Intro to ASP'Net ajax

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Intro to ASP.Net ajax

• Tim Wingfield

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Why AJAX?

• Better User Experience
• Browser standards getting better
• Use XMLHttpRequest
• Javascript
• Update the DOM

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Objectives

• How to get started with ASP.Net AJAX
• The Script Manager
• Using an update panel for partial page rendering
• Javascript callbacks
• AJAX Control Toolkit

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Getting Started

• Download the libraries at http//ajax.asp.net
• Run installation
• In Visual Studio add a new ASP.Net AJAX Enabled
  Web Site

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Script Manager

• ltaspScriptManager ID"ScriptManager1"
  runat"server /gt
• EnablePartialRendering default True
• EnablePageMethods default False
• AsyncPostBackTimeout default 90 seconds
• AsyncPostBackErrorMessage
• Scripts collection
• Services collection

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Update Panel

• ltaspUpdatePanel ID"UpdatePanel1"
  runat"server"gt
• ChildrenAsTriggers default True
• UpdateMode default Always
• RenderMode default Block

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Update Panel Pros and Cons

• Pros
• Quick and Easy
• Makes most ASP.Net controls AJAX enabled out of
  the box
• Cons
• Full page life-cycle every time
• No default user feedback of async postback
• Extra work for error handling

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Update Progress Control

• Add your own images and text
• Attaches to one or more Update Panels

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Page Request Manager

• Sys.WebForms.PageRequestManager.getInstance()
• Manages the partial-page updates of Update Panels
• Partial Page Rendering must be true
• One instance per page

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Page Request Manager Client Events

• initializeRequest
• beginRequest
• pageLoading
• pageLoaded
• endRequest

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Javascript Callbacks

• Use Web Services or Page Methods
• JSON
• Can return full objects

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Callback Pros and Cons

• Pros
• Lightweight and quick
• No page lifecycle involved
• Reuse via web services
• Cons
• Heavy client script
• More difficult debugging

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AJAX Control Toolkit

• Shared source project through Microsoft
• 34 controls at the moment
• Download and copy dll into project to use
• Quickly and easily make a better UX
• Extender available to create your own controls

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Resources

• Microsoft AJAX libraries ajax.asp.net
• Toolkit asp.net/ajax/ajaxcontroltoolkit/
• Scott Guthrie weblogs.asp.net/scottgu/
• Matt Berseth mattberseth.com
• David Hayden davidhayden.com/blog/dave/

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Tim Wingfield

• Email tim_at_timwingfield.com
• Blog blog.timwingfield.com