The operation is not valid due to the current state of the object

Thursday, August 16. 2007

The operation is not valid due to the current state of the object

I've recently become re-united with an old friend -- that's right, I'm back to working with SharePoint. Since this time I'm armed with a little bit more time and resources, I'm hoping it will be less painful than it was last time.

The first major snag I've hit so far is the issue of how to deploy custom web services on the SharePoint server. The docs from the SDK recommend the approach of adding the web service to SharePoint so that it can be accessed from _vti_bin/servicename.asmx. From my relatively inexperienced point of view, this is good for a number of reasons, the main one being that the custom web service runs as part of SharePoint, and things like permissions, privileges and access control seem to be handled for you. Great.

There's a catch though. The main one is that you need to dump the WS assembly into the server's GAC. There are other pains in getting the disco and wsdl files set up for your custom WS, but the SDK walks you through those.

An alternative to the recommended approach is to deploy your custom web service to an IIS web site separate from SharePoint (obviously, this is still on the SharePoint server). This seems to opens up a whole new can of worms with privileges. The fun begins.

The problem I ran into was an "The operation is not valid due to the current state of the object" exception being thrown when adding files or updating items. Google saved the day rather quickly -- http://howtocode.blogspot.com/2007_06_01_archive.html.

QUOTE:

You must not call the SPListItem.Update inside the RunWithElevatedPrivileges block. Instead you should only instantiate the SPSite or SPWeb there and call Update afterwards...

The strange thing is that this seemed to work last year, when I was bashing my head against the WSS Beta TR2. I guess things change...

Posted by Misha in Development at 17:39 | Comments (2) | Trackbacks (0)

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My joy was somewhat short-lived. I soon realised that documents uploaded to libraries using the custom web service I created were put there on behalf of the `System' account rather than whomever was actually responsible for getting the file there.

After asking around, I've finally found the true root of the problem I was having -- the authentication model for the custom web service. It was configured to use anonymous authentication. Once set to use integrated windows authentication, everything worked fine, and I no longer needed to work with elevated privileges.

#1 Misha (Homepage) on 2007-08-21 15:06 (Reply)

you sir, have saved me a lot of time. thanks

#2 jim hudson on 2008-07-26 05:44 (Reply)

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