Lecture #1 ASP.NET in Microsoft .NET Framework ASP Active ...students.cypresscollege.edu/cis225/lc01.pdf · ASP.Net – Penn Wu, PhD. 1 Lecture #1 ASP.NET in Microsoft .NET Framework

ASP.Net – Penn Wu, PhD. 1

Lecture #1 ASP.NET in Microsoft .NET Framework

Introduction ASP stands for Active Server Pages, while .Net simply means it is part of Microsoft’s .Net

Framework. Although it was developed by Microsoft, ASP.NET is an open source server-side

Web application framework designed for Web development to produce dynamic Web pages.

When an ASP.NET application runs, the server maintains information about the current

application, such as session, the current HTTP request, the requested page, and so on.

Programmers can thus use a combination of ASP.NET tools to build function-rich applications

to interact with the users and the client browsers. The Request object, for example, contains a

property named Browser that returns an object of type HttpBrowserCapabilities. This object

also provides properties such as browser, version, major version, and minor version such that

programmers can use to determine the client browser type. The following is a sample

ASP.NET code that can display information about the client browser.

<%@ Page Language="VB" %>

<script runat="server">

Sub Page_Load()

Dim str As String = ""

str &="<b>User Agent:</b>" & Request.UserAgent & "<br>"

str &="<b>Browser:</b>" & Request.Browser.Browser & "<br>"

str &="<b>Version:</b>" & Request.Browser.Version & "<br>"

str &="<b>Major:</b>" & Request.Browser.MajorVersion() & "<br>"

str &="<b>Minor:</b>" & Request.Browser.MinorVersion() & "<br>"

label1.Text = str

End Sub

</script>

<!DOCTYPE html>

<html>

<body>

<asp:Label id="label1" runat="server" />

</body>

</html>

The following is the C# version

<%@ Page Language="C#" %>


void Page_Load()

{

String str = ""

str += "<b>User Agent:</b>" + Request.UserAgent + "<br>";

str += "<b>Browser:</b>" + Request.Browser.Browser + "<br>";

str += "<b>Version:</b>" + Request.Browser.Version + "<br>";

str += "<b>Major:</b>" + Request.Browser.MajorVersion() +

"<br>";

str += "<b>Minor:</b>" + Request.Browser.MinorVersion() +

"<br>";

label1.Text = str;

}

</script>

.............


It is necessary to note that the curriculum guide for this class recommends that the

instructor use Visual Basic .Net as the primary language to write demo scripts for the rest

of this course’s lectures. The instructor, however, will provide C# version of the sample code

for those who are familiar with the C# language throughout this course. Students have the

options to use either VB .Net or C# to write ASP.NET programs to fulfil all course

requirements, including assignments, exams, all learning activities.

“Classic ASP”

script and

HTML

Prior to the integration with .NET Framework, ASP is Microsoft’s first server-side script

engine for dynamically generated web pages and was initially released as an add-on to Internet

Information Services (IIS) via the Windows NT 4.0 Option Pack in 1996. Throughout this

course, the instructor uses the term “class ASP” to describe the syntax to write ASP codes

before the integration of ASP and the .NET Framework in January 2002. Microsoft used to

define “classic ASP” as a development framework for building web pages and web sites with

HTML and CSS (cascading style sheet). A “classic ASP” script usually:

uses HTML tags to define the page layout

uses CSS to set the appearance of the page content

uses server-side ASP code, surrounded by the delimiters <% and %>, to dynamic generate

contents.

It is necessary to note that “classic ASP” is a server-side language that must run inside IIS

(Internet Information Services) servers. ASP codes will not run in a Windows machine unless

IIS server is present. Instructions about how to obtain a free version of IIS, known as IIS

Express, are available in a later section and the learning activities. The following is a very

simple “class ASP” file whose file name extension is “.asp” (e.g. “test.asp”). It is created

using “Notepad” (notepad.exe) which is a very generic text-editor included in all versions of

Microsoft Windows since Windows 1.0 in 1985. By the way, the instructor purposely uses

VBScript to write the following “classic ASP” script for the sake of demonstration. The code

will return the current date and time values. By the way, throughout this course, let the file

extension be “.aspx” to comply with the new naming convention of ASP.NET. A later section

will discuss the new naming convention.

<!Doctype html>

<html>

<body>

The server's current time:<br />

<%

Response.Write(Now())

%>

</body>

</html>

Unlike an .exe application, an ASP file is just a text file. An ASP file can contain text, HTML,

XML, and ASP scripts; however, only the ASP scripts are executed on the server. In the above

example, classic ASP scripts are enclosed by a pair of “<%” and “%>”. The rest of generic

HTML codes. When a browser requests an ASP file, IIS passes the request to the ASP engine

on the server. The ASP engine reads the file, line by line, and executes the scripts in the file.

Finally, the ASP file is returned to the client browser as plain HTML. The following is a

sample HTML content the above “classic APS” code will generate for the IIS server to send to

the client browser.

<!Doctype html> <html>

<body>

The server's current time:<br />

1/3/2015 11:47:04 AM

</body>

</html>


Server-side scripts can only be read, interpreted, and executed by web servers to produce

output; therefore, programmers must upload ASP files to an IIS server before an execution

request can be made. The client browser can request ASP script for execution; however, the

client browser does not and cannot have access to view the server-side script. It is necessary to

note that server scripts are executed on the server, only HTML outputs will be returned to the

client browser. During the HTTP-based communication, a client browser can only see and read

HTML tags, CSS, and the results of server-side script.

The following is a simple “classic” ASP script and its client-side result. ASP server-side script

can contain any expressions, statements, procedures, or operators. In this script, the instructor

declares a variable named “msg” using the dim keyword. The instructor then assigns a string,

"Welcome to ASP!", to the “msg” variable as value. The response.write() method is a

generic ASP method that writes output to a client browser. The client browser only receives the

output produce by the response.write() method.

Server-side script Client-side result <!DOCTYPE html>

<html>

<style>

p { background-color: red }

</style>

<body>

<p>

<%

dim msg

msg = "Welcome to ASP!"

response.write(msg)

%>

</p>

</body>

</html>

<!DOCTYPE html>

<html>

<style>

p { background-color: red }

</style>

<body>

<p>

Welcome to ASP!

</p>

</body>

</html>

HTML is the de facto language for creating web pages. ASP codes are typically embedded in

an HTML page, even if the file extension is .apsx or .asp. It is necessary to have a basic

understanding of HTML elements. HTML uses angle brackets to indicate how your content

should be rendered (or displayed) in the browser. The angle brackets are referred to as tags; a

pair of tags holding some text is referred to as an element. The following is a very simple

HTML code. The <!DOCTYPE html> declaration is a statement that declares to the web

browser about what version of HTML the page is written in. This course adopts HTML5.

<!Doctype html>

<html>

<body>

<h1>Hello World!</h1>

<p>I am learning ASP.NET.</p>

</body>

</html>

IIS

Server

ASP

Programmers

Client

Browser

Upload ASP

scripts

Request execution

Of ASP scripts

Return

HTML outputs


An HTML element must start with a greater than (<) followed by the name of element and ends

with less than sign (>). The “<html>” and “</html>” tags make a pair that encloses all the

HTML contents. The “<html>” tag is said to be the opening tag and “</html>” is the closing

tag. The closing tag always requires a forward slash (/). The “<body>” and “</body>” tags

define a section that contains all the contents of an HTML document, such as text, hyperlinks,

images, tables, lists, etc. The <h1> element, with an opening tag (<h1>) and a closing tag

(</h1>), is used to signify a heading at level one. The <p> tag defines a paragraph. Basically

ASP is a development framework for building dynamic web pages and web sites with HTML.

The following is a list HTML elements frequently used throughout this course. The table is

provided by Imar Spaanjaars, the author of a good reference book: Beginning ASP.NET 3.5:

In C# and VB (ISBN: 978-0-470-18759-3).

Tag Description Example

<html> Used to denote the start and end

of the entire page. <head><title>

<head>

<title>

Used to denote a special section

of the page that contains data

about the page, including its

title.

<head> <title>Welcome to my

site</title></head>

<body> Used to denote the start and end

of the body of the page.

<body> Page body goes

here</body>

<a> Used to link one web page to

another.

<a href="http://www.att.com">

AT&T site</a>

<img> Used to embed images in a

page. <img src="logo.gif" />

<b> <i>

<u>

Used to format text in a bold,

italic, or underline font.

This is <b>bold text</b> while

<i>this text is in italic</i>

<form>

<textarea>

<select>

<input>

Used for input forms that allow

users of a web site to submit

information to the server.

<input type="text" value="Some

Text" />

<table>

<tr>

<td>

These tags are used to create a

layout with a table. The <table>

tag defines the entire table,

while the <tr> and <td> are

used to define rows and cells,

respectively.

<table><tr> <td>This is a Cell

in Column 1</td> <td>This is a

Cell in Column

2</td></tr></table>

<ul>

<ol>

<li>

These three tags are used to

create numbered or bulleted

lists. The <ul> and the <ol>

define the looks of the list

(either unordered, with a simple

bullet, or ordered, with a

number), while the <li> is used

to represent items in the list.

<ul> <li>First item with a

bullet</li> <li>Second item

with a bullet</li></ul><ol>

<li>First item with a

number</li> <li>Second item

with a number</li></ol>

<span>

This tag is used to wrap and

influence other parts of the

document. It appears as inline,

so it adds no additional line

break to the page.

<p>This is some normal text

while <span style="color:

red;">this text appears in

red</span></p>

<div>

Just like the <span> tag, the

<div> is used as a container for

other elements. However, the

<div> acts as a block element,

which causes an explicit line

<div>This is some text on 1

line</div><div>This text is put

directly under the previous

text on a new line. </div>


break after the <div> tag by

default.

There is a shorthand way for displaying text in ASP.NET which does not use the

response.write() method, instead, it uses the “=” sign. The following two “classic ASP”

scripts produce exactly the same output. The IIS server reads and interprets the script, <%

response.write("Welcome to ASP!") %>, and produces the output -- Welcome to

ASP!. The IIS server also knows that the “=” technically equals to the “response.write()”

method.

<% response.write() %> <%= %> <!DOCTYPE html>

<html>

<body>

<%

response.write("Hello World!")

%>

</body>

</html>

<!DOCTYPE html>

<html>

<body>

<%="Hello World!" %>

</body>

</html>

In the above sample code, the instructor also use CSS to define the background color of the

<p> elements. Cascading Style Sheets (CSS) is a style sheet language used for describing the

look and formatting of a document written in a markup language. A CSS declaration always

ends with a semicolon, and declaration groups are surrounded by curly braces:

p { color:red; text-align:center; }

Accessing

.NET

Framework

tools from

class ASP

scripts

The .NET Framework is a software framework developed by Microsoft that runs primarily on

Microsoft Windows operating systems. It is also described as a programming infrastructure

created by Microsoft for building, deploying, and running applications and services that use

.NET technologies, such as desktop applications and Web services.

Interestingly, “classic ASP” scripts have the scalability to use certain properties and methods

provided by the .NET Framework. This is possibly because ASP codes must be executed and

interpreted by IIS server. Since all IIS servers must running in Windows operating systems,

ASP codes can use properties and methods provided by the .NET Framework. The Math class

is part of the .NET Framework which provides constants and static methods for trigonometric,

logarithmic, and other common mathematical functions. The sin() method of the Math class

can return the sine of the specified angle. The following script, which must be executed at an

IIS server (or an IIS Express server), demonstrates how a classic ASP code uses the sin()

method of the Math class. By the way, let the file name be something similar to “test.aspx”.

<!Doctype html>

<html><body>

<%= Math.sin(100) %>

</body></html>

The output is:

-0.506365641109759

The following is another example that demonstrates how to retrieve the value of the PI

property.

<!Doctype html>

<html><body>


<%= Math.PI %>

</body></html>

Interestingly, between “<%=” and “%>” of the following example, there is a very generic .NET

Framework statement which use the “Now” property of the “DateTime” struct to retrieve the

current date and time values from the operating system that runs IIS Express.

<!Doctype html>

<html><body>

<h1>Hello Web Pages</h1>

<p>The time is <%= DateTime.Now %></p>

</body></html>

A sample output is:

The following is another example that does not declare the language. It uses the

ToLongTimeString() method which is another .NET Framework method of the “DateTime”

struct to set the format of the output.

<!Doctype html>

<html><body>


<p>The time is <%= DateTime.Now.ToLongTimeString() %></p>

</body></html>

The above classic ASP scripts only use simple and generic tools provided by the .NET

Framework; therefore, any IIS server can understand it and execute it. However, most tools

provided by .NET Framework are designed to work with Visual C#, Visual Basic .NET, and

Visual C++. Without a .NET compliant language, such as C# or Visual Basic, it is difficult to

implement most tools provided by the .NET Framework, particularly tools that are created

using object-oriented paradigm and those that supports the Common Language Runtime

(CLR).

The rise of

ASP.NET

ASP.NET is the latest version of Microsoft’s Active Server Pages technology. Microsoft said

they re-designed ASP.NET based on the Common Language Runtime (CLR) to allow

programmers to write ASP.NET code using any supported .NET language. Unlike “classic

ASP”, ASP.NET is “a unified Web development model that includes the services necessary for

you to build enterprise-class Web applications with a minimum of coding…..,” because

Microsoft includes ASP.NET to its Microsoft .NET framework to make ASP.NET a powerful

tool for creating dynamic and interactive web pages. In other words, ASP.NET is now part of

the .NET Framework. When coding ASP.NET applications, programmers have access to

classes in the .NET Framework to use all methods, properties, and classes provided by the

.NET Framework. Programmers can code Web applications in any language compatible with

the common language runtime (CLR), including Microsoft Visual Basic and C#. These

languages enable you to develop ASP.NET applications that benefit from the common

language runtime, type safety, inheritance, and so on. The following figure illustrates the

languages Microsoft uses in the architecture of .NET Framework.

Figure. Visual Studio.NET

VB C++ C# Jscript JavaScript


Common Language Specification

ASP.NET Web Servers and

Web Forms

Windows Forms

ADO.NET: Data and XML

Base Classes

Common Language Runtime

This is a bottom-to-top architecture, meaning that the lower layers support upper layers.

ASP.NET is in a layer below the language layer. Microsoft meant to design the architecture in

such a way that ASP.NET can work with any of the .NET compatible language such as

VB.NET, C#, Managed C++ or Jscript.NET.

“Class ASP” file uses “.asp” for file extensions. An ASP.NET file also has meaningful file

extension, “.aspx”, “.ascx”, or “.asmx”. The “.aspx” extension implies that the files contain

static (X)HTML markup. The following table illustrates the meaning of file extensions used by

ASP.NET.

Table: Common ASP.NET File Extensions.

Extension Description

.aspx ASP.NET page file

.ascx ASP.NET User Control file (to be discussed in a later lecture)

.asmx Web Service file

.aspx.vb Visual Basic .NET code file for an ASP.NET page

.aspx.cs C# code file for an ASP.NET page

.sln Visual Studio .NET Solution file (not used in this course)

Throughout this course, the instructor chooses to use “.aspx” as file extension for all demo

scripts. The following is the naming convention where n is the number of lecture note and m is

the number of learning activity.

labn_m.aspx

Structure of an

ASP.NET file

An ASP.NET page is a text file consisting of structural elements. Each structural element can

perform one or more specific tasks. The output of one structural element could be used as input

of another. Typically, a dynamic ASP.NET web page might consists of four types of structural

elements: page directive, code declaration block(s), code rendering block(s), and HTML

block(s) (which may include CSS codes). The HTML block is optional; however, programmers

frequently use HTML code to define the page layout and content formats.

The following is an example that demonstrates what structural element are and how they work

in a generic ASP.NET file. By the way, its code is written in Visual Basic .NET. In VB.NET,

the combined “&=” is the concatenation operator which can append string to another string,

while the addition sign (&) is used to combine two values to make a new string. A later lecture

will discuss how to use the for loop in details.


Page directive

<script runat="server"> Code declaration

block Sub Page_Load()

For i As Integer = 1 To 6

label1.Text &= "<h" & i & ">Hi!</h" & i & ">"

Next

End Sub

Code Render block

using VB.NET codes


</script> End of code

declaration

<!Doctype html>

<html>

<body>

HTML block

<asp:Label id="label1" runat="server" /> Code render block

</body>

</html>

The output of the above code looks:

The following is the C# version.



void Page_Load()

{

for (int i=1; i<=6; i++)

{

label1.Text += "<h" + i + ">Hi!</h" + i + ">";

}

}

</script>

Both “page directive” and “code declaration block” are “declarative,” which means they are

used to specify certain characteristics (e.g. cache enabled) and properties (e.g. language) of the

ASP.NET page. Both “code rendering block” and “HTML block” and are “descriptive”, which

means they are used to describe how the output should be generated and how they should look

like.

All ASP.NET script start with one page directive, which specifies how the page should be

processed. Typically, page directives are placed at the very beginning of an ASP.NET file.

Next to “<%”, page directives start with the “@” symbol, followed by attribute/value pairs, and

ends with “%>”. The following table lists directives supported by ASP.NET’s Web Forms page

framework.

Directive Description @ Page Defines page-specific attributes used by the ASP.NET page parser

and compiler. Can be included only in .aspx files. @ Control Defines control-specific attributes used by the ASP.NET page parser

and compiler. Can be included only in .ascx files (user controls). @ Import Explicitly imports a namespace into a page or user control. @ Implements Declaratively indicates that a page or user control implements a

specified .NET Framework interface.


@ Register Associates aliases with namespaces and class names, thereby

allowing user controls and custom server controls to be rendered

when included in a requested page or user control. @ Assembly Declaratively links an assembly to the current page or user control. @ OutputCache Declaratively controls the output caching policies of a page or user

control. @ Reference Declaratively links a page or user control to the current page or user

control.

The following illustrates how to specify the chosen language, where lang must be one of the

compliant language such as “VB” or “C#”. ASP.NET treats any directive block (<%@ %>)

that does not contain an explicit directive name as an @ Page directive for a page. Other

declarations will be discussed in later lectures whenever they are used. If no language is

specified in the directive, the default is “VB”, or the default language specified in the

application’s Web.config file.

<%@ Page Language="lang" %>

IIS servers will rigidly abide by language declaration. The following example specifies that the

inline ASP.NET code in the page must be written in VB.NET.


In the following example, the instructor declares the page language to be “VB”, yet the

instructor also purposely uses C# to write a for loop to confuse the interpreter. By the way, the

following ASP.NET file contains both “page directive” and “code rendering block”, yet it does

not have “code declaration block”. In C#, the combined “+=” is the concatenation operator

which can append string to another string, while the addition sign (+) is used to combine two

values to make a new string.

<% @Page language="VB"%>

<script runat="server" language="C#">

void Page_Load()

{

for (int i=1; i<6; i++)

{

label1.Text += "<h" + i + ">Hi</h" + i + ">";

}

}

</script>

<!Doctype html>

<html><body>


</body></html>

The server simply returns the following error message, which evidentially shows that the server

is using “VB” syntax to investigate the code due to the page declaration.

Parser Error Message: Cannot use 'C#' because another language

has been specified earlier in this page (or was implied from a

CodeFile attribute).

The following is the correct C# version. The page declaration specifies that the ASP.NET script

should be executed using C# language.

<% @Page language="C#"%>



void Page_Load()

{

for (int i=1; i<6; i++)

{

label1.Text += "<h" + i + ">Hi</h" + i + ">";

}

}

</script>

<!Doctype html>

<html><body>


</body></html>

The following demonstrates how to use the Import directive to the System.Globalization

namespace and then use the CultureInfo class to specify a specific culture. In the

CreateSpecificCulture() method, the instructor uses "he-IL" to specify a CultureInfo that

means “Hebrew”.


<%@ Import Namespace="System.Globalization" %>


Sub Page_Load()

Dim culture As CultureInfo =

CultureInfo.CreateSpecificCulture("he-IL")

End Sub

</script>

A Code Declaration Block defines a section of server code that are embedded in ASP.NET

application files within <script> blocks marked with a runat="server" attribute. The

following illustrates its general syntax.

<script runat="server" language="lang" Src="path">

Code...........

</script>

lang: Specifies the language used in this code declaration block. If no language is

specified, this value defaults to that specified in the @ Page. However, the language must

comply with the one specified in the page directive.

Src: Specifies the path and file name of an external script file to load. When this attribute is

used, any other code in the declaration block is ignored. For example: <script

runat="server" src="test.cs" />.

The following is an example demonstrates how to load a long VB.NET code from an individual

file named “areacode.vb”.



Sub button1_Click(sender As Object, e As EventArgs)

label1.Text = findAreaCode(textBox1.Text)

End Sub

</script>

<script runat="server" Src="areacode.vb"></script>

<!Doctype html>

<html>


<body>

<form id="form1" runat="server">

<asp:TextBox id="textBox1" runat="server" />

<asp:Button id="button1" runat="server" Text="Check"

OnClick="button1_Click" />

</form>

<p><asp:Label id="label1" runat="server" />

</body>

</html>




void button1_Click(Object sender, EventArgs e)

{

label1.Text = findAreaCode(textBox1.Text);

}

</script>

<script runat="server" Src="areacode.cs"></script>

<!Doctype html>

<html>

<body>



<asp:Button id="button1" runat="server" Text="Check"

OnClick="button1_Click" />

</form>


</body>

</html>

The following is a sample code that only contains a “code declaration block” in its ASP.NET

part of code. The instructor purposely omits the page declaration. Since the page directive is

not in use, the instructor places “language declaration” inside the <script> tag. By the way,

the following code produces the same results as the above one.

<script runat="server" language="VB">

Sub Page_Load()


label1.Text &= "<h" & i & ">Hi!</h" & i & ">"

Next

End Sub

</script>

<!Doctype html>

<html><body>


</body></html>

The above code also demonstrates what “on demand” means. The for loop is placed within a

subroutine named “Page_Load” which is defined by “Sub” and “End Sub”. According to the

“event model” of .NET Framework, the Load event is raised when an ASP.NET page is

launched. In the above code, the instructor creates the Page_Load() method as event handler of


the Load event. In other words, the Page_Load() subroutine is tied to the Load event. Since the

Load event is raised when the ASP.NET file is launched, IIS server will automatically call the

Page_Load() subroutine every time when the ASP.NET page is loaded. In the above example,

the for loop defined in the “Page_Load” subroutine repeatedly inserts a string “Hi!” to

ASP.NET’s <asp:Label> control which has an ID “label1”. ASP.NET controls are ASP.NET

tools provided by the .NET Framework to be used on ASP.NET Web pages. They are called for

execution on a "on-demand" basis, such as when the page is loaded or a button is clicked, to

render HTML markup to be sent to a client browser. Many Web server controls resemble

familiar HTML elements, such as buttons and text boxes. Other controls encompass complex

behavior, such as a calendar controls, and controls that manage data connections. Later lectures

will discuss ASP.NET controls in details.

The following is the C# version of the above code. Yet, the instructor purposely demonstrates

the use of “Response.Write” method (which is a method of “classic ASP”) in an ASP.NET file

to show the “downward compatibility” of ASP.NET. The protected access modifier specifies

that one or more declared programming elements are accessible only from within their own

class or from a derived class. By the way, the private access modifier to specify that one or

more declared programming elements are accessible only from within their declaration context,

including from within any contained types. If the access modifier is omitted, it is default to

public. The public access modifier can specify that one or more declared programming

elements have no access restrictions.

<!Doctype html>

<html>

<body>

<script runat="server" language="C#">

protected void Page_Load()

{

for (int i=1; i<6; i++)

{

Response.Write("<h" + i + ">Hi</h" + i + ">");

}

}

</script>

</body>

</html>

In the following example (written in Visual Basic .NET), the If..Then statement is a decisive

structure that makes decisions. It will take a language-specific interpreter to understand the

language-specific structure because every language has its own syntax and statement pattern.

Since the following If..Then statement was written in Visual Basic structure, it is necessary

to specify the language by place a language declaration: <%@ Page Language="VB" %>.


<!Doctype html>

<html><body>


<p>It is

<%

If DateTime.Now.Hour > 12 Then

Response.Write("afternoon")

End If

%>.

</p>

</body></html>


The following is the C# version of the above code. The language declaration statement is: <%@ Page Language="C#" %>.


<!Doctype html>

<html><body>


<p>It is

<%

if (DateTime.Now.Hour > 12)

{

Response.Write("afternoon");

}

%>.

</p>

</body></html>

Apparently how ASP.NET is interpreted and executed completely depends on how the

programmer declares the language, not how the server that hosts the code was configured. In

this class, you will soon find out most of the ASP.NET file are a combination of ASP.NET

code and Visual Basic .NET code.

ASP.NET Page

Life Cycle

Overview

Unlike class ASP, when an ASP.NET page runs, the page goes through a life cycle in which it

performs a series of processing steps. These include initialization, instantiating controls,

restoring and maintaining state, running event handler code, and rendering. In general terms,

the page goes through the stages outlined in the following table.

Stage Description Start In the start stage, the page determines whether the request is a

“postback” or a new request.

Initialization During page initialization, controls on the page are activated to accept

and process data. However, if the current request is a postback, the

postback data has not yet been loaded and control property values have

not been restored to the values from view state.

Load During load, if the current request is a postback, control properties are

loaded with information recovered from view state and control state.

Postback event

handling If the request is a postback, control event handlers are called. After

that, the Validate method of all validator controls is called, which sets

the IsValid property of individual validator controls and of the page.

Rendering During the rendering stage, the page calls the Render method for each

control, providing a text writer that writes its output to the

OutputStream object of the page's Response property. Unload The Unload event is raised after the page has been fully rendered, sent

to the client, and is ready to be discarded.

Unlike class ASP, ASP.NET pages requires “automatic event wire-up”, meaning that ASP.NET

looks for methods with particular names and automatically runs those methods when certain

events are raised. If the AutoEventWireup attribute of the @ Page directive is set to true, page

events are automatically bound to methods that use the naming convention of Page_event, such

as Page_Load() and Page_Init(). In the following example, when a page loads ASP.NET will

automatically call the subroutine Page_Load() to display the current local date/time values.




Sub Page_Load()

label1.Text = "Local time is " & DateTime.Now

End Sub

</script>

<!Doctype html>

<html><body>


</body></html>




void Page_Load()

{

label1.Text = "Local time is " + DateTime.Now;

}

</script>

The Page_Load() method is the basic “automatic event wire-up.” When the Load event is

raised, the Page object calls the Page_Load() method on the Page automatically, and then

recursively does the same for each child control until the page and all controls are loaded.

The term “postback” refers to an HTTP value that is given by a client browser to the same

page as a response to a control. In the following script, the user is asked to select from one of

the time zones (local or UTC). The selected value is the “postback” that would be passed to the

server in order to decide which set of date/time values to display. ASP.NET uses the

Page.IsPostBack property for the programmers to get a value that indicates whether the page is

being rendered for the first time or is being loaded in response to a postback. The following is a

sample code that uses the Page_Load() method to display the local date/time values. It will also

display a button asking if the user prefers using the UTC time zone. By clicking the button, the

user send a postback request to the same page, the value of IsPostBack is thus set to False. By

the way, a later lecture will discuss how to create HTML server controls in details.



Sub Page_Load()

If Not IsPostBack Then


ShowFrom()

Else

label1.Text = "UTC time is " & DateTime.UtcNow

End If

End Sub

Sub ShowFrom()

Dim form1 As New HtmlForm()

form1.ID = "Form1"

form1.Method = "post"

Dim button1 As New Button()

button1.Text = "Use UTM Time Zone"

form1.Controls.Add(button1)

Controls.Add(form1)


ENd Sub

</script>

<!Doctype html>

<html><body>

<asp:PlaceHolder id="placeHolder1" runat="server" />

<p><asp:Label id="label1" runat="server" /></p>

</body></html>




void Page_Load()

{

if (!IsPostBack)

{


ShowFrom();

}

else

{

label1.Text = "UTC time is " + DateTime.UtcNow;

}

}

void ShowFrom()

{

HtmlForm form1 = new HtmlForm();

form1.ID = "Form1";

form1.Method = "post";

Button button1 = new Button();

button1.Text = "Use UTM Time Zone";

form1.Controls.Add(button1);

Controls.Add(form1);

}

</script>

<!Doctype html>

<html><body>



</body></html>

Installing IIS

Express

All the demo scripts as well as codes of learning activities provided throughout this course

require Microsoft’s IIS (Internet Information Server) server. However, not every student has

the luxury to run IIS on her/his Windows operating systems. One alternative is to use the IIS

Express which is a lightweight, self-contained version of IIS optimized for developers. IIS

Express makes it easy to use the most current version of IIS to develop and test IIS-based

websites.

Although the word “Express” implies that it is “not a full version” of IIS server, IIS Express

provides every needed feature to learning ASP.net programming. According to Microsoft, IIS

Express has all the core capabilities of IIS sever with the following features designed to

facilitate the learning of ASP.NET website development:

It does not run as a service or require administrator user rights to perform most tasks.

Multiple users of IIS Express can work independently on the same computer.


As of January 2016, the latest version of IIS Express is 10.0. Students of this course can install

IIS 10.0 Express through the Microsoft Download Center. The URL is:

https://www.microsoft.com/en-us/download/details.aspx?id=48264. Depending

on the version of Windows operating systems, there are two versions of IIS Express .msi file,

as distinguished below.

OS File Name 32-bit iisexpress_x86_en-US.msi

64-bit iisexpress_x64_en-US.msi

Upon completing the installation, students can immediately launch the IIS Express from a

Windows Command Prompt (cmd.exe). They do not need Administrator user rights to develop,

test, and debug ASP.NET script with IIS Express. The default host name is

http://localhost which uses the local loopback IP address: http://127.0.0.1. The

default port is 8080. However, they must have Administrator user rights if you want to run IIS

Express on ports numbered 1024 or less.

In an opened Command Prompt of a 32-bit OS with a sample prompt of

“C:\Users\D99324192”, programmer can type cd \Program Files\IIS Express and then

press [Enter] to navigate to the IIS Express directory.

C:\Users\D99324192>cd \Program Files\IIS Express

In a 64-bit OS, the command is cd \Program Files (x86)\IIS Express instead, as

shown below.

C:\Users\D99324192>cd \Program Files (x86)\IIS Express

In the “IIS Express” directory, type iisexpress and press [Enter] to launch the IIS Express,

as shown below:

C:\Program Files\IIS Express>iisexpress

The following message appears if the server is up and running. The IIS Express server will

create a default website named “WebSite1”. The following message also indicates the default

port number (e.g. 8080) the server is designate to use for HTTP connection.

Starting IIS Express ...

Successfully registered URL "http://localhost:8080/" for site

"WebSite1" application "/"

Registration completed for site "WebSite1"

IIS Express is running.

Enter 'Q' to stop IIS Express

Advanced

Configuration

Throughout this entire course, the above is what students need to install and configure in order

to launch and operate the IIS Express server. The following is a few “advanced” skills about

usage of the “iisexpress” command.

Type iisexpress /? and press [Enter] to view the IIS Express usage string. The output

looks:

IIS Express Usage:

------------------

iisexpress [/config:config-file] [/site:site-name]

[/siteid:site-id] [/systray:boolean]

iisexpress /path:app-path [/port:port-number] [/clr:clr-version]

[/systray:boolean]


/config:config-file

The full path to the applicationhost.config file. The default

value is the IISExpress8\config\applicationhost.config file that

is located in the user's Documents folder.

/site:site-name

The name of the site to launch, as described in the

applicationhost.config file.

..............

..............

iisexpress /path:c:\myapp\ /port:80

This command runs the site from c:\myapp folder over port 80.

IIS Express and IIS use the ApplicationHost.config file, which specifies global settings for

sites, application pools, handlers, etc. IIS Express uses a default, user-specific

ApplicationHost.config file to allow many users to share the same computer without

interfering with other user’s settings. This file is located in the

%username%\Documents\IISExpress\config folder (where “%username%” is the

programmer’s actual user name such as “D99324192”) or %username%\My

Documents\IISExpress\config folder, depending on the generation of Microsoft’s

Windows OS.

Those who wish to run ASP.NET scripts from a specific website such as “Website2” by

default can modify the following statement in the ApplicationHost.config configuration

file.

iisexpress /site:WebSite2

Review

Questions

1. Which is the classic ASP code that can return the current date and time values?

A. <% Response.Display(Now()) %>

B. <% Response.Write(Now()) %>

C. <% Response.Show(Now()) %>

D. <% Response.Return(Now()) %>

2. Which can produce exactly the same result as the following code segment?

<%="Hello World!" %>

A. <% Response.Display("Hello World!") %>

B. <% Response.Write("Hello World!") %>

C. <% Response.Show("Hello World!") %>

D. <% Response.Return("Hello World!") %>

3. Which is the correct file extension for either Visual Basic.NET code or Visual C# code to be

incorporated in an ASP.NET Web page?

A. .aspx

B. ascx

C. .ascx.vb

D. .asvb.cs

4. Which is an example of the page directive used in ASP.NET?

A. <@?ASP Page Language="VB" />

B. <?ASP Page Language="VB" >

C. <%@ Page Language="VB" %>

D. <%@ Page Language="VB" />


5. Given the following code segment, which part specifies that the code must be executed by

server?


ASP.NET code........

</script>

A. <script>

B. runat="server"

C. language="VB"

D. All of the above

6. Given the following code segment, which part is optional if you have declared it in the page

directive section?


ASP.NET code........

</script>

A. <script>

B. runat="server"

C. language="VB"

D. All of the above

7. Which is the class ASP ode to display "Hello world!"?

A. <% MessageBox.Show("Hello World") %>

B. <% Document.Write("Hello World") %>

C. <% Response.Show("Hello World") %>

D. <%="Hello World" %>

8. Which of the following specifies that one or more declared programming elements are

accessible only from within their own class or from a derived class? C# version of answers are

enclosed by [].

A. protected sub Page_load() [protected void Page_Load() { }]

B. private sub Page_load() [private void Page_Load() { }]

C. public sub Page_load() [public void Page_Load() { }]

D. partial sub Page_load() [partial void Page_Load() { }]

9. Given the following code, which is the identifier of the <asp:Label> control?

<asp:Label id="label1" Text="msg" Value="Show" runat="server" />

A. Label

B. label1

C. msg

D. Show

10. Which can declare a subroutine that is automatically tied to the Load event such that the

subroutine will be launched automatically? C# version of answers are enclosed by [].

A. Sub Page_Load()...End Sub [void Page_Load() { }]

B. Sub Page_Start()...End Sub [void Page_Start() { }]

C. Sub Page_Begin()...End Sub [void Page_Begin() { }]

D. Sub Page_Launch()...End Sub [void Page_Launch() { }]


Lab #1 ASP.NET in Microsoft .NET Framework

Preparation #1: Installing IIS 10.0 Express

1. To find out if your computer is running a 32-bit or 64-bit version of Windows in Windows 7/Vista, open

System by clicking the Start button , right-clicking Computer, and then clicking Properties. Under

System, you can view the system type. Record your OS type: ____________________________.

2. Use a web browser to go to https://www.microsoft.com/en-us/download/details.aspx?id=48264

to download the Internet Information Services (IIS) 10.0 Express. There are two different versions: 32 bit and

64 bit. Be sure to scroll up and down to find the correct version of file and then download it.

OS Sample file name



3. Launch the installation. You need to accept the license agreement, and then click Install.

4. Wait till the installation completes. Click Finish.


5. To launch IIS 10.0 Express, go to the “X:\Program Files\IIS Express” directory (X is the drive name and is

typically “C”) using Windows Explorer. Find the “iisexpress.exe” file and double click it. Note: You can

consider creating a shortcut on the Windows desktop for “iisexpress.exe” because you will need to launch it

every time before you can test ASP.NET scripts.

6. A Command Prompt window will pop up with the following message. Do not close this window. You need to

keep it running. Be sure to write the URL and its port number (e.g. http://localhost:808).

Starting IIS Express ...

Successfully registered URL "http://localhost:8080/" for site

"WebSite1" application "/"

Registration completed for site "WebSite1"

IIS Express is running.

Enter 'Q' to stop IIS Express

7. Use a web browser to go to http://localhost:8080/ (use the correct one if your is different from

example), and you should now see the following.

8. Use Windows Explorer to go to the “X:\Users\%USERNAME%\My Documents\My Web Sites\WebSite1”

directory (which will be the default directory for testing all ASP.NET scripts in this semester), use Notepad to

create a new text file named “lab0.aspx“ with only one of the following versions of code: Visual Basics and C#.



Sub Page_Load()

label1.Text = "Welcome to ASP.NET!!<br>" & DateTime.Now

End Sub

</script>

<!DOCTYPE html>

<html><body>


</body></html>

Or




void Page_Load()

{

label1.Text = "Welcome to ASP.NET!!<br>" +

DateTime.Now;

}

</script>

<!DOCTYPE html>

<html><body>


</body></html>

9. Double check to make sure the lab0.apsx file is saved to the “WebSite1” directory. The file path must be:

“X:\Users\%USERNAME%\My Documents\My Web Sites\WebSite1\lab0.aspx”

10. Use a web browser to go to http://localhost:8080/lab0.aspx. If you see something similar to the

following, you are ready to cruise through this course.

Learning Activity #1: Testing a simple ASP.NET script locally (with IIS installed)

(Note: Be sure to complete Preparation #1 before you move on to the next step.)

1. Use Notepad to create a new file X:\Users\%USERNAME%\My Documents\My Web

Sites\WebSite1\lab1_1.aspx with only one of the following versions of code: Visual Basics and C#.



Sub Page_Load()

Dim str As String = ""

str & = "<b>User Agent:</b> " & Request.UserAgent & "<br>"

str & = "<b>Browser:</b> " & Request.Browser.Browser & "<br>"

str & = "<b>Version:</b> " & Request.Browser.Version & "<br>"

str & = "<b>Major:</b> " & Request.Browser.MajorVersion & "<br>"

str & = "<b>Minor:</b> " & Request.Browser.MinorVersion & "<br>"

label1.Text = str

End Sub

</script>

<!DOCTYPE html>

<html>


<body>


</body>

</html>

Or



void Page_Load()

{

String str = "";

str += "<b>User Agent:</b> " + Request.UserAgent + "<br>";

str += "<b>Browser:</b> " + Request.Browser.Browser + "<br>";

str += "<b>Version:</b> " + Request.Browser.Version + "<br>";

str += "<b>Major:</b> " + Request.Browser.MajorVersion + "<br>";

str += "<b>Minor:</b> " + Request.Browser.MinorVersion + "<br>";

label1.Text = str;

}

</script>

<!DOCTYPE html>

<html>

<body>


</body>

</html>

2. Use a web browser to access http://localhost:8080/lab1_1.aspx, you should now see:

3. Download the “assignment template”, and rename it to lab1.doc if necessary. Capture a screen shot similar to

the above and paste it to a Microsoft Word document named “lab1.doc” (or .docx).

Learning Activity #2:





Sub Page_Load()



End Sub

</script>

<!DOCTYPE html>

<html>

<body>


<asp:Label id="label1" runat="server" Font-Size=14 />

<p><asp:Label id="label2" runat="server" Font-Size=14 ForeColor="Red">

</asp:Label></p>

</body>

</html>

Or



void Page_Load()

{



}

</script>

<!DOCTYPE html>

<html>

<body>

<asp:Label id="label1" runat="server" Font-Size=14 />

<p><asp:Label id="label2" runat="server" Font-Size=14 ForeColor="Red">

</asp:Label></p>

</body>

</html>


3. Capture a screen shot similar to the above and paste it to a Microsoft Word document named “lab1.doc” (or

.docx).






Sub Page_Load()

Dim str1 As String = ""

Dim str2 As String = ""


str1 &= "<h" & i & ">Hi!</h" & i & ">"

str2 &= "<h" & (7-i) & ">ASP.NET!</h" & (7-i) & ">"

Next


label1.Text = str1

label2.Text = str2

End Sub

</script>

<!Doctype html>

<html>

<body>

<table><tr>

<td>


</td>

<td>


</td>

</tr></table>

</body>

</html>

Or



void Page_Load()

{

String str1 = "";

String str2 = "";

for (int i=1; i<=6; i++)

{

str1 += "<h" + i + ">Hi!</h" + i + ">";

str2 += "<h" + (7-i) + ">ASP.NET!</h" + (7-i) + ">";

}

label1.Text = str1;

label2.Text = str2;

}

</script>

<!Doctype html>

<html>

<body>

<table><tr>

<td>


</td>

<td>


</td>

</tr></table>

</body>

</html>




.docx).


1. Download the areacode.zip and extract both areacode.vb and areacode.cs files to the

“X:\Users\%USERNAME%\My Documents\My Web Sites\WebSite1” directory.





Sub button1_Click(sender As Object, e As EventArgs)

label1.Text = findAreaCode(textBox1.Text)

End Sub

</script>

<script runat="server" Src="areacode.vb"></script>

<!Doctype html>

<html>

<body>



<asp:Button id="button1" runat="server" Text="Check" OnClick="button1_Click" />

</form>


</body>

</html>

Or



void button1_Click(Object sender, EventArgs e)

{

label1.Text = findAreaCode(textBox1.Text);

}

</script>

<script runat="server" Src="areacode.cs"></script>

<!Doctype html>

<html>

<body>



<asp:Button id="button1" runat="server" Text="Check" OnClick="button1_Click" />

</form>



</body>

</html>



.docx).






Sub Page_Load()

If Not IsPostBack Then


ShowFrom()

Else


End If

End Sub

Sub ShowFrom()

Dim form1 As New HtmlForm()

form1.ID = "Form1"

form1.Method = "post"

Dim button1 As New Button()

button1.Text = "Use UTM Time Zone"

form1.Controls.Add(button1)

Controls.Add(form1)

ENd Sub

</script>

<!Doctype html>

<html><body>



</body></html>

Or



void Page_Load()

{

if (! IsPostBack)

{



ShowFrom();

}

else

{


}

}

void ShowFrom()

{

HtmlForm form1 = new HtmlForm();

form1.ID = "Form1";

form1.Method = "post";

Button button1 = new Button();

button1.Text = "Use UTM Time Zone";

form1.Controls.Add(button1);

Controls.Add(form1);

}

</script>

<!Doctype html>

<html><body>



</body></html>


and


.docx).

Submittal 1. Complete all the 5 learning activities in this lab.

2. Create a .zip file named lab1.zip containing ONLY the following self-executable files.

Lab1_1.aspx

Lab1_2.aspx

Lab1_3.aspx

Lab1_4.aspx

Lab1_5.aspx

Lab1.doc (or .docx)

3. Upload the zipped file as response to question 11 of the Assignment (available at Blackboard).

Programming Exercise #01

1. Use Notepad to create a new text file named “ex01.aspx” with the following lines as heading.

<%--Heading

Student: YourFullName

'File name: ex01.aspx

--%>


2. Next to the above heading, write ASP.NET code that will use as Labe control to display a string “Welcome

come to YourFullName’s ASP.NET site.”, as shown below.

Figure Ex01

3. Download the “programming exercise template”, and rename it to ex01.doc. Capture a screen similar to “Figure

Ex01” and paste it to a Microsoft Word document named “ex01.doc” (or “ex01.docx”).

4. Compress both ex01.aspx and ex01.doc(x) to a .zip file named “ex01.zip”.

5. Upload the zipped file as response to question 12 of the Assignment. Important Note: Your code must be fully

functional to earn the credit. No partial credit is given. You will be given zero points if either .aspx or .docx is

not submitted.