How to stop event handler recursion

I was getting errors into event log when I was trying to update list in which I have written event handler code and again that code was executed from event receiver only, so it goes in loop, sometimes my page becomes very slow.

Solution:

I need to write code which will disabled event firing before when I was trying to update something into same list and then I need to enable event firing after my code.

SAMPLE CODE:

this.DisableEventFiring();

objtem.SystemUpdate(false);

this.EnableEventFiring();

Reference Links:

 

http://www.sharepoint-tips.com/2006/10/preventing-event-handler-recursion.html

Thank you!

How to impersonate user into event receiver class or Access denied error on event receiver

Requirement:

I need to remove user permission from list item based on some specified condition; normal user don’t have rights to remove user level permission, so I need to put my business logic into RunWithElevatedPrivileges delegate into event receiver class, but I was facing some challenges after that also, normal user was getting access denied errors while breaking inheritance of list item into event receiver class.

Solution:

We need to be very careful while writing impersonation code into event receiver, because if we miss one class or object to take reference from current logged in user then code won’t work, in my case – I was taking List Item on current logged in user context, I need to be very specific for taking List Item. Key here is needs to take list item by SPListItem objItem = elevatedWeb.Lists[properties.ListId].GetItemById(properties.ListItem.ID);

 

SAMPLE CODE:

 

SPSecurity.RunWithElevatedPrivileges(delegate()

            {

                using (SPSite elevatedSite = new SPSite(properties.SiteId))

                {

                    using (SPWeb elevatedWeb = elevatedSite.OpenWeb(properties.RelativeWebUrl))

                    {

                        SPListItem objItem = elevatedWeb.Lists[properties.ListId].GetItemById(properties.ListItem.ID);

  objItem.Web.AllowUnsafeUpdates = true;

                                objItem.BreakRoleInheritance(false);

                            objLeaseItem.Web.AllowUnsafeUpdates = true;

}

                    }

                });

Reference Links:

http://social.msdn.microsoft.com/forums/en-US/sharepointdevelopment/thread/f2ccd61a-8828-4c17-8360-20d45d6b9514

http://social.msdn.microsoft.com/Forums/en-US/sharepointdevelopment/thread/c3d2b304-7fcc-40d2-86ce-61d9b21b03d7  

http://boris.gomiunik.net/2009/04/spsecurityrunwithelevatedprivileges-and-access-denied-error-on-event-receiver/  

Good Luck!