AuctionConstructor.com

A free utility for making professional auction ads for use on sites such as eBay - Very simple to use and great looking html and css final product

Decided to make this a while back because I sell a sorts of stuff on eBay and I got tired of writing html for each and every ad. Once I came up with the concept, I figured why not allow other people to use it for free?

It has gone through a couple iterations; changed from ColdFusion to asp.net, and is constanty being updated and improved.

Pease check it out and give it a try for yourself!

 

 

 

apparently viewstate variables time out?

a peculiar error that didn't make much sense to me...

For the past couple years, I have kept up a website that makes auction ads for sites like eBay if the user simply fills in a few blanks - the website is AuctionConstructor.com (it's free, check it out). Now this isn't just a shameless plug for my awesome and useful website... I was having the most annoying problem with it for the longest time.

If the user filled in the blanks within a decent amount of time, say 2-3 minutes, everything would work just fine. BUT, if the user took a long time to fill them out, they would get this awesome (read: incredibly annoying) error:
Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.
As far as I always knew, ViewState variables in ASP.NET did not timeout? Not to mention that I am not being hosted on a cluster. After digging and digging on forums all over the place I found this: http://connect.microsoft.com/VisualStudio/ feedback/ViewFeedback.aspx?FeedbackID=101988 and it appears that:
It appears because GridView using DataKeyNames requires ViewState to be encrypted. And when ViewState is encrypted, Page adds <input type="hidden" name="__VIEWSTATEENCRYPTED" id="__VIEWSTATEENCRYPTED" value="" /> field just before closing of the <form> tag. But this hidden field might not bet yet rendered to the browser with long-running pages, and if you make a postback before it "gets down", browser initiates postback without this field (in form post collection)

End result is that if this field is omitted on postback, Page doesn't "know" that viewstate is encrypted and causes the prementioned Exception. E.g Page expects to be fully-loaded before you can make a postback. And by the way similar problem is with event validation since __EVENTVALIDATION field is also rendered on the end of the form.
And since that is not completely my problem considering this happens prior to the page loading, where my error happened much, much later than that I then made the assumption that the ViewState tiems out therefore the same thing happens where the page doesn't "know" that viewstate is encrypted and causes the error.

So... I after attempting a few different solutions, the final answer to my problem (and over a years worth of errors) is the following change to your web.config file:
<pages enableViewStateMac="false" enableEventValidation="false" viewStateEncryptionMode ="Never" >
Keep in mind, that this could cause some security issues, but I wouldn't see that being a huge problem - basically, your program will not be sure that it is the same computer posting back that opened the page int the first place, but in the case of my site, this is not a concern as I am not dealing with any sensitive information. I would think this error wouldn't rear it's ugly head as often on a page where there is sensitive information, as it usually does not take a huge amount of time to fill out that information.

*This is on a .NET 2.0 server, and hopefully 3.5 has it fixed (my host upgrades February 2008) as it is a recognized problem by Microsoft.
Another great link: http://forums.asp.net/p/955145/1173230.aspx#1173230

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