Page Life Cycle And ViewState

Presenter: Vijay Goyal, Mindfire SolutionsSkype: mfsi_vijaygDate: 30/09/2013

Conferrer: Vijay Goyal, Mindfire Solutions

Agenda Of The Seminar

- Pre Page Life Cyle (Asp.Net Inside IIS)- What on Earth is ViewState?- The different (Important) stages of Life Cycle- Where ViewState comes into the picture?- Dynamically created control- Deal with the burden of ViewState on the page - Some Demo...with some more Demo

This is not an IIS course

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The Two Important Services

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The ProcessRequest()- After all the registered Modules are executed. The page is ready to be served.

- For this IIS uses the handler's mapping, to map the request to the appropriate handler.

- ProcessRequest() method is executed and Page Life Cycle begins

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The Page Life Cycle Begins..

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Formation Of Control Heirarchy

- Request to an aspx page is served by a compiled class“C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files”

- Initializes the page's control hierarchy

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Formation Of Control Heirarchy

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But What's ViewState??

- Its a misunderstood topic- An object of Statebag class- Stores changes done programatically- SelectedIndex / PageIndex not stored- A property of System.Web.UI.Controls- A key/value pair indexer.- Serialized to _VIEWSTATE hidden field- ViewState is a hungry beast.

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Initialization

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- PreInit (Entry point, Non Recursive)

- Init (Tracking of Viewstate is not enabled

/ Enabled for child controls, Recursive)

- InitComplete (Viewstate tracking is turned on, Non Recursive)

- SaveViewState()

- Page.TrackViewState()

Load ViewState/Page Data

- Invoked only on Postbacks

- LoadControlState (Introduced in Asp.Net 2.0,gridview page control, SaveControlState()l)

- LoadViewState (Page and controls restored,SaveViewState())

- LoadPostData (Controls implement IpostBackDataHandler,Selected value in dropdown, checkbox, Textbox)

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Loading the Page...

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- PreLoad (Non Recursive, End of Viewstate data load)

- Load (Top down approach, Previous State is fully loaded)

- RaisePostDataChangeEvent (Controls implement IpostBackDataHandler, TextChanged/SelectedIndexChanged)

- RaisePostBackEvent (Controls implement IpostBackDataHandler,click event)

- LoadComplete (Page only)

Page Rendering- PreRender (Recursive, Last update before the page is rendered)

- PreRenderComplete (last event before the page's view state is saved.)

- SaveControlState

- SaveViewState (Control/Viewstate data are serialized to _VIEWSTATE)

- Render and Unload (Renders the html to Client, Final Cleanup,closing db, finishing up logging..etc)

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A Scenario

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Dynamically Added Controls

- They are not part of the compiled class

- Should be added in every page execution

- Plays catchup (go thru all the page life cycle events of their own, Before Page Render)

- Recommended to call in PreInit or Init, before tracking is enabled

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Abbreviating ViewState

- Disable ViewState

- System.Web.UI.LosFormatter (Limited Object Serialization)

- Compress/Decompress (SavePageStateToPersistenceMedium, LoadPageStateFromPersistenceMedium)

- Store in an external file (Use SessionId/ GUID)

- Others... (Flesk.ViewStateOptimizer)

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Security??- ViewState Decoder (a nice tool created by Fritz Onion).

- EnableViewStateMac

- ViewStateEncryptionMode (Always/Auto , control calls Page.RegisterRequiresViewStateEncryption() /Never)

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Prevent Tampering

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Prevent Tampering

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Here and there...

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Machine.Config file - <machineKey validation="SHA1" validationKey="F3690E7A3143C185AB1089616A8B4D81FD55DD7A69EEAA3B32A6AE813ECEECD28DEA66A23BEE42193729BD48595EBAFE2C2E765BE77E006330BC3B1392D7C73F" DecryptionKey =” ” />

- Local Security Authority Subsystem Service component

- References http://msdn.microsoft.com/en-us/library/ff649308.aspxhttp://msdn.microsoft.com/en-us/library/ms178472.aspxhttp://pluralsight.com

Conferrer: Vijay Goyal, Mindfire Solutions

Presenter: Vijay Goyal, Mindfire Solutions