Title: Chapter 1: An Introduction To ASP.NET Web Programming
1Chapter 1 An Introduction To ASP.NET Web
Programming
Professor Department of Computer Science
Western Oregon University Liuj_at_wou.edu
2Web 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
3Web Applications
http//sundown.wou.edu81/en/mail.html?langenlau
reloncal1
Port
Domain name
Page/file
Parameter 1
Protocol
Path
Start of parameters
Parameter 2
4Dynamic 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
5More 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 variables 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)
6A Closer Look at the example
- The .ASPX page
- Page directives
- lt_at_ Page Language"C" AutoEventWireup"true"
CodeFile"Default.aspx.cs" Inherits"_Default" gt - AutoEventWireup allows 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)
-
7A 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
8The .Net Framework Structure
Remote users over Internet Any Browser
Remote Systems Over Internet Any Hardware/OS
Local users Traditional Window application
.Net Framework
ASP.NET Application Services
Windows Forms Controls Windows Application
Services
Web Forms
Web 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
9VB, C, and J
- // Declare and initialize a string.stringÂ
- strFruit "oranges,apples,peaches,kumquats,nectar
ines,mangos" - // Declare an array.
- string arrFruit
- // Place each word in an array element.
- arrFruit  strFruit.Split(new Char ',', '.',
'') - // Sort the array.
- System.Array.Sort(arrFruit)
- // Put the sorted array back in the string.
- strFruit  System.String.Join(" ", arrFruit)
10Summary
- 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