After spending allot of years in the Classic ASP world. I am a little over half way through a beginnning ASP.NET book using VS 2010.

Over the years I have always tried to write clean neat code. Within reason trying to write as few lines as possible to get my outcome. Nice short meaningful ID/Name/Value strings etc...

I can not beleive the state of the code Visual Studio creates after viewing the source in the browser. Even a fairly simple page. I mean what on earth is this neccesary for:

<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUKMTk4NTYxMTcyMw9kFgJmD2QWAgIDD2QWCAIFDzwrAA0 BAA8WAh4HVmlzaWJsZWhkZAIJDzwrAAkCAA8WCB4NTmV2ZXJFe HBhbmRlZGQeC18hRGF0YUJvdW5kZx4MU2VsZWN0ZWROb2RlZB4 JTGFzdEluZGV4AghkCBQrAAUFDzA6MCwwOjEsMDoyLDA6MxQrA AIWDh4EVGV4dAUESG9tZR4FVmFsdWUFBEhvbWUeC05hdmlnYXR lVXJsBQ0vRGVmYXVsdC5hc3B4HgdUb29sVGlwBRJHbyB0byB0a GUgaG9tZXBhZ2UeCERhdGFQYXRoBQ0vZGVmYXVsdC5hc3B4Hgl EYXRhQm91bmRnHghFeHBhbmRlZGdkFCsAAhYSHwYFB1Jldmlld 3MfCmcfBQUHUmV2aWV3cx8HBRUvUmV2aWV3cy9EZWZhdWx0LmF zcHgeCVBvcHVsYXRlZGcfC2cfCAUeUmV2aWV3cyBwdWJsaXNoZ WQgb24gdGhpcyBzaXRlHwkFFS9yZXZpZXdzL2RlZmF1bHQuYXN weB4QUG9wdWxhdGVPbkRlbWFuZGgUKwADBQcwOjAsMDoxFCsAA hYOHwUFCEJ5IEdlbnJlHwYFCEJ5IEdlbnJlHwcFGC9SZXZpZXd zL0FsbEJ5R2VucmUuYXNweB8IBRxBbGwgUmV2aWV3cyBHcm91c GVkIGJ5IEdlbnJlHwkFGC9yZXZpZXdzL2FsbGJ5Z2VucmUuYXN weB8KZx8LZ2QUKwACFg4fBQULQWxsIFJldmlld3MfBgULQWxsI FJldmlld3MfBwURL1Jldmlld3MvQWxsLmFzcHgfCAULQWxsIFJ ldmlld3MfCQURL3Jldmlld3MvYWxsLmFzcHgfCmcfC2dkFCsAA hYSHwYFBUFib3V0HwpnHwUFBUFib3V0HwcFEy9BYm91dC9EZWZ hdWx0LmFzcHgfDGcfC2cfCAUPQWJvdXQgdGhpcyBTaXRlHwkFE y9hYm91dC9kZWZhdWx0LmFzcHgfDWgUKwADBQcwOjAsMDoxFCs AAhYOHwUFCkNvbnRhY3QgVXMfBgUKQ29udGFjdCBVcx8HBRMvQ WJvdXQvQ29udGFjdC5hc3B4HwgFCkNvbnRhY3QgVXMfCQUTL2F ib3V0L2NvbnRhY3QuYXNweB8KZx8LZ2QUKwACFg4fBQUIQWJvd XQgVXMfBgUIQWJvdXQgVXMfBwUTL0Fib3V0L0Fib3V0VXMuYXN weB8IBQhBYm91dCBVcx8JBRMvYWJvdXQvYWJvdXR1cy5hc3B4H wpnHwtnZBQrAAIWDh8FBQVMb2dpbh8GBQVMb2dpbh8HBQsvTG9 naW4uYXNweB8IBRdMb2cgaW4gdG8gdGhpcyB3ZWIgc2l0ZR8JB QsvbG9naW4uYXNweB8KZx8LZ2RkAg8PEGRkFgECAWQCEQ9kFgR mDw8WAh8AZ2QWAgIBDxYCHgRocmVmBRNodHRwOi8vcDJwLndyb 3guY29tZAICDw8WAh8AaGRkGAEFHl9fQ29udHJvbHNSZXF1aXJ lUG9zdEJhY2tLZXlfXxYBBQ9jdGwwMCRUcmVlVmlldzEEOr7fK NOD7mtal8YtuOjZpKmVnyaZXJcQP4aMmint6A==" />

OMG Im in dis belief! Is this just how it is in the .net world? I know classic ASP is dying a slow death and this .net world is where things have, and are going. Gee what a mess to walk into....

__________________
Wind is your friend
Matt

ASP.NET uses __VIEWSTATE in place of using Session variables, to keep track of what is going on in the server vs. what is going on in the browser. Basically, __VIEWSTATE is an encrypted form of the info that ASP.NET needs to reconstruct the server code to the same state each time.

For example, you may have noticed that ASP.NET is aware of *BOTH* the text and value of the <option>s of a <select>. Yes HTML will always send back *only* the value= of an <option>. So ASP.NET "connects" those value= values to the text using this __VIEWSTATE info. Similar stuff abounds. It's really all the same that you *could* do in classic ASP using session variables (or your own hidden fields or tricks with value=) but it's all done for you. Really, it's very little overhead in the browser (much smaller than, say, even the smallest <img> you might display!) for a lot of gain in functionality.

Form my very limited .net experience (page 432 of Imar's Beginning .net 3.5) I figured this was where that crazy hiden form field came from. I guess my little rant was out of suprize coming from someone who is used to only seeing code that is intentionaly put there. Thank you for your time

__________________
Wind is your friend
Matt

It's really just a trade-off. MS could have chosen to put that same info into Session variables (or equivalent) and stored it all on the server. For most low-volume sites, that's probably a preferable answer. But for really high-volume sites, keeping stuff *off* the server is a good idea.

I'm not really defending their choice, per se. Just explaining it. I know I have occasions when using classic ASP when I've needed to "persist" a *LOT* of information, and I've used session variables because the sites were relatively low volume. But I've always been aware that session variables can indeed be "poison" to a high volume site.

I don't think that's accurate, is it? Doesn't it know the value and the text because it recreates the control tree at the server and gets a selected value from the client?

ASP.NET does use ViewState for similar stuff though, like the text in a TextBox before it gets sent to the browser. That way, when users enter a different text, the TextChanged event can be fired. ViewState is also used heavily by the data controls to store data, primary keys and so on.

In the book you'll find a number of tips on minimizing the impact of ViewState by turning it off where possible. ASP.NET 4 has greatly changed the ability to fine-tune this (and thus minimize it even further) with the introduction of the ViewStateMode attribute: http://www.mostlylucid.net/archive/2009/01/28/1312.aspx

Cheers,

Imar

__________________
Imar Spaanjaars
http://Imar.Spaanjaars.Com
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Author of Beginning ASP.NET 4.5 : in C# and VB, Beginning ASP.NET Web Pages with WebMatrix
and Beginning ASP.NET 4 : in C# and VB.
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