sharepoint workflow stuck in a loop

Question

I have two sharepoint lists on which I have two custom workflows running automatically on Item added / updated. Now when workflow from list 1 is updating item on list 2, then item added event of list 2 triggers the workflow on it and then workflow 2 from list 2 starts to copy the item from list 2 to list 1 and this cycle continues...

How to stop this please guide .

Thanks

Answer 1

You can implement this method

public static void SystemUpdate(this SPListItem item, bool incrementListItemVersion, bool doNotFireEvents)
{
    SPItemEventReceiverHandling rh = new SPItemEventReceiverHandling();
    if (doNotFireEvents)
    {
        try
        {
            rh.DisableEventFiring();
            item.SystemUpdate(incrementListItemVersion);
        }
        finally
        {
            rh.EnableEventFiring();
        }
    }
    else
    {
        item.SystemUpdate(incrementListItemVersion);
    }
}

internal class SPItemEventReceiverHandling : SPItemEventReceiver
{
    public new void DisableEventFiring()
    {
        base.DisableEventFiring();
    }

    public new void EnableEventFiring()
    {
        base.EnableEventFiring();
    }
}

You should use this method to update item in your workflow. In this case the event does not fired. So the workflow does not started )

Answer 2

One of the ways to prevent it is to create a special boolean column and to use it as flag. You can set it from the workflow and then check it in event receiver - if it's true you need to set it to false in event receiver and return with no further action. It's no so elegant but it works. :)