Web Form FundamentalsWeb Form FundamentalsMacDonald Ch. 5MacDonald Ch. 5

MIS 324

Professor SandvigProfessor Sandvig

OutlineOutline

Web FormsWeb Forms– Three sectionsThree sections

Order of ExecutionOrder of Execution

ViewstateViewstate

Web FormsWeb Forms

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

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 Cycle overview (for the curious)Page Life Cycle overview (for the curious)

Examples: Examples: – PostBack.aspx handoutPostBack.aspx 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)

Web Form SummaryWeb Form Summary

Designed to separate code and Designed to separate code and presentationpresentation

Event drivenEvent driven– User eventsUser events– Page eventsPage events

Granular control of event handlingGranular control of event handling

Viewstate provides convenienceViewstate provides convenience