additional web server controls

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Chapter 4The Additional WebServer Controls


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2 Additional Server ControlsOverview

This presentation briefly discusses theadditional web server controls


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3 Additional Server ControlsThe Additional Controls

These controls are less frequently usedthan those covered in the previouschapter.

they are still quite useful to know.

The controls covered in this chapter can begrouped into two categories:

those that are container controls

those that are not.


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4 Additional Server ControlsThe Additional Controls

The Panel , Mul t i Vi ewand Vi ew, Wi zar d,and Pl aceHol der controls' basic functionis to act as a container or parent for othercontrols.

These container controls have manypowerful features that make them animportant part of any ASP.NET developersrepertoire.

The other controls covered in this chapter(AdRot at or , Fi l eUpl oad, and Xmlcontrols) are not container controls.

They perform fairly specialized jobs and assuch may not be used nearly as frequentlyas some other controls.


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5 Additional Server ControlsList of the Other Web Server

Controls

Displays a check box for selectedtrue or false values.

Panel

The MultiView control is a container

for groups of View controls.

Mul t i Vi ew,

Vi ew

Displays a push button that posts aWeb form page back to the server.Allows a user to upload a file to theserver. Consists of a text box andBrowse button.

Fi l eUpl oad

Displays an advertisement banner(i.e., a randomly selected imagethat, when clicked, navigates to anew Web page).

AdRot at or


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6 Additional Server ControlsList of the Other Web Server

Controls

Displays an XML file or the results ofan XSLT (Extensible Stylesheet

Language Transformation)transformation.

Xml

Provides a series of interconnectedforms used for collectinginformation incrementally from theuser.

Wi zar d

A container control used fordynamically loading other controls.

Pl aceHol der


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7 Additional Server ControlsPanel Control

The Panel control is a container controlthat can be used as a parent container forplain text, HTML elements, and other webserver controls.

The Panel control is typically used forcreating group behavior, e.g.

creating a unique look for an area on apage

programmatically display and hide groupsof controls.


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8 Additional Server ControlsPanel Control

Panel

Panel

(Hidden)

Panel

(Visible)


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9 Additional Server ControlsMultiView + View

Like the Panel control the Mul t i Vi ewcontrol is a container control for othercontent and controls.

The Mul t i Vi ewcontrol is a container for

groups of Vi ewcontrols. Each of these Vi ewcontrols is also a

container for other controls and HTMLcontent.

They are an easier way to selectivelydisplay and hide groups of controls thanusing multiple Panel controls.

Often no programming is required.


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11 Additional Server ControlsWeb Wizards

Web applications often require some typeof wizard-style interface that leads the userthrough a series of step-by-step forms.

A wizard is thus used to retrieve

information from the user via a series ofdiscrete steps.

each step in the wizard asks the user toenter some subset of information.


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12 Additional Server ControlsWeb Wizard


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In regular Windows applications, wizardstend to be modal in that the user can notdo any other processing while the wizard isactive:

the user can only move forward,backwards, finish, or possibly jump to someother step in the wizard.

As well, Windows-based wizards arepipelines,

i.e., a wizard is a chain of processes inwhich there is only one entrance and wherethe output of each step in the process is theinput to the next step.


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Implementing wizards in web applicationsposes several problems.

A Windows application can strictly controlhow a wizard is launched, and can easily

ensure users start and exit the wizard in theappropriate way.

This is much harder to implement in a webenvironment.

A user could, for instance, bookmark an

intermediate step in the wizard and try toreturn to it at some point in the future.

A web-based wizard must thus be able tomaintain the pipeline nature of the wizardand ensure that the user only ever starts

the wizard at the first step.


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Maintaining state information in a multi-page web wizard can also be tricky.

Since the intent of a wizard is to gatherinformation from the user in a series of

discrete steps, a web wizard needs to beable to pass information gathered inprevious steps onto the next step.

This requires repetitive coding for theretrieval and verification of the previous

steps data. As well, there is typically a great deal of

repetitive code for the handling ofnavigation within the wizard.


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16 Additional Server ControlsWizard Control

The Wi zar d control in ASP.NET 2.0 makesthe process of creating a web wizardsignificantly easier.

This control provides a simpler mechanism

for building steps, adding new steps, orreordering the steps.

The Wi zar d control eliminates the need tomanage the persistence of your data

across pages because the control itselfmaintains state while the user completesthe various steps.


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17 Additional Server ControlsWizard Control

St ep One
Emai l

Passwor d

St ep Two

Shi ppi ng

Ai r Mai l Fed Ex


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18 Additional Server ControlsWizard Styling

You have a great deal of control over theappearance and behavior of the Wi zar dcontrol.


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19 Additional Server ControlsFileUpload Control

The Fi l eUpl oad control provides amechanism for users to send a file fromtheir computer to the server.

The control is rendered in the browser as a

Text Box control and a But t on control.


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20 Additional Server ControlsPlaceHolder Control

The Pl acehol der web server controlenables you to dynamically add servercontrols to a page at run-time.

The Pl acehol der is an empty container

control with no HTML rendering on itsown.

instead, the control renders any childelements it contains.


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21 Additional Server ControlsPlaceHolder Control

There are many situations in which itmight make sense to add a controldynamically at run-time rather thanstatically at design-time.

A portal application, for instance, mayconsist of only a few pages, each containingPl acehol der controls that are loaded withthe appropriate server and user controls atrun-time according to some algorithm or

some content in a database.


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22 Additional Server ControlsAdRotator Control

Displays a randomly selectedadvertisement banner (a graphic image).

The displayed advertisement can changewhenever the page refreshes.

If a user clicks the ad, he or she isredirected to the target URL specified bythe control.

The displayed advertisements can also be

priority weighted; this allows certainadvertisements to be displayed more often.

The control works by readingadvertisement information stored in aseparate data source, which is usually anXML file.


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23 Additional Server ControlsXml Control

The Xml server control can be used todisplay the unformatted contents of anXML document or the result of an XSLTtransformation.


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24 Additional Server ControlsXSLT

An XSLT document is itself an XMLdocument.

It is an XML-based programming languagefor transforming XML documents.

The .NET XSLT parser can thus be used totransform a XML document into an XMLdocument with a different structure, aHTML file, a text file, or almost any othertype of document.


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25 Additional Server ControlsXML Control + XSLT

Xml control in the browser with no XSLT

Xml control using an XSLT file

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