

specified in .ASMX file.

5. ASP.NET converts results to

XML and returns to client 3. ASP.NET calls specified

via HTTP. method on object.

4. Object returns .NET object

results to ASP.NET.

Method 1

.

.

Method N

Client-side view of XML Web services

0. At programming time, a developer generates proxy

object code from a description of an XML Web service.

Client Program

1. At run time, client creates proxy object.

2. Client calls method on proxy.





Proxy

To/from server

3. Proxy converts call to HTTP via Internet

5. Client receives and XML and sends it to

return value server over the Internet.

from proxy.

4. Proxy receives results in

XML over HTTP and converts

to function return value.

Example: building a Web Service





Imports System

Imports System.Web.Services



Public Class TimeService : Inherits WebService



Public Function GetTime (ShowSeconds as Boolean) As String



If (ShowSeconds = TRUE) Then

return DateTime.Now.ToLongTimeString

Else

return DateTime.Now.ToShortTimeString

End if



End Function



End Class

Describing XML Web Services by WSDL File

 To develop client applications that uses the XML Web services,

programmers need a description of what the service does and how to

use the service (e.g. methods exposed, parameters required by those

methods, protocols supported)

 Problem: a universal approach not restricted to the MS world of

describing a service is needed!

 Solution: The ASP.NET can generate such a description in the form of a

WSDL (Web Service Description Language) file.

 To obtain the WSDL file from ASP.NET, request the .asmx file

with ?WSDL attached to the URL.

 Alternatively, the developer can write the WSDL file first or obtain it

from a 3rd party to describe what the service should do, and use the

SDK utility program wsdl.exe to generate a template file.

 The client application developer will probably not deal with raw WSDL

files but rather use them through interpretive tools to develop client

application.

 The WSDL file also shows the supported protocols and how to access

the service via these protocols from the client application.

Building XML Web Service Clients

 ASP.NET funnels incoming requests to XML Web service

objects packaged in 3 different ways

 HTTP GET

 HTTP POST

 SOAP (Simple Object Access Protocol)

 SOAP is easier and more powerful than the other two methods.

1. A Web service client formats a SOAP request packet

2. The client sends the SOAP request to the XML Web service via an

HTTP POST operation.

3. The XML Web service parses the request, create the object, call

the method with the specified parameters, and return a SOAP

response to the Web service client.

Calling a Web Service via SOAP

 A client-side SOAP proxy class makes client

applications much easier to write

 The .NET Framework SDK provides wsdl.exe to

generate proxy class from the WSDL file for accessing

the methods in the specified language.

 Visual Studio .NET uses the proxy class generator

internally.

 Create a Windows Forms project

 Add the XML Web service page as a Web Reference to the

project. This will run wsdl.exe internally and ask for a SOAP-

based proxy in the language of the project.

 Visual Studio then displays the namespace of the proxy class

in Solution Explorer.

 To access the XML Web service from the client, simply create

an object of the proxy class and call the desired method on it.

Web Service Discovery

 This is the aspect of making the presence and capabilities of a

Web Service known to the world.

 This is the UDDI (Universal Discovery, Description, and

Integration) business registry service.

 Initiated by Ariba, IBM, and Microsoft. Supported by more than

130 companies.

 Provides a standard place to register Web Services. Check out

www.uddi.org.

 UDDI is a specification built on SOAP/XML and defines a

document format and protocol for searching and retrieving

discovery documents - which in turn link to DISCO documents.

 DISCO (Discovery of Web Services) is a Microsoft protocol for

retrieving the contracts for Web Services (WDSL documents).

Calling a Web Service via HTTP Get

 By requesting a Web Service URL from the IE Address

field, ASP.NET will respond with a neatly-formatted page

that describes the Web Service and it’s methods. This

page even provides a simple means to run the methods.

 This is not UDDI or DISCO. Just a nicely-formatted page

built from the metadata.

 You can get the WSDL by appending “?wsdl” to the URL.

 To call a method, append the method name and

parameters to the URL like this:

/MethodName?Parm=Value&NextParm=NextValue…

e.g.

http://localhost/timeservice/TimeServiceVB.asmx/GetTime?ShowSe

conds=FALSE

 Calling the service in this manner will result in a simple

XML response containing the return value.

Calling a Web Service via HTTP Post

 The WSDL describes the requirements for doing this.

 The Web Service expects that the incoming

parameter values be contained in FORM fields with

specific names. Therefore, the FORM has to contain

INPUT elements named according to the WSDL. The

ACTION attribute names the method:



 The response is an XML string.

Visual studio.NET

Visual Studio .NET

 Increased programming productivity

 Easier to write code: drag and drop Web App and

Services Development.

 Fully supports the .NET Framework

 Simplified development

 Multi-language support

 Improved debugging

 Unified IDE

 Powerful design tools

 Windows Forms, Web Forms

 XML and component designers

 Consistent set of tools across languages

Visual Studio.NET

 Integrated Development Environment

 Visual Basic.NET

 Many language enhancements

 Inheritance,Overloading, Free Threading

 Visual C++

 Integration with .NET Framework with managed extensions

(classes)

 C#

 New development language

 Based on C/C++ with Garbage Collection/Memory Management

 JUMP (Java User Migration Path) to .NET (1/25/01)





Visual J++ has been removed from the Visual Studio suite.

VS.NET Features

 Single IDE for all Languages

 Server Explorer

 Event Viewer, Message Queues, Services

 SQL Databases, Data Connection, Etc.

 Integrated IE Browser

 HTML/XML Editors

 Macros/Macro Explorer

 Solution Explorer

 Tabbed Documents

 Dynamic Help

 Common Forms Editor

 VB.NET, C++, and C#

Reference

1.http://www.microsoft.com

2.http://www.15seconds.com

3.http://asp.net

4.http://ado.net