solution for RPC_E_ATTEMPTED_MULTITHREAD error caused by SPRequestContext caching SPSites?

Question

I'm developing a solution for SharePoint 2007, and I'm using SPSecurity.RunWithElevatedPrivileges a lot, passing in UserToken of the SystemAccount.

After reading http://hristopavlov.wordpress.com/2009/01/19/understanding-sharepoint-sprequest/ I finally began to understand why I get these System.Runtime.InteropServices.COMException (0x80010102): Attempted to make calls on more than one thread in single threaded mode. (Exception from HRESULT: 0x80010102 (RPC_E_ATTEMPTED_MULTITHREAD)) errors, but there seems to be no solution - "known issue in the product"

The article is more then a year old. I wasn't able to find anything more recent and helpful, but I was hoping maybe someone else has?

My code goes like this

  SPSecurity.RunWithElevatedPrivileges(delegate()
  {
    using (SPSite elevatedSite = new SPSite(web.Site.ID, web.Site.SystemAccount.UserToken))
    {
      using (SPWeb elevatedWeb = elevatedSite.OpenWeb(web.ID))
      {
        // some operations on lists and items obtained through elevatedWeb
      }
    }
  }

The errors come up wherever such an elevated code is used, and more often when there are more users who use these functionalities, so I guess perhaps the elevated SPSite is getting cached and reused.

Is there any way to solve this? If my understanding is correct, how to make Sharepoint forget about the cached SPSites, and use a fresh one instead?

Thanks

Answer 1

Solved it myself, after finally understanding what I'm actually doing there - by using for example new SPSite(web.Site.ID, I'm actually making the delegate, which seems to be on a new thread, reach into web, which is on the original thread

So the answer is: you have put all the data you'll need (like various IDs, SystemAccount.UserToken etc.) into variables before running the delegate, and don't access any objects with associated SPRequest (webs, lists, items, users...) from inside the delegate. And, of course, the same holds for data that goes out of the delegate - you can return web ID, list ID and item ID, but you better not return SPListItem.