Transcript ASP.Net - Seattle Central College

ASP.NET
ASP AND .NET
.Net is a collection of libraries, templates and
services designed to make programming
applications of all kinds, easier, more flexible
(multi platform), and more scalable
 ASP.Net is a subset of .Net that contains tools
for developing web based applications

CLIENT/SERVER OVERVIEW
A server is a program that makes services
available to another program (a client)
 For instance, A web server such as IIS (Internet
Information Server) or Apache makes web
pages available to a client application such as
a browser
 A database server makes data available to
client that makes a valid request

CLIENT/SERVER OVERVIEW CONT.
ASP.Net pages are served from IIS when a
browser requests an .apsx page.
 IIS passes the request to .Net which processes
the C# or VB code and ASP controls, makes any
database requests and renders them into xhtml
 IIS then sends the rendered page to the
browser that made the request

ASP.NET SERVER/CLIENT
ELEMENTS OF AN ASP PAGE
The Page
 Web Form
 Html and ASP.Net Controls
 Code behind
 CSS

THE PAGE
The page is the container for everything else
 An ASP application can contain several pages
 Usually the starting page is called “Default.aspx”
 Every page begins with a directive

<%@ Page Language="C#" AutoEventWireup="true"
CodeFile="Default.aspx.cs" Inherits="_Default" %>

This directive tells IIS that the page is an ASP.Net
application
THE WEB FORM
An ASP. Page can have only 1 form.
 A key attribute of the form is runat=“server”
which tells IIS to send it to .Net for compiling
and rendering. (Plain html elements are just
passed through to the client without any .net
processing)
 All asp controls must be contained within the
form

HTML AND ASP CONTROLS

An ASP.Net page can use
 plain
xhtml
 Xhtml controls (xhtml with the runat=“server”
attribute added)
 ASP.Net controls, controls provided by .Net Library
 Client side JavaScript
DESIGN AND SOURCE VIEWS
ASP.net pages have two views Design and Source
 Design view shows controls approximately as they
will appear on the rendered page (some info
shown here won’t be displayed)
 Source view shows the html and the asp.net
controls.
 ASP controls are represented as XML fragments
 Controls can be added in Design or source views

XML FRAGMENT OF AN ASP CONTROL
<asp:Label ID="Label1" runat="server"
Text="Enter the Miles"></asp:Label>
CODE BEHIND
ASP.Net allows you to write the code in a
separate file.
 This makes code easier to read and maintain
 The page directive tells .Net where to find the
code page.
 Code can still be placed directly in the web
page if you wish either between <script> tags
or between <% %> brackets

CSS
ASP.Net supports CSS and has a good CSS
editor
 CSS classes and styles can be added to a ASP
control by using the CssClass attribute
<asp:TextBox ID="txtMiles" runat="server"
CssClass="entry"></asp:TextBox>

ASP PAGES AND STATE
ASP.Net, like all web pages are stateless.
 Every time you click and button or use control that
causes postback the page is re-rendered from the
server
 Information is not retained between postbacks
without some additional programming. (Windows
forms have state. They keep their variable values
and contents in RAM)
 This has several implications for web application
development that we will have to examine later
