Introduction to ASP related to basics of asp

Introduction to ASP related to basics

1. Chapter 1: An Introduction To
ASP.NET Web Programming
Liu, Jie
Professor
Department of Computer Science
Western Oregon University
[email protected]

2. Web Applications
The Client/Server model --a computation model for PCs to connect to
other computers, like the monitor and mainframe architecture model.
•Client –sends a request
Thin client
Thick client
•Server –answers the requests
For Web based applications
•Communication are through HTTP (hypertext Transfer Protocol)
What is a protocol
•Client is a browser such as IE (Internet Explorer)
•A browser displays pages defined using HTML tags (Hypertext, Markup
Language)
Static pages –not going to change
Dynamic pages –formed dynamically according to the requests
•The application itself is defined on a web server such as IIS (Internet
Information Services), with in turn may interact with other server such as a
Database Management System (DBMS) that is hosted on a database
server

3. Web Applications
Domain name
Path
http://sundown.wou.edu:81/en/mail.html?lang=en&laurel=on&cal=1
Protocol
Port
Page/file
Start of parameters
Parameter #1
Parameter #2

4. Dynamic Pages
A dynamic page is generated each time it is called
The same page may be posted back to the server for
processing.
Nevertheless, the page itself is stateless, i.e., it will not
maintain the value of a variable between each loading of
the page

5. More About State
“State” refers to the values of a variable or object
Variables in a web page is stateless meaning that
they do not “remember” their previous values
Methods used to maintain a variable’s state
include
•Use view state
•Use session or application state object
•Using static variable (C# feature)
•Use cookie
•Use database
(show Website 3 example and Visual Studio)

6. A Closer Look at the example
The .ASPX page
•Page directives
<%@ Page Language="C#" AutoEventWireup="true"
CodeFile="Default.aspx.cs" Inherits="_Default" %>
AutoEventWireupallows Page_Load linked with page load event and
called when the page is loaded
The .ASPX.CS page
using System.Web.UI.HtmlControls;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
… …
if (IsPostBack)
… …

7. A Closer Look at the example
More about the Visual Studio in coming chapters
A page and a page behind it (separation of
presentation and business logic)
Controls, properties, and events
If I change nTemp to be a static variable, what will
happen?
Different between design view and source view

8. The .Net Framework Structure
Remote users
over Internet
Any Browser
Remote Systems
Over Internet
Any Hardware/OS
Local users
Traditional Window
application
ASP.NET
Application Services
Web Forms Web Services
Windows Forms
Controls Windows Application Services
.Net Compliant Programming Languages **
VB.NET, C++, C#, J++, etc
.Net Framework Class Library
Common Language Runtime
Operating System
Windows 2000/2003/NT/98/ME/XP and may be other OSs
.Net Framework

9. VB, C#, and J++
//Declareandinitializeastring.string
strFruit= "oranges,apples,peaches,kumquats,nectarines,mangos";
//Declareanarray.
string[]arrFruit;
//Placeeachwordinanarrayelement.
arrFruit=strFruit.Split(new Char [] {',', '.', ':'});
//Sortthearray.
System.Array.Sort(arrFruit);
//Putthesortedarraybackinthestring.
strFruit=System.String.Join(" ",arrFruit);

10. Summary
Have general understanding about the following
•Web applications
•Web page
•Stateless
•ASP.NET components (IIS, frame work, CLR, etc)
•Client/Server
•Dynamic pages
•URL
Helpful web sites
•www.msdn.microsoft.com
•www.Asp.net