How to get the original query string in an event receiver when dialogs are enabled

Question

I have scenario where I am adding a document to a document library which has an external data column on it. My goal for this column is to have it automatically populated with an appropriate value based on original query string to the page. The general
idea is that I am on a custom page that has various webparts on it including a view of my document library that is context sensative based on the query string, and I want to use that context sensitivity not just to filter the list but also when adding documents.
I have been searching around for solutions to this problem all day and have gotten this far:
I have an event receiver attached to my document library that handles the ItemAdded event syncronously (as such I have the new list item available to me). In that event receiver I am able to set the column values as required. Where I am stuck is on getting
the value from the query string that I need to actually set as the column value.
Based on:
http://social.technet.microsoft.com/Forums/en-US/sharepoint2010programming/thread/8cfcb299-9a55-4139-86ec-0b53b2922a54 and several similar articles/posts I have been able to get the original source Url with the query string I want via the following
code in my event receiver:
private HttpContext context;
public EventReceiver1()
context = HttpContext.Current;
public override void ItemAdded(SPItemEventProperties properties)
var originalQueryString = context.Request.QueryString["Source"];
// Parse the query string and use the value ...
The problem is that this solution breaks down if the dialogs are turned on under the advanced settings for the list. The reason the solution fails is because the "Source" query string parameter goes away and is replaced by "IsDlg" set to a value of "1".
Does anyone know how to get past this hurdle? Any help would be greatly appreciated.

Answer 1

Hi Stuart,
The reason I'm looking for "Source" in the query string is because that is something I found to be reliable when the Dialogs are turned off. I've dug around pretty deep in the Request object to see if anything had the data I was looking for and unfortunately
it doesn't appear to be there. The
context.Request.QUeryString.ToString()
returns a rather simple one of:
List=%7b43ECDCB0-8440-4652-B067-AA20481779D7%7d&RootFolder=&IsDlg=1
and the
context.Request.UrlReferrer.Query.ToString()
has the same value.
I suspect this is due to the dual step process that takes place in adding an item to a document library where the first modal popup (which I suspect likely has the information I need) gives you the opportunity to browse to your file and then the second
dialog (maybe this is getting brought up as a result of another request which is now referring back to the original request that brought up the first dialog?) where you edit your properties.
Thanks for the try though, if you've got anything else I'd love to hear it.