Web Form FundamentalsWeb Form Fundamentals

OutlineOutline

Web FormsWeb Forms– Three sectionsThree sections

Order of ExecutionOrder of Execution

ViewstateViewstate

Web FormsWeb Forms

Three SectionsThree Sections1.1. Page DirectivesPage Directives

2.2. Code Declaration BlockCode Declaration Block

3.3. Code Render BlockCode Render Block

1. Page Directives1. Page Directives

Set page propertiesSet page properties– Language, debugging, tracing, …Language, debugging, tracing, …

Import additional class librariesImport additional class libraries– Common ones imported automaticallyCommon ones imported automatically

– Additional:Additional:Database access, data manipulation, web Database access, data manipulation, web services, drawing, communication…services, drawing, communication…

2. Code Declaration Blocks2. Code Declaration Blocks

Syntax:Syntax:<script runat=“server”><script runat=“server”>

//Server-side code here…//Server-side code here…

</script></script>

Locate:Locate:– Anywhere on page Anywhere on page usually at top usually at top– Another file Another file Code-Behind Code-Behind

3. Code Render Block3. Code Render Block

Contain:Contain:– HTMLHTML– TextText– Server ControlsServer Controls

Typically located below Code blockTypically located below Code block– Location does not affect outputLocation does not affect output

Code Render BlockCode Render Block

Can include ASP/PHP style tagsCan include ASP/PHP style tags– Syntax: <% =strLastName %>Syntax: <% =strLastName %>

Not used much in ASP.NETNot used much in ASP.NET

OutlineOutline

Web FormsWeb Forms– Three sectionsThree sections

Order of ExecutionOrder of Execution

ViewstateViewstate

Order of ExecutionOrder of Execution .NET is event driven.NET is event driven

– Events include:Events include: Page loadPage load Button clickButton click checkbox checkedcheckbox checked textbox text changedtextbox text changed etc.etc.

We write handlers (methods) to handle eventsWe write handlers (methods) to handle events Events fired in sequenceEvents fired in sequence Page Life CyclePage Life Cycle overview (for the curious) overview (for the curious)

Examples: Examples: – PostBack.aspxPostBack.aspx handout handout

OutlineOutline

Web FormsWeb Forms– Three sectionsThree sections

Order of ExecutionOrder of Execution

ViewstateViewstate

ViewStateViewState

Saves control dataSaves control data– Encoded in hidden form fieldEncoded in hidden form field

Benefit: convenienceBenefit: convenienceDisadvantageDisadvantage– Processing overheadProcessing overhead– BandwidthBandwidth– NovusHRNovusHR

Turn off with:Turn off with:– EnableViewState=“false”EnableViewState=“false”

Individual controlsIndividual controlsPage (in page directive)Page (in page directive)

SummarySummary

.NET Framework.NET Framework– Like a huge Lego setLike a huge Lego set

+5,000 types of pieces+5,000 types of pieces

– Mix and match pieces to build most anythingMix and match pieces to build most anything

Easily extendedEasily extended– Add new classesAdd new classes

Support for many languages & platformsSupport for many languages & platforms