Updating SPListItem without triggering event receivers

I had an event receiver applied on documents wich can start, programatically of course, a workflow. In this workflow, i used to update some metadatas in my document item. However that triggers the event receiver a new time and you can imagine the infinate loop. Well! afeter googling i found that it is possible to diable the event firing just before the item.Update or the item.SystemUpdate.

In first time i used this method but i didn't made my code in a try catch bloc. After doing that my workflow runs normally and it didn't fires the events in the event receiver. Here is the code :

public static class SPListItemExtensions
{
/// 

/// Provides ability to update list item without firing event receiver.
/// 
/// 
/// Disables firing 

/// event receiver while updating item.
public static void Update(this SPListItem item, bool doNotFireEvents)
{
    SPItemEventReceiverHandling rh = new SPItemEventReceiverHandling();
    if (doNotFireEvents)
    {
        try
        {
            rh.DisableEventFiring();
            item.Update();
        }
        finally
        {
            rh.EnableEventFiring();
        }
    }
    else
    {
        item.Update();
    }
}
/// 

/// Provides ability to update list item without firing event receiver.
/// 
/// 
/// 
/// Disables firing event receiver while updating 

///item.
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);
    }
}
/// 

/// Provides ability to update list item without firing event receiver.
/// 
/// 
/// Disables firing event receiver while updating item.
public static void SystemUpdate(this SPListItem item, bool doNotFireEvents)
{
    SPItemEventReceiverHandling rh = new SPItemEventReceiverHandling();
    if (doNotFireEvents)
    {
        try
        {
            rh.DisableEventFiring();
            item.SystemUpdate();
        }
        finally
        {
            rh.EnableEventFiring();
        }
    }
    else
    {
        item.SystemUpdate();
    }
}
private class SPItemEventReceiverHandling : SPItemEventReceiver
{
    public SPItemEventReceiverHandling() { }

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

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


   }
}