asp w3schools

8/8/2019 ASP W3schools

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ASP.NET Introduction

ASP.NET is the latest version of Microsoft's Active Server Pages technology (ASP).

What you should already know

Before you continue you should have a basic understanding of the following:

WWW, HTML and the basics of building Web pages

Scripting languages like JavaScript or VBScript

The basics of server side scripting

What is ASP?

ASP is a server side scripting technology that enables scripts (embedded in web pages) to beexecuted by an Internet server.

ASP is a Microsoft Technology

ASP stands for Active Server Pages

ASP is a program that runs inside IIS

IIS stands for Internet Information Services

IIS comes as a free component with Windows 2000

IIS is also a part of the Windows NT 4.0 Option Pack

The Option Pack can be downloaded from Microsoft

PWS is a smaller - but fully functional - version of IIS

PWS can be found on your Windows 95/98 CD

What is an ASP File?

An ASP file is just the same as an HTML file

An ASP file can contain text, HTML, XML, and scripts

Scripts in an ASP file are executed on the server

An ASP file has the file extension ".asp"

How Does it Work?

When a browser requests an HTML file, the server returns the file

When a browser requests an ASP file, IIS passes the request to the ASP engine on theserver

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

Finally, the ASP file is returned to the browser as plain HTML

Before you study ASP .NET, it would help to have a basic understanding of Microsoft's ASPtechnology.

What is ASP+?


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ASP+ is the same as ASP.NET.

ASP+ is just an early name used by Microsoft when they developed ASP.NET.

What is ASP.NET?

ASP 3.0 is the latest version of ASP, but there will never be an ASP 4.0 version.

ASP.NET is the next generation ASP, but it's not an upgraded version of ASP. ASP.NET is an entirelynew paradigm for server-side ASP scripting.

ASP.NET is a part of the .NET Framework. Microsoft spent three years rewriting ASP.NET from theground up, and ASP.NET is not fully backward compatible with ASP 3.0.

.NET Framework

The .NET Framework is the infrastructure for the Microsoft .NET platform.

The .NET Framework is an environment for building, deploying, and running Web applications and

Web Services.

The .NET Framework contains a common language runtime and common class libraries - likeADO.NET, ASP.NET and Windows Forms - to provide advanced standard services that can beintegrated into a variety of computer systems.

The .NET Framework provides a feature-rich application environment, simplified development andeasy integration between a number of different development languages.

The .NET Framework is language neutral. Currently it supports C++, C#, Visual Basic, and JScript(Microsoft's version of JavaScript).

Microsoft's Visual Studio.NET is a common development environment for the .NET Framework.

Differences between ASP and ASP .NET

ASP .NET has better language support, a large set of new controls and XML basedcomponents, and better user authentication.

ASP .NET provides increased performance by running compiled code.

ASP .NET code is not fully backward compatible with ASP.New in ASP .NET

Better language support

Programmable controls

Event-driven programming

XML-based components

User authentication, with accounts and roles

Higher scalability

Increased performance - Compiled code

Easier configuration and deployment

Not fully ASP compatible

Language Support

ASP .NET uses the new ADO .NET.


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ASP .NET supports full Visual Basic, not VBScript.

ASP .NET supports C# (C sharp) and C++.

ASP .NET supports JScript as before.

ASP .NET Controls

ASP .NET contains a large set of HTML controls. Almost all HTML elements on a page can be definedas ASP .NET control objects that can be controlled by scripts.

ASP .NET also contains a new set of object oriented input controls, like programmable list boxes andvalidation controls.

A new data grid control supports sorting, data paging, and everything you expect from a datasetcontrol.

Event Aware Controls

All ASP .NET objects on a Web page can expose events that can be processed by ASP .NET code.

Load, Click and Change events handled by code makes coding much simpler and much betterorganized.

ASP .NET Components

ASP .NET components are heavily based on XML. Like the new AD Rotator, that uses XML to storeadvertisement information and configuration.

User Authentication

ASP .NET supports forms-based user authentication, including cookie management and automaticredirecting of unauthorized logins.

(You can still do your custom login page and custom user checking).

User Accounts and Roles

ASP .NET allows for user accounts and roles, to give each user (with a given role) access to differentserver code and executables.

High Scalability

Much has been done with ASP .NET to provide greater scalability.

Server to server communication has been greatly enhanced, making it possible to scale anapplication over several servers. One example of this is the ability to run XML parsers, XSLtransformations and even resource hungry session objects on other servers.


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Compiled Code

The first request for an ASP .NET page on the server will compile the ASP .NET code and keep acached copy in memory. The result of this is greatly increased performance.

Easy Configuration

Configuration of ASP .NET is done with plain text files.

Configuration files can be uploaded or changed while the application is running. No need to restartthe server. No more metabase or registry puzzle.

Easy Deployment

No more server restart to deploy or replace compiled code. ASP .NET simply redirects all newrequests to the new code.

Compatibility

ASP .NET is not fully compatible with earlier versions of ASP, so most of the old ASP code will needsome changes to run under ASP .NET.

To overcome this problem, ASP .NET uses a new file extension ".aspx". This will make ASP .NETapplications able to run side by side with standard ASP applications on the same server.

Installing ASP.NET

ASP.NET is easy to install. Just follow the instructions below.

What You Need


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A Windows Computer

ASP.NET is a Microsoft technology. To run ASP.NET you need a computer capable of runningWindows.

Windows 2000 or XP

If you are serious about developing ASP.NET applications you should install Windows 2000

Professional or Windows XP Professional.

In both cases, make sure you install the Internet Information Services (IIS) from the Add/RemoveWindows components dialog.

Service Packs and Updates

Before ASP.NET can be installed on your computer, it is necessary to have all relevant service packsand security updates installed.

The easiest way to do this is to activate your Windows Internet Update. When you access theWindows Update page, you will be instructed to install the latest service packs and all criticalsecurity updates. For Windows 2000, make sure you install Service Pack 2. I will also recommend

that you install Internet Explorer 6.

Read the note about connection speed and download time at the bottom of this page.

Remove Your Beta Version

If you have a Beta version of ASP.NET installed, we recommend that you completely uninstall it. Oreven better: start with a fresh Windows 2000 or XP installation.

Install .NET

From your Windows Update you can now select to install the Microsoft .NET Framework.

After download, the .NET framework will install itself on your computer - there are no options toselect for installation.

You should now be ready to develop your first ASP.NET application!

The .NET Software Development Kit

If you have the necessary bandwidth to download over 130 MB, you might consider downloadingthe full Microsoft .NET Software Development Kit (SDK).

We fully recommend getting the SDK for learning more about .NET and for the documentation,samples, and tools included.

Connection Speed and Download Time

If you have a slow Internet connection, you might have problems downloading large files like theservice packs, the SDK and the latest version of Internet Explorer.

If download speed is a problem, our best suggestion is to get the latest files from someone else,from a colleague, from a friend, or from one of the CDs that comes with many popular computermagazines. Look for Windows 2000 Service Pack 2, Internet Explorer 6, and the Microsoft .NET

Framework.


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ASP.NET - Web Pages

A simple ASP.NET page looks just like an ordinary HTML page.

Hello W3Schools

To start learning ASP.NET, we will construct a very simple HTML page that will display "HelloW3Schools" in an Internet browser like this:

Hello W3Schools!

Hello W3Schools in HTML

This code displays the example as an HTML page:

Hello W3Schools!

If you want to try it yourself, save the code in a file called "firstpage.htm", and create a link to thefile like this: firstpage.htm

Hello W3Schools in ASP.NET

The simplest way to convert an HTML page into an ASP.NET page is to copy the HTML file to a newfile with an .aspx extension.

This code displays our example as an ASP.NET page:

Hello W3Schools!

If you want to try it yourself, save the code in a file called "firstpage.aspx", and create a link tothe file like this: firstpage.aspx

How Does it Work?

Fundamentally an ASP.NET page is just the same as an HTML page.


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An HTML page has the extension .htm. If a browser requests an HTML page from the server, theserver sends the page to the browser without any modifications.

An ASP.NET page has the extension .aspx. If a browser requests an ASP.NET page, the serverprocesses any executable code in the page, before the result is sent back to the browser.

The ASP.NET page above does not contain any executable code, so nothing is executed. In the nextexamples we will add some executable code to the page to demonstrate the difference between

static HTML pages and dynamic ASP pages.

Classic ASP

Active Server Pages (ASP) has been around for several years. With ASP, executable code can beplaced inside HTML pages.

Previous versions of ASP (before ASP .NET) are often called Classic ASP.

ASP .NET is not fully compatible with Classic ASP, but most Classic ASP pages will work fine asASP .NET pages, with only minor changes.

Dynamic Page in Classic ASP

To demonstrate how ASP can display pages with dynamic content, we have added some executablecode (in red) to the previous example:

Hello W3Schools!

The code inside the tags is executed on the server.

Response.Write is ASP code for writing something to the HTML output stream.

Now() is a function returning the servers current date and time.

If you want to try it yourself, save the code in a file called "dynpage.asp", and create a link to thefile like this: dynpage.asp

Dynamic Page in ASP .NET

This following code displays our example as an ASP .NET page:

Hello W3Schools!

If you want to try it yourself, save the code in a file called "dynpage.aspx", and create a link to thefile like this: dynpage.aspx


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ASP .NET vs Classic ASP

The previous examples didn't demonstrate any differences between ASP .NET and Classic ASP.

As you can see from the two latest examples there are no differences between the two ASP and ASP.NET pages.

In the next chapters you will see how server controls make ASP. NET more powerful than Classic

ASP.

ASP .NET Controls

ASP.NET - Server Controls

Server controls are tags that are understood by the server.

Limitations in Classic ASP

The listing below was copied from the previous chapter:

Hello W3Schools!


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The code above illustrates a limitation in Classic ASP: The code block has to be placed where youwant the output to appear.

With Classic ASP it is impossible to separate executable code from the HTML itself. This makes thepage difficult to read, and difficult to maintain.

ASP.NET - Server Controls

ASP.NET has solved the "spaghetti-code" problem described above with server controls.

Server controls are tags that are understood by the server.

There are three kinds of server controls:

HTML Server Controls - Traditional HTML tags

Web Server Controls - New ASP.NET tags

Validation Server Controls - For input validation

ASP.NET - HTML Server Controls

HTML server controls are HTML tags understood by the server.

HTML elements in ASP.NET files are, by default, treated as text. To make these elementsprogrammable, add a runat="server" attribute to the HTML element. This attribute indicates thatthe element should be treated as a server control. The id attribute is added to identify the servercontrol. The id reference can be used to manipulate the server control at run time.

Note: All HTML server controls must be within a tag with the runat="server" attribute. Therunat="server" attribute indicates that the form should be processed on the server. It also indicatesthat the enclosed controls can be accessed by server scripts.

In the following example we declare an HtmlAnchor server control in an .aspx file. Then we

manipulate the HRef attribute of the HtmlAnchor control in an event handler (an event handler is asubroutine that executes code for a given event). The Page_Load event is one of many events thatASP.NET understands:

Sub Page_Loadlink1.HRef="http://www.w3schools.com"End SubVisit W3Schools!

The executable code itself has been moved outside the HTML.

ASP.NET - Web Server Controls

Web server controls are special ASP.NET tags understood by the server.

Like HTML server controls, Web server controls are also created on the server and they require arunat="server" attribute to work. However, Web server controls do not necessarily map to anyexisting HTML elements and they may represent more complex elements.


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The syntax for creating a Web server control is:

In the following example we declare a Button server control in an .aspx file. Then we create anevent handler for the Click event which changes the text on the button:

Sub submit(Source As Object, e As EventArgs)button1.Text="You clicked me!"End Sub

ASP.NET - Validation Server Controls

Validation server controls is used to validate user-input. If the user-input does not pass validation, itwill display an error message to the user.

Each validation control performs a specific type of validation (like validating against a specific valueor a range of values).

By default, page validation is performed when a Button, ImageButton, or LinkButton control isclicked. You can prevent validation when a button control is clicked by setting the CausesValidationproperty to false.

The syntax for creating a Validation server control is:

In the following example we declare one TextBox control, one Button control, and oneRangeValidator control in an .aspx file. If validation fails, the text "The value must be from 1 to100!" will be displayed in the RangeValidator control:

Enter a number from 1 to 100:


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ASP.NET - Events

An Event Handler is a subroutine that executes code for a given event.

ASP.NET - Event Handlers

Look at the following code:

When will the code above be executed? The answer is: "You don't know..."

The Page_Load Event

The Page_Load event is one of many events that ASP.NET understands. The Page_Load event istriggered when a page loads, and ASP.NET will automatically call the subroutine Page_Load, andexecute the code inside it:

Sub Page_Loadlbl1.Text="The date and time is " & now()End Sub

Note: The Page_Load event contains no object references or event arguments!

Example:


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ASPX Source:

Sub Page_Loadlbl1.Text="The date and time is " & now()

End Sub

Output Result:

The date and time is 3/10/2007 1:42:30 AM

The Page.IsPostBack Property

The Page_Load subroutine runs EVERY time the page is loaded. If you want to execute the code inthe Page_Load subroutine only the FIRST time the page is loaded, you can use the Page.IsPostBackproperty. If the Page.IsPostBack property is false, the page is loaded for the first time, if it is true,the page is posted back to the server (i.e. from a button click on a form):

Sub Page_Loadif Not Page.IsPostBack thenlbl1.Text="The date and time is " & now()

end ifEnd SubSub Submit(s As Object, e As EventArgs)lbl2.Text="Hello World!"End Sub

The example above will write the "The date and time is...." message only the first time the page isloaded. When a user clicks on the Submit button, the submit subroutine will write "Hello World!" tothe second label, but the date and time in the first label will not change.

Example:

ASPX Source:

Sub Page_Loadif Not Page.IsPostBack then

lbl1.Text="The date and time is & now()


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end if

End Sub

Sub Submit(s As Object, e As EventArgs)

lbl2.Text="Hello World!"End Sub

Output Result:

The date and time is 3/10/2007 1:41:21 PM

Submit

ASP.NET Web Forms

All server controls must appear within a tag, and the tag must contain

the runat="server" attribute.

ASP.NET Web Forms

All server controls must appear within a tag, and the tag must contain therunat="server" attribute. The runat="server" attribute indicates that the form should be processedon the server. It also indicates that the enclosed controls can be accessed by server scripts:

...HTML + server controls

Note: The form is always submitted to the page itself. If you specify an action attribute, it is

ignored. If you omit the method attribute, it will be set to method="post" by default. Also, if you donot specify the name and id attributes, they are automatically assigned by ASP.NET.


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Note: An .aspx page can only contain ONE control!

If you select view source in an .aspx page containing a form with no name, method, action, or idattribute specified, you will see that ASP.NET has added these attributes to the form. It lookssomething like this:

...some code

Submitting a Form

A form is most often submitted by clicking on a button. The Button server control in ASP.NET hasthe following format:

The id attribute defines a unique name for the button and the text attribute assigns a label to thebutton. The onClick event handler specifies a named subroutine to execute.

In the following example we declare a Button control in an .aspx file. A button click runs asubroutine which changes the text on the button:

Example:

ASPX Source:

Sub submit (Source As Object, e As EventArgs)

button1.Text="You clicked me!"End Sub

Output Result:

Click me!

ASP .NET Maintaining the ViewState

You may save a lot of coding by maintaining the ViewState of the objects in your WebForm.

Maintaining the ViewState


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When a form is submitted in classic ASP, all form values are cleared. Suppose you have submitted aform with a lot of information and the server comes back with an error. You will have to go back tothe form and correct the information. You click the back button, and what happens.......ALL formvalues are CLEARED, and you will have to start all over again! The site did not maintain yourViewState.

When a form is submitted in ASP .NET, the form reappears in the browser window together with allform values. How come? This is because ASP .NET maintains your ViewState. The ViewStateindicates the status of the page when submitted to the server. The status is defined through ahidden field placed on each page with a control. The source could looksomething like this:

.....some code

Maintaining the ViewState is the default setting for ASP.NET Web Forms. If you want to NOTmaintain the ViewState, include the directive at the top ofan .aspx page or add the attribute EnableViewState="false" to any control.

Look at the following .aspx file. It demonstrates the "old" way to do it. When you click on thesubmit button, the form value will disappear:

Your name:

Example

ASPX Source:

Your name:


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Output Result:

Your name:Submit

Here is the new ASP .NET way. When you click on the submit button, the form value will NOTdisappear:

Sub submit(sender As Object, e As EventArgs)lbl1.Text="Hello " & txt1.Text & "!"End SubYour name:

Example:

(Click view source in the right frame of the example to see that ASP .NET has added a hidden fieldin the form to maintain the ViewState)

ASPX Source:

Sub submit(sender As Object, e As EventArgs)

lbl1.Text="Hello " & txt1.Text & "!"End Sub

Your name:

Output Result:

Your name:Submit

ASP .NET - The TextBox Control

The TextBox control is used to create a text box where the user can input text.


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The TextBox Control

The TextBox control is used to create a text box where the user can input text.

The example below demonstrates some of the attributes you may use with the TextBox control:

Example

ASPX Source:

A basic TextBox:

A password TextBox:

A TextBox with text:

A multiline TextBox:

A TextBox with height:

A TextBox with width:

Output Result:

A basic TextBox:

A password TextBox:






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Add a Script

The contents and settings of a TextBox control may be changed by server scripts when a form issubmitted. A form can be submitted by clicking on a button or when a user changes the value in theTextBox control.

In the following example we declare one TextBox control, one Button control, and one Label controlin an .aspx file. When the submit button is triggered, the submit subroutine is executed. The submitsubroutine writes a text to the Label control:

Sub submit(sender As Object, e As EventArgs)lbl1.Text="Your name is " & txt1.TextEnd SubEnter your name:

Example:

ASPX Source:

A basic TextBox:

A password TextBox:






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lbl1.Text="Your name is " & txt1.TextEnd Sub

Enter your name:

Output Result:

Enter your name:Submit

In the following example we declare one TextBox control and one Label control in an .aspx file.When you change the value in the TextBox and either click outside the TextBox or press the Tabkey, the change subroutine is executed. The submit subroutine writes a text to the Label control:

Sub change(sender As Object, e As EventArgs)lbl1.Text="You changed text to " & txt1.TextEnd SubEnter your name:

Example:

ASPX Source:Sub change(sender As Object, e As EventArgs)

lbl1.Text="You changed text to " & txt1.TextEnd Sub

Change text


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Output Result:

Change text

ASP.NET - The Button Control

The Button control is used to display a push button.

The Button Control

The Button control is used to display a push button. The push button may be a submit button or acommand button. By default, this control is a submit button.

A submit button does not have a command name and it posts the page back to the server when it isclicked. It is possible to write an event handler to control the actions performed when the submitbutton is clicked.A command button has a command name and allows you to create multiple Buttoncontrols on a page. It is possible to write an event handler to control the actions performed whenthe command button is clicked.

The example below demonstrates a simple Button control:

Add a Script

A form is most often submitted by clicking on a button.

In the following example we declare one TextBox control, one Button control, and one Label controlin an .aspx file. When the submit button is triggered, the submit subroutine is executed. The submitsubroutine writes a text to the Label control:

Sub submit(sender As Object, e As EventArgs)lbl1.Text="Your name is " & txt1.TextEnd SubEnter your name:


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Example:

ASPX Source:

Sub submit(sender As Object, e As EventArgs)lbl1.Text="Your name is " & txt1.Text

End Sub

Enter your name:

Output Result:

Enter your name:Submit

ASP.NET - Data Binding

We may use data binding to fill lists with selectable items from an imported data source,like a database, an XML file, or a script.

Data Binding

The following controls are list controls which support data binding:

asp:RadioButtonList

asp:CheckBoxList

asp:DropDownList

asp:Listbox


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The selectable items in each of the above controls are usually defined by one or more asp:ListItemcontrols, like this:

However, with data binding we may use a separate source, like a database, an XML file, or a scriptto fill the list with selectable items.

By using an imported source, the data is separated from the HTML, and any changes to the itemsare made in the separate data source.

ASP.NET - The Array List Object

The ArrayList object is a collection of items containing a single data value.

Examples

Example - ArrayList RadioButtonList

ASPX Source:

Sub Page_Load

if Not Page.IsPostBack thendim mycountries=New ArrayList

mycountries.Add("Norway")mycountries.Add("Sweden")

mycountries.Add("France")mycountries.Add("Italy")

mycountries.TrimToSize()mycountries.Sort()

rb.DataSource=mycountriesrb.DataBind()

end ifend sub

sub displayMessage(s as Object,e As EventArgs)

lbl1.text="Your favorite country is: " & rb.SelectedItem.Textend sub


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Output Result:

France

Italy

Norway

Sweden

Example - ArrayList DropDownList

ASPX Source:

sub Page_Loadif Not Page.IsPostBack then

dim mycountries=New ArrayListmycountries.Add("Norway")

mycountries.Add("Sweden")mycountries.Add("France")

mycountries.Add("Italy")mycountries.TrimToSize()

mycountries.Sort()dd.DataSource=mycountries

dd.DataBind()end if

end sub

sub displayMessage(s as Object,e As EventArgs)lbl1.text="Your favorite country is: " & dd.SelectedItem.Text

end sub

Output Result:


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Create an ArrayList

The ArrayList object is a collection of items containing a single data value.

Items are added to the ArrayList with the Add() method.

The following code creates a new ArrayList object named mycountries and four items are added:

Sub Page_Loadif Not Page.IsPostBack thendim mycountries=New ArrayListmycountries.Add("Norway")mycountries.Add("Sweden")mycountries.Add("France")mycountries.Add("Italy")

end ifend sub

By default, an ArrayList object contains 16 entries. An ArrayList can be sized to its final size with the

TrimToSize() method:

Sub Page_Loadif Not Page.IsPostBack thendim mycountries=New ArrayListmycountries.Add("Norway")mycountries.Add("Sweden")mycountries.Add("France")mycountries.Add("Italy")mycountries.TrimToSize()

end ifend sub

An ArrayList can also be sorted alphabetically or numerically with the Sort() method:

Sub Page_Loadif Not Page.IsPostBack thendim mycountries=New ArrayListmycountries.Add("Norway")mycountries.Add("Sweden")mycountries.Add("France")mycountries.Add("Italy")mycountries.TrimToSize()mycountries.Sort()

end ifend sub

To sort in reverse order, apply the Reverse() method after the Sort() method:

Sub Page_Loadif Not Page.IsPostBack thendim mycountries=New ArrayListmycountries.Add("Norway")mycountries.Add("Sweden")mycountries.Add("France")

mycountries.Add("Italy")


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mycountries.TrimToSize()mycountries.Sort()mycountries.Reverse()

end ifend sub

Data Binding to an ArrayList

An ArrayList object may automatically generate the text and values to the following controls:

asp:RadioButtonList

asp:CheckBoxList

asp:DropDownList

asp:Listbox

To bind data to a RadioButtonList control, first create a RadioButtonList control (without anyasp:ListItem elements) in an .aspx page:

Then add the script that builds the list and binds the values in the list to the RadioButtonListcontrol:

Sub Page_Loadif Not Page.IsPostBack thendim mycountries=New ArrayListmycountries.Add("Norway")mycountries.Add("Sweden")mycountries.Add("France")mycountries.Add("Italy")mycountries.TrimToSize()mycountries.Sort()rb.DataSource=mycountriesrb.DataBind()

end ifend sub

The DataSource property of the RadioButtonList control is set to the ArrayList and it defines thedata source of the RadioButtonList control. The DataBind() method of the RadioButtonList controlbinds the data source with the RadioButtonList control.

Note: The data values are used as both the Text and Value properties for the control. To add Valuesthat are different from the Text, use either the Hashtable object or the SortedList object.


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ASP.NET - The Hashtable Object

The Hashtable object contains items in key/value pairs.

Examples

Example - Hashtable RadioButtonList

ASPX Source:


dim mycountries=New Hashtablemycountries.Add("N","Norway")

mycountries.Add("S","Sweden")

mycountries.Add("F","France")mycountries.Add("I","Italy")rb.DataSource=mycountries

rb.DataValueField="Key"rb.DataTextField="Value"

rb.DataBind()end if

end sub


lbl1.text="Your favorite country is: " & rb.SelectedItem.Textend sub

Output Result:

Norway

Italy

Sweden

France

Example - Hashtable RadiobuttonList

ASPX Source:


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sub Page_Load

if Not Page.IsPostBack thendim navigate=New Hashtable

navigate.Add("RadioButtonList","control_radiobuttonlist.asp")navigate.Add("CheckBoxList","control_checkboxlist.asp")

navigate.Add("DropDownList","control_dropdownlist.asp")

navigate.Add("ListBox","control_listbox.asp")rb.DataSource=navigaterb.DataValueField="Value"

rb.DataTextField="Key"rb.DataBind()

end ifend sub

sub navigate(s as Object, e As EventArgs)

response.redirect(rb.SelectedItem.Value)end sub

Output Result:

DropDownList

RadioButtonList

CheckBoxList

ListBox

Example - Hashtable DropDownList

ASPX Source:


dim mycountries=New Hashtablemycountries.Add("N","Norway")

mycountries.Add("S","Sweden")mycountries.Add("F","France")

mycountries.Add("I","Italy")

dd.DataSource=mycountries


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dd.DataValueField="Key"

dd.DataTextField="Value"

dd.DataBind()end if

end sub


lbl1.text="Your favorite country is: " & dd.SelectedItem.Textend sub

Output Result:

Create a Hashtable

The Hashtable object contains items in key/value pairs. The keys are used as indexes, and veryquick searches can be made for values by searching through their keys.

Items are added to the Hashtable with the Add() method.

The following code creates a Hashtable named mycountries and four elements are added:

Sub Page_Loadif Not Page.IsPostBack thendim mycountries=New Hashtablemycountries.Add("N","Norway")mycountries.Add("S","Sweden")mycountries.Add("F","France")mycountries.Add("I","Italy")

end ifend sub

Data Binding

A Hashtable object may automatically generate the text and values to the following controls:


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asp:RadioButtonList

asp:CheckBoxList

asp:DropDownList

asp:Listbox


Then add the script that builds the list:

sub Page_Loadif Not Page.IsPostBack thendim mycountries=New Hashtablemycountries.Add("N","Norway")mycountries.Add("S","Sweden")mycountries.Add("F","France")mycountries.Add("I","Italy")rb.DataSource=mycountriesrb.DataValueField="Key"rb.DataTextField="Value"rb.DataBind()

end ifend sub

Then we add a sub routine to be executed when the user clicks on an item in the RadioButtonListcontrol. When a radio button is clicked, a text will appear in a label:

sub Page_Load

if Not Page.IsPostBack thendim mycountries=New Hashtablemycountries.Add("N","Norway")mycountries.Add("S","Sweden")mycountries.Add("F","France")mycountries.Add("I","Italy")rb.DataSource=mycountriesrb.DataValueField="Key"rb.DataTextField="Value"rb.DataBind()

end ifend subsub displayMessage(s as Object,e As EventArgs)lbl1.text="Your favorite country is: " & rb.SelectedItem.Text

end sub


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Note: You cannot choose the sort order of the items added to the Hashtable. To sort itemsalphabetically or numerically, use the SortedList object.

ASP.NET - The Sorted List Object

The SortedList object combines the features of both the ArrayList object and the

Hashtable object.

Examples

Example - SortedList RadioButtonList

ASPX Source:

sub Page_Load

if Not Page.IsPostBack thendim mycountries=New SortedList

mycountries.Add("N","Norway")mycountries.Add("S","Sweden")

mycountries.Add("F","France")mycountries.Add("I","Italy")

rb.DataSource=mycountriesrb.DataValueField="Key"

rb.DataTextField="Value"rb.DataBind()

end ifend sub


lbl1.text="Your favorite country is: " & rb.SelectedItem.Text

end sub


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Output Result:

France

Italy

Norway

Sweden

Example - SortedList RadiobuttonList

ASPX Source:


dim navigate=New SortedListnavigate.Add("RadioButtonList","control_radiobuttonlist.asp")

navigate.Add("CheckBoxList","control_checkboxlist.asp")navigate.Add("DropDownList","control_dropdownlist.asp")

navigate.Add("ListBox","control_listbox.asp")rb.DataSource=navigate

rb.DataValueField="Value"rb.DataTextField="Key"

rb.DataBind()end if

end sub

sub navigate(s as Object, e As EventArgs)response.redirect(rb.SelectedItem.Value)

end sub

Output Result:

CheckBoxList

DropDownList


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ListBox

RadioButtonList

Example - SortedList DropDownList

ASPX Source:


dim mycountries=New SortedListmycountries.Add("N","Norway")

mycountries.Add("S","Sweden")mycountries.Add("F","France")

mycountries.Add("I","Italy")dd.DataSource=mycountries

dd.DataValueField="Key"dd.DataTextField="Value"

dd.DataBind()end if

end sub

sub displayMessage(s as Object,e As EventArgs)lbl1.text="Your favorite country is: " & dd.SelectedItem.Text

end sub

Output Result:

The SortedList Object

The SortedList object contains items in key/value pairs. A SortedList object automatically sort theitems in alphabetic or numeric order.

Items are added to the SortedList with the Add() method. A SortedList can be sized to its final sizewith the TrimToSize() method.

The following code creates a SortedList named mycountries and four elements are added:


dim mycountries=New SortedList


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mycountries.Add("N","Norway")mycountries.Add("S","Sweden")mycountries.Add("F","France")mycountries.Add("I","Italy")

end ifend sub

Data Binding

A SortedList object may automatically generate the text and values to the following controls:

asp:RadioButtonList

asp:CheckBoxList

asp:DropDownList

asp:Listbox


Then add the script that builds the list:

sub Page_Load

if Not Page.IsPostBack thendim mycountries=New SortedListmycountries.Add("N","Norway")mycountries.Add("S","Sweden")mycountries.Add("F","France")mycountries.Add("I","Italy")rb.DataSource=mycountriesrb.DataValueField="Key"rb.DataTextField="Value"rb.DataBind()

end ifend sub


sub Page_Load

if Not Page.IsPostBack thendim mycountries=New SortedList


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mycountries.Add("N","Norway")mycountries.Add("S","Sweden")mycountries.Add("F","France")mycountries.Add("I","Italy")rb.DataSource=mycountriesrb.DataValueField="Key"rb.DataTextField="Value"rb.DataBind()

end ifend subsub displayMessage(s as Object,e As EventArgs)lbl1.text="Your favorite country is: " & rb.SelectedItem.Textend sub

ASP .NET - XML Files

We can bind an XML file to a list control.

Examples

Example - XML RadiobuttonList

ASPX Source:

sub Page_Load

if Not Page.IsPostBack thendim mycountries=New DataSet

mycountries.ReadXml(MapPath("countries.xml"))rb.DataSource=mycountries

rb.DataValueField="value"rb.DataTextField="text"

rb.DataBind()end if

end sub

sub displayMessage(s as Object,e As EventArgs)lbl1.text="Your favorite country is: " & rb.SelectedItem.Text

end sub


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Output Result:

Norway

Sweden

France

Italy

An XML File

Here is an XML file named "countries.xml":

NorwayN

SwedenSFranceFItalyI

Take a look at the XML file: countries.xml

Bind a DataSet to a List Control

First, import the "System.Data" namespace. We need this namespace to work with DataSet objects.Include the following directive at the top of an .aspx page:

Next, create a DataSet for the XML file and load the XML file into the DataSet when the page is firstloaded:


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sub Page_Loadif Not Page.IsPostBack thendim mycountries=New DataSetmycountries.ReadXml(MapPath("countries.xml"))

end ifend sub

To bind the DataSet to a RadioButtonList control, first create a RadioButtonList control (without anyasp:ListItem elements) in an .aspx page:

Then add the script that builds the XML DataSet:

sub Page_Loadif Not Page.IsPostBack thendim mycountries=New DataSetmycountries.ReadXml(MapPath("countries.xml"))rb.DataSource=mycountriesrb.DataValueField="value"

rb.DataTextField="text"rb.DataBind()end ifend sub


sub Page_Loadif Not Page.IsPostBack thendim mycountries=New DataSetmycountries.ReadXml(MapPath("countries.xml"))rb.DataSource=mycountriesrb.DataValueField="value"rb.DataTextField="text"rb.DataBind()

end if

end sub


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sub displayMessage(s as Object,e As EventArgs)lbl1.text="Your favorite country is: " & rb.SelectedItem.Textend sub

ASP.NET - The Repeater Control

The Repeater control is used to display a repeated list of items that are bound to thecontrol.

Examples

Repeater control

ASPX Source:


dim mycdcatalog=New DataSetmycdcatalog.ReadXml(MapPath("cdcatalog.xml"))

cdcatalog.DataSource=mycdcatalogcdcatalog.DataBind()

end ifend sub


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Title

Artist

CompanyPrice

Output Result:

Title Artist Company Price

Empire Burlesque Bob Dylan Columbia 10.90

Hide your heart Bonnie Tyler CBS Records 9.90

Greatest Hits Dolly Parton RCA 9.90

Still got the blues Gary Moore Virgin records 10.20

Eros Eros Ramazzotti BMG 9.90

Repeater control with

ASPX Source:


dim mycdcatalog=New DataSet

mycdcatalog.ReadXml(MapPath("cdcatalog.xml"))cdcatalog.DataSource=mycdcatalog

cdcatalog.DataBind()end if

end sub


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TitleArtist

Company

Price

Output Result:

Title Artist Company Price

Empire Burlesque Bob Dylan Columbia 10.90

Hide your heart Bonnie Tyler CBS Records 9.90

Greatest Hits Dolly Parton RCA 9.90

Still got the blues Gary Moore Virgin records 10.20Eros Eros Ramazzotti BMG 9.90

Repeater control with

ASPX Source:

sub Page_Load

if Not Page.IsPostBack then


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dim mycdcatalog=New DataSet

mycdcatalog.ReadXml(MapPath("cdcatalog.xml"))


end ifend sub

Title

ArtistCompany

Price

Bind a DataSet to a Repeater Control

The Repeater control is used to display a repeated list of items that are bound to the control. TheRepeater control may be bound to a database table, an XML file, or another list of items. Here wewill show how to bind an XML file to a Repeater control.

We will use the following XML file in our examples ("cdcatalog.xml"):


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Empire BurlesqueBob DylanUSAColumbia10.90

1985Hide your heartBonnie TylerUKCBS Records9.901988Greatest HitsDolly PartonUSARCA9.901982Still got the bluesGary MooreUKVirgin records10.201990ErosEros Ramazzotti

EUBMG9.901997

Take a look at the XML file: cdcatalog.xml

-

title>Empire Burlesque

artist>Bob Dylancountry>USA

company>Columbia

price>10.90year>1985

title>Hide your heart

artist>Bonnie Tylercountry>UK

company>CBS Recordsprice>9.90

year>1988

title>Greatest Hits

artist>Dolly Partoncountry>USA

company>RCAprice>9.90

year>1982

title>Still got the blues

artist>Gary Moore

country>UKcompany>Virgin recordsprice>10.20

year>1990

title>Eros

artist>Eros Ramazzotticountry>EU

company>BMGprice>9.90

year>1997
http://www.w3schools.com/aspnet/cdcatalog.xml#%23http://www.w3schools.com/aspnet/cdcatalog.xml#%23http://www.w3schools.com/aspnet/cdcatalog.xml#%23http://www.w3schools.com/aspnet/cdcatalog.xml#%23http://www.w3schools.com/aspnet/cdcatalog.xml#%23http://www.w3schools.com/aspnet/cdcatalog.xml#%23http://www.w3schools.com/aspnet/cdcatalog.xml#%23http://www.w3schools.com/aspnet/cdcatalog.xml#%23http://www.w3schools.com/aspnet/cdcatalog.xml#%23http://www.w3schools.com/aspnet/cdcatalog.xml#%23http://www.w3schools.com/aspnet/cdcatalog.xml#%23http://www.w3schools.com/aspnet/cdcatalog.xml#%23


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end ifend sub

Then we create a Repeater control in an .aspx page. The contents of the element are rendered first and only once within the output, then the contents of the element are repeated for each "record" in the DataSet, and last, the contents ofthe element are rendered once within the output:

.........


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Then we add the script that creates the DataSet and binds the mycdcatalog DataSet to the Repeatercontrol. We also fill the Repeater control with HTML tags and bind the data items to the cells inthe section with the method:


dim mycdcatalog=New DataSetmycdcatalog.ReadXml(MapPath("cdcatalog.xml"))cdcatalog.DataSource=mycdcatalogcdcatalog.DataBind()

end ifend sub

TitleArtistCountryCompanyPriceYear

Using the

You can add an element after the element to describethe appearance of alternating rows of output. In the following example each other row in the tablewill be displayed in a light grey color:

sub Page_Loadif Not Page.IsPostBack thendim mycdcatalog=New DataSetmycdcatalog.ReadXml(MapPath("cdcatalog.xml"))cdcatalog.DataSource=mycdcatalogcdcatalog.DataBind()

end if

end sub


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Title

ArtistCountryCompanyPriceYear

Using the

The element can be used to describe a separator between each record. Thefollowing example inserts a horizontal line between each table row:


end ifend sub


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TitleArtistCountryCompanyPriceYear

ASP.NET - The DataList Control

The DataList control is, like the Repeater control, used to display a repeated list of itemsthat are bound to the control. However, the DataList control adds a table around the dataitems by default.

Examples

DataList control

ASPX Source:

sub Page_Load

if Not Page.IsPostBack thendim mycdcatalog=New DataSet

mycdcatalog.ReadXml(MapPath("cdcatalog.xml"))cdcatalog.DataSource=mycdcatalog

cdcatalog.DataBind()end if

end sub


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My CD Catalog

"" of - $

Hege Refsnes

Output Result:

My CD Catalog

"Empire Burlesque" of Bob Dylan - $10.90

"Hide your heart" of Bonnie Tyler - $9.90

"Greatest Hits" of Dolly Parton - $9.90

"Still got the blues" of Gary Moore - $10.20"Eros" of Eros Ramazzotti - $9.90

Hege Refsnes

DataList control with styles

ASPX Source:




end ifend sub


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My CD Catalog

"" of - $

Hege Refsnes

Output Result:

My CD Catalog




"Still got the blues" of Gary Moore - $10.20

"Eros" of Eros Ramazzotti - $9.90 Hege Refsnes

DataList control with

ASPX Source:

sub Page_Load

if Not Page.IsPostBack thendim mycdcatalog=New DataSet

mycdcatalog.ReadXml(MapPath("cdcatalog.xml"))

cdcatalog.DataSource=mycdcatalog


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cdcatalog.DataBind()

end if

end sub

My CD Catalog

"" of - $

"" of - $

Hege Refsnes

Output Result:

My CD Catalog




"Still got the blues" of Gary Moore - $10.20


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"Eros" of Eros Ramazzotti - $9.90 Hege Refsnes

Bind a DataSet to a DataList Control

The DataList control is, like the Repeater control, used to display a repeated list of items that arebound to the control. However, the DataList control adds a table around the data items by default.

The DataList control may be bound to a database table, an XML file, or another list of items. Herewe will show how to bind an XML file to a DataList control.

We will use the following XML file in our examples ("cdcatalog.xml"):

Empire BurlesqueBob DylanUSAColumbia10.901985

Hide your heartBonnie TylerUKCBS Records9.901988Greatest HitsDolly PartonUSARCA

9.901982Still got the bluesGary MooreUKVirgin records10.201990ErosEros Ramazzotti

EUBMG9.901997

Take a look at the XML file: cdcatalog.xml



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sub Page_Loadif Not Page.IsPostBack thendim mycdcatalog=New DataSetmycdcatalog.ReadXml(MapPath("cdcatalog.xml"))

end ifend sub

Then we create a DataList in an .aspx page. The contents of the element arerendered first and only once within the output, then the contents of the elementare repeated for each "record" in the DataSet, and last, the contents of the element are rendered once within the output:

.........

Then we add the script that creates the DataSet and binds the mycdcatalog DataSet to the DataList

control. We also fill the DataList control with a that contains the header of thetable, an that contains the data items to display, and a thatcontains a text. Note that the gridlines attribute of the DataList is set to "both" to display tableborders:


end if

end subMy CD Catalog"" of -$


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Copyright Hege Refsnes

Using Styles

You can also add styles to the DataList control to make the output more fancy:


end ifend sub

My CD Catalog"" of -$

Copyright Hege Refsnes

Using the

You can add an element after the element to describethe appearance of alternating rows of output. You may style the data in the section within the DataList control:


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sub Page_Loadif Not Page.IsPostBack thendim mycdcatalog=New DataSetmycdcatalog.ReadXml(MapPath("cdcatalog.xml"))cdcatalog.DataSource=mycdcatalogcdcatalog.DataBind()end if

end subMy CD Catalog"" of -$

"" of -$ Hege Refsnes

ASP.NET - Database Connection

ADO.NET is also a part of the .NET Framework. ADO.NET is used to handle data access.

With ADO.NET you can work with databases.

Examples

Database connection - Bind to a Repeater control


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ASPX Source:

sub Page_Loaddim dbconn,sql,dbcomm,dbread

dbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;data source=" &

server.mappath("/db/northwind.mdb"))dbconn.Open()

sql="SELECT * FROM customers"dbcomm=New OleDbCommand(sql,dbconn)

dbread=dbcomm.ExecuteReader()customers.DataSource=dbread

customers.DataBind()dbread.Close()

dbconn.Close()end sub

Companyname

Contactname

AddressCity


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Output Result:

Companyname Contactname Address City

Alfreds Futterkiste Maria Anders Obere Str. 57 Berlin

Berglunds snabbkp Christina Berglund Berguvsvgen 8 Lule

Centro comercial

MoctezumaFrancisco Chang

Sierras de Granada

9993Mxico D.F.

Ernst Handel Roland Mendel Kirchgasse 6 Graz

FISSA Fabrica Inter.Salchichas S.A.

Diego Roel C/ Moralzarzal, 86 Madrid

Galera del gastrnomo Eduardo SaavedraRambla de Catalua,23

Barcelona

Island Trading Helen BennettGarden HouseCrowther Way

Cowes

Kniglich Essen Philip Cramer Maubelstr. 90 Brandenburg

Laughing Bacchus WineCellars Yoshi Tannamuri 1900 Oak St. Vancouver

Magazzini AlimentariRiuniti

Giovanni RovelliVia Ludovico il Moro22

Bergamo

North/South Simon CrowtherSouth House 300Queensbridge

London

Paris spcialits Marie Bertrand265, boulevardCharonne

Paris

Rattlesnake CanyonGrocery

Paula Wilson 2817 Milton Dr. Albuquerque

Simons bistro Jytte Petersen Vinbltet 34 Kbenhavn

The Big Cheese Liz Nixon89 Jefferson Way Suite2

Portland

Vaffeljernet Palle Ibsen Smagslget 45 rhus

Wolski ZajazdZbyszekPiestrzeniewicz

ul. Filtrowa 68 Warszawa

Database connection - Bind to a DataList control

ASPX Source:

sub Page_Load

dim dbconn,sql,dbcomm,dbreaddbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;data source=" &

server.mappath("/db/northwind.mdb"))dbconn.Open()

sql="SELECT * FROM customers"dbcomm=New OleDbCommand(sql,dbconn)

dbread=dbcomm.ExecuteReader()


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customers.DataSource=dbread

customers.DataBind()

dbread.Close()dbconn.Close()

end sub

Customers Table

in

,

Source: Northwind Database

Output Result:

Customers Table

Alfreds Futterkiste in Obere Str. 57, Berlin

Berglunds snabbkp in Berguvsvgen 8, Lule

Centro comercial Moctezuma in Sierras de Granada 9993, Mxico D.F.

Ernst Handel in Kirchgasse 6, Graz

FISSA Fabrica Inter. Salchichas S.A. in C/ Moralzarzal, 86, Madrid

Galera del gastrnomo in Rambla de Catalua, 23, Barcelona

Island Trading in Garden House Crowther Way, Cowes


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Kniglich Essen in Maubelstr. 90, Brandenburg

Laughing Bacchus Wine Cellars in 1900 Oak St., Vancouver

Magazzini Alimentari Riuniti in Via Ludovico il Moro 22, Bergamo

North/South in South House 300 Queensbridge, London

Paris spcialits in 265, boulevard Charonne, Paris

Rattlesnake Canyon Grocery in 2817 Milton Dr., AlbuquerqueSimons bistro in Vinbltet 34, Kbenhavn

The Big Cheese in 89 Jefferson Way Suite 2, Portland

Vaffeljernet in Smagslget 45, rhus

Wolski Zajazd in ul. Filtrowa 68, WarszawaSource: Northwind Database

What is ADO.NET?

ADO.NET is a part of the .NET Framework

ADO.NET consists of a set of classes used to handle data access

ADO.NET is entirely based on XML ADO.NET has, unlike ADO, no Recordset object

Create a Database Connection

We are going to use the Northwind database in our examples.

First, import the "System.Data.OleDb" namespace. We need this namespace to work with MicrosoftAccess and other OLE DB database providers. We will create the connection to the database in thePage_Load subroutine. We create a dbconn variable as a new OleDbConnection class with aconnection string which identifies the OLE DB provider and the location of the database. Then weopen the database connection:

sub Page_Loaddim dbconndbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;data source=" & server.mappath("northwind.mdb"))dbconn.Open()end sub

Note: The connection string must be a continuous string without a line break!

Create a Database Command

To specify the records to retrieve from the database, we will create a dbcomm variable as a newOleDbCommand class. The OleDbCommand class is for issuing SQL queries against database tables:

sub Page_Loaddim dbconn,sql,dbcommdbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;data source=" & server.mappath("northwind.mdb"))dbconn.Open()sql="SELECT * FROM customers"

dbcomm=New OleDbCommand(sql,dbconn)


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end sub

Create a DataReader

The OleDbDataReader class is used to read a stream of records from a data source. A DataReader iscreated by calling the ExecuteReader method of the OleDbCommand object:

sub Page_Loaddim dbconn,sql,dbcomm,dbreaddbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;data source=" & server.mappath("northwind.mdb"))dbconn.Open()sql="SELECT * FROM customers"dbcomm=New OleDbCommand(sql,dbconn)dbread=dbcomm.ExecuteReader()end sub

Bind to a Repeater Control

Then we bind the DataReader to a Repeater control:

sub Page_Loaddim dbconn,sql,dbcomm,dbreaddbconn=New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;data source=" & server.mappath("northwind.mdb"))

dbconn.Open()sql="SELECT * FROM customers"dbcomm=New OleDbCommand(sql,dbconn)dbread=dbcomm.ExecuteReader()customers.DataSource=dbreadcustomers.DataBind()dbread.Close()dbconn.Close()end sub

CompanynameContactnameAddressCity


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Close the Database Connection

Always close both the DataReader and database connection after access to the database is nolonger required:

dbread.Close()

dbconn.Close()

HTML Server Controls

HTML server controls are HTML tags understood by the server.

HTML Server Controls

HTML elements in ASP.NET files are, by default, treated as text. To make these elementsprogrammable, add a runat="server" attribute to the HTML element. This attribute indicates that

the element should be treated as a server control.

Note: All HTML server controls must be within a tag with the runat="server" attribute!

Note: ASP.NET requires that all HTML elements must be properly closed and properly nested.

HTML Server Control Description

HtmlAnchor Controls an HTML element

HtmlButton Controls a HTML element

HtmlForm Controls a HTML element

HtmlGeneric Controls other HTML element not specified by a specific HTML servercontrol, like , , , etc.

HtmlImage Controls an HTML elementHtmlInputButton Controls , , and HTML elements

HtmlInputCheckBox Controls an HTML element

HtmlInputFile Controls an HTML element

HtmlInputHidden Controls an HTML element

HtmlInputImage Controls an HTML element

HtmlInputRadioButton Controls an HTML element

HtmlInputText Controls and HTMLelements

HtmlSelect Controls a HTML element

HtmlTable Controls a HTML element

HtmlTableCell Controls and HTML elementsHtmlTableRow Controls a HTML element


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HtmlTextArea Controls a HTML element

ASP.NET HtmlAnchor Control

Definition and Usage

The HtmlAnchor control is used to control an element. In HTML, the element is used tocreate a hyperlink. The hyperlink may link to a bookmark or to another Web page.

Properties

Property Description

Attributes Returns all attribute name and value pairs of the element

Disabled A Boolean value that indicates whether or not the control should bedisabled. Default is false

HRef The URL target of the link

id A unique id for the control

InnerHtml Sets or returns the content between the opening and closing tags of the HTML element. Special characters are not automatically convertedto HTML entities

InnerText Sets or returns all text between the opening and closing tags of theHTML element. Special characters are automatically converted to HTMLentities

Name The name of the anchorOnServerClick The name of the function to be executed when the link is clicked

runat Specifies that the control is a server control. Must be set to "server"

Style Sets or returns the CSS properties that are applied to the control

TagName Returns the element tag name

Target The target window to open

Title A title to be displayed by the browser (like the alt attribute of the imgelement)

Visible A Boolean value that indicates whether or not the control should bevisible

Example

HTMLAnchor

ASPX Source:

Sub Page_Load

link1.HRef="http://www.w3schools.com"link1.Target="_blank"

link1.Title="W3Schools"

link2.HRef="http://www.microsoft.com"

link2.Target="_blank"

link2.Title="Microsoft"


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End Sub

Visit W3Schools!
Visit Microsoft!

Output Result:

Visit W3Schools!Visit Microsoft

In this example we declare two HtmlAnchor controls in an .aspx file (remember to embed thecontrol inside an HtmlForm control). Then we modify the URL, target, and title of the HtmlAnchorcontrols in an event handler (an event handler is a subroutine that executes code for a givenevent). The Page_Load event is one of many events that ASP .NET understands.

ASP.NET HtmlButton Control


The HtmlButton control is used to control a element. In HTML, the element isused to create a push button.

Properties







OnServerClick The name of the function to be executed when the button is clickedrunat Specifies that the control is a server control. Must be set to "server"




Example

HTMLButton

ASPX Source:


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Sub button1(Source As Object, e As EventArgs)p1.InnerHtml="You clicked the blue button!"

End Sub

Sub button2(Source As Object, e As EventArgs)p1.InnerHtml="You clicked the pink button!"

End Sub

Blue button!

Pink button!

Output Result:

!!

In this example we declare two HtmlButton controls in an .aspx file (remember to embed thecontrol inside an HtmlForm control). Next, we write an event handler that specifies what to happenwhen a button is clicked.

ASP.NET HtmlForm Control


The HtmlForm control is used to control a element. In HTML, the element is used

to create a form.

Note: All HTML server controls must be within the HtmlForm control!

Note: You can only have one HtmlForm control on a single page!

Properties


Action A URL that defines where to send the data when the form is submitted.

Note: This attribute is always set to the URL of the page itself!


Blue button Pink Button


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EncType The mime type used to encode the content of the form



InnerText Sets or returns all text between the opening and closing tags of the

HTML element. Special characters are automatically converted to HTMLentities

Method How the form posts data to the server. Legal values are: "post" and"get". Default is "post"

Name The name of the form




Target The target window to load the URL


Example

HTMLForm

ASPX Source:Sub submit(sender As Object, e as EventArgs)

if name.value"" thenp1.InnerHtml="Welcome " & name.value & "!"

end ifEnd Sub

Enter your name:

Output Result:

Enter your name:

Submit

In this example we declare one HtmlInputText controls, one HtmlInputButton control, and oneHtmlGeneric control in an .aspx file (remember to embed the controls inside an HtmlForm control).When the submit button is triggered, the submit subroutine is executed. The submit subroutinewrites a welcome message to the p element.


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ASP.NET HtmlGeneric Control


The HtmlGeneric control is used to control other HTML element not specified by a specific HTMLserver control, like , , , ,

, etc.

Properties






InnerText Sets or returns all text between the opening and closing tags of the

HTML element. Special characters are automatically converted to HTMLentities





Example

HTMLGeneric

ASPX Source:

Sub submit(sender As Object, e as EventArgs)

if name.value"" thenp1.InnerHtml="Welcome " & name.value & "!"

end ifEnd Sub

Enter your name:

Output Result:

Enter your name:


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Submit

In this example we declare one HtmlInputText controls, one HtmlInputButton control, and oneHtmlGeneric control (the

tag) in an .aspx file (remember to embed the controls inside anHtmlForm control). When the submit button is triggered, the submit subroutine is executed. Thesubmit subroutine writes a welcome message to the p element.

ASP.NET HtmlImage Control


The HtmlImage control is used to control an element. In HTML, the element is usedto display an image.

Properties


Align How to align the image according to surrounding elements. Legalvalues are:

top

middle

bottom

left

right

Alt A short description of the image


Border The width of the borders around the image


Height The height of the image



Src The URL of the image to display




Width The width of the image

Example

HTMLImage

ASPX Source:

Sub Page_Load(Sender As Object,E As EventArgs)

image1.Src="smiley.gif"image1.Alt="Smiley"

image1.Border="3"End Sub


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Output Result:

In this example we declare an HtmlImage control in an .aspx file (remember to embed the controlinside an HtmlForm control). Then we modify the src, alt and border properties of the HtmlImagecontrol in an event handler (an event handler is a subroutine that executes code for a given event).The Page_Load event is one of many events that ASP .NET understands:

HTMLImage

ASPX Source:

Sub choose_image(Sender As Object, e As EventArgs)

image1.Src = select1.ValueEnd Sub

Smiley

AngryStickman

Output Result

Display image

In this example we declare an HtmlImage and an HTMLSelect control in an .aspx file (remember to

embed the controls inside an HtmlForm control). Then we modify the src property of the HtmlImage


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control based on user choices. The value selected in the HtmlSelect control determines which imageto display.

ASP.NET HtmlInputButton Control


The HtmlInputButton control is used to control , , and elements. In HTML, these elements are used to create a command button, asubmit button, and a reset button.

Properties




id A unique id for the element

Name The name of the element

OnServerClick The name of the function to be executed when the button is clicked

runat Specifies that the element is a server control. Must be set to "server"


TagName Returns the element tag nameType The type of the element

Value The value of the element


Example

HTMLInputbutton

In this example we declare one HtmlInputText controls, one HtmlInputButton control, and oneHtmlGeneric control in an .aspx file (remember to embed the controls inside an HtmlForm control).

When the submit button is triggered, the submit subroutine is executed. The submit subroutinewrites a welcome message to the p element.

ASP.NET HtmlInputCheckBox Control


The HtmlInputCheckBox control is used to control an element. In HTML,this element is used to create a checkbox.

Properties and Events



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Checked A Boolean value that specifies whether or not the element is to bechecked







Type The type of the element



Event Description

ServerChange Occurs when the state of the control has changed

Example

HTMLInputCheckbox

ASPX Source:

Sub submit(Source As Object, e As EventArgs)

if red.Checked=True thenp1.InnerHtml="You prefer red!"

elsep1.InnerHtml="You prefer blue!"

end ifred.checked=false

blue.checked=falseEnd Sub

What color do you prefer?

Red

Blue

Output Result:

What color do you prefer?

Red

Blue


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In this example we declare two HtmlInputCheckBox controls, one HtmlInputButton control, and oneHtmlGeneric in an .aspx file (remember to embed the controls inside an HtmlForm control). Whenthe submit button is triggered, the submit subroutine is executed. The submit subroutine mayrespond in two ways: if the "red" checkbox is checked, the server sends the message "You preferred!" to the p element. If the "blue" checkbox is checked, the server sends the message "You preferblue!" to the p element.

ASP.NET HtmlInputFile ControlDefinition and Usage

The HtmlInputFile control is used to control an element. In HTML, this elementis used to upload a file to the server.

Properties


Accept List of acceptable MIME types


Disabled A Boolean value that indicates whether or not the control should be

disabled. Default is falseid A unique id for the element

MaxLength The maximum number of characters allowed in this element


PostedFile Gets access to the posted file


Size The width of the element





Visible A Boolean value that indicates whether or not the control should be

visible

Example

In the following example we declare one HtmlInputFile control, one HtmlInputButton control, andthree HtmlGeneric controls in an .aspx file (remember to embed the controls inside an HtmlFormcontrol). When the submit button is triggered, the submit subroutine is executed. The file name andfile type are displayed on the page, while the file itself is uploaded to the c directory on the server:

Sub submit(Sender as Object, e as EventArgs)fname.InnerHtml=MyFile.PostedFile.FileNameclength.InnerHtml=MyFile.PostedFile.ContentLength

MyFile.PostedFile.SaveAs("c:\uploadfile.txt")End Sub

Select file to upload to server:


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FileName:
ContentLength: bytes

ASP.NET HtmlInputHidden Control


The HtmlInputHidden control is used to control an element. In HTML, thiselement is used to create a hidden input field.

Properties and Events




id A unique id for the element






Value The value of the hidden field


Event DescriptionServerChange When the content of the element has changed

Example

HTMLInputHidden

ASPX Source:

Sub submit(Source As Object, e As EventArgs)hidden1.Value=string1.Value

p1.InnerHtml="Hidden value= " + hidden1.Value

End Sub

Enter some text:


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Output Result:

Enter some text:Submit

In this example we declare one HtmlInputHidden control, one HtmlInputText control, one

HtmlInputButton control, and one HtmlGeneric control in an .aspx file (remember to embed thecontrols inside an HtmlForm control). When the submit button is triggered, the submit subroutine isexecuted. The submit subroutine sets the value of the hidden field equal to value of the input fieldand then displays the value of the hidden field in the p element.

ASP.NET HtmlInputImage Control


The HtmlInputImage control is used to control an element. In HTML, thiselement is used to create an input button using an image, instead of a regular push-style button.

Properties and EventsProperty Description

Align The alignment of the image

Alt An alternate text to display for the image


Border The width of the borders around the element




OnServerClick The name of the function to be executed when the image is clicked


Src The source of the image






Example

HTMLInputImage

ASPX Source:

Sub button1(Source As Object, e As ImageClickEventArgs)

p1.InnerHtml="You clicked the smiley button!"

End SubSub button2(Source As Object, e As ImageClickEventArgs)

p1.InnerHtml="You clicked the angry button!"

End Sub


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Click on one of the images:

Output Result:

Click on one of the images:

In this example we declare two HtmlInputImage controls and one HtmlGeneric control in an .aspxfile (remember to embed the controls inside an HtmlForm control). If the user clicks on the firstimage, the button1 subroutine is executed. This subroutine sends the message "You clicked thesmiley button!" to the p element. If the user clicks on the second image, the button2 subroutine isexecuted. This subroutine sends the message "You clicked the angry button!" to the p element.

ASP.NET HtmlInputRadioButton Control


The HtmlInputRadioButton control is used to control an element. In HTML,this element is used to create a radiobutton.

Properties



Checked A Boolean value that specifies whether or not the element is to beselected

Disabled A Boolean value that indicates whether or not the control should be

disabled. Default is falseid A unique id for the element


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Name The name of the radio button group






Visible A Boolean value that indicates whether or not the control should be

visible

Example

HTMLInputRadiobutton

ASPX Source:

Sub submit(Source As Object, e As EventArgs)

if r1.Checked=True then

p1.InnerHtml="Your favorite color is red"else

if r2.Checked=True thenp1.InnerHtml="Your favorite color is green"

elseif r3.Checked=True then

p1.InnerHtml="Your favorite color is blue"end if

end ifend if

End Sub

Select your favorite color:

Red

Green

Blue

Output Result:

Select your favorite color:

Red

Green


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Enter your name:

Output Result:

Enter your name:

Submit

In this example we declare one HtmlInputText controls, one HtmlInputButton control, and oneHtmlGeneric control in an .aspx file (remember to embed the controls inside an HtmlForm control).When the submit button is triggered, the submit subroutine is executed. The submit subroutinewrites a welcome message to the p element.

ASP.NET HtmlSelect Control


The HtmlSelect control is used to control a element. In HTML, the element isused to create a drop-down list.

Properties



DataMember A name of a data table to use

DataSource A data source to use

DataTextField A field in the data source to be displayed in the drop-down list

DataValueField A field in the data source that specifies the value of each selectableitem in the drop-down list





Items The list of items in the drop-down list

Multiple Whether multiple items can be selected at a time

OnServerChange The name of the function to be executed when the selected item haschanged


SelectedIndex The index of the currently selected item

Size The number of visible items in the drop-down list



Value The value of the currently selected item



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Example

HTMLSelect

ASPX Source:

Sub choose_image(Sender As Object, e As EventArgs)

image1.Src = select1.ValueEnd Sub

SmileyAngry

Stickman

Output Result:

Display image

In this example we declare an HtmlImage and an HTMLSelect control in an .aspx file (remember toembed the controls inside an HtmlForm control). Then we modify the src property of the HtmlImagecontrol based on user choices. The value selected in the HtmlSelect control determines which imageto display.

ASP.NET HtmlTable Control


The HtmlTable control is used to control a element. In HTML, the element is usedto create a table.

Properties


Align Specifies the alignment of the table


BGColor Specifies the background color of the table

Border Specifies the width of the borders


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Tip: Set border="0" to display tables with no borders!

BorderColor Specifies the color of the borders

CellPadding Specifies the space between the cell walls and contents

CellSpacing Specifies the space between cells


Height Specifies the height of the tableid A unique id for the control



Rows Returns an HtmlRowCollection object which represents all rows in thetable





Width Specifies the width of the table

Example

HTMLTable

ASPX Source:


Dim row,numrows,numcells,j,irow=0numrows=cint(rows1.Value)

numcells=cint(cells1.Value)for j=1 to numrows

Dim r As New HtmlTableRow()row=row+1

for i=1 to numcellsDim c As New HtmlTableCell()

c.Controls.Add(New LiteralControl("row " & j & ", cell " & i))

r.Cells.Add(c)next

t1.Rows.Add(r)

t1.Visible=truenext

End Sub

Table rows:

1

23


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Table cells:

1

23

Output Result:

Table rows:

Table cells:

Display Table

In this example we declare two HtmlSelect controls, one HtmlInputButton control, and oneHtmlTable control in an .aspx file (remember to embed the controls inside an HtmlForm control).The user may choose number of cells and rows. When the submit button is triggered, the submitsubroutine is executed. The submit subroutine generates the table based on what the user didinput.

HTMLTable

ASPX Source:

Sub submit(sender As Object, e As EventArgs)dim i,j

table1.BGColor="yellow"table1.BorderColor="red"

for i=0 To table1.Rows.Count-1for j=0 To table1.Rows(i).Cells.Count-1

table1.Rows(i).Cells(j).InnerHtml="Row " & inext

nextEnd Sub

Cell 1Cell 2


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Example

HTMLTable

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