Solution 1:

The following usually works:

Context.Refresh(RefreshMode.StoreWins, _
    Context.ObjectStateManager.GetObjectStateEntries())

It sometimes causes problems with EntityRelations. look at my comment for further details.

Solution 2:

You can use this code:

public void RefreshAll()
{
     // Get all objects in statemanager with entityKey 
     // (context.Refresh will throw an exception otherwise) 
     var refreshableObjects = (from entry in context.ObjectStateManager.GetObjectStateEntries(
                                                 EntityState.Deleted 
                                               | EntityState.Modified 
                                               | EntityState.Unchanged)
                                      where entry.EntityKey != null
                                      select entry.Entity);

     context.Refresh(RefreshMode.StoreWins, refreshableObjects);
}

I wrote a post on how to RefreshAll() and refresh the context in some other ways:

http://christianarg.wordpress.com/2013/06/13/entityframework-refreshall-loaded-entities-from-database/