New ObservableCollection and adding elements to the loop

Question

In terms of speed and number of generated notifications , this code:

ObservableCollection<Foo> foo = new ObservableCollection<Foo>(bar); this.SomeProperty = foo; 

same as:

 this.SomeProperty = new ObservableCollection<Foo>(); foreach (var v in bar) { this.SomeProperty.Add(v); } 

If they are the same, is it possible to somehow disable the generated notifications?

Goal: I'm trying to speed up the show of Telerik RadChart in silverlight. It seems to take some time to display (and freeze in the browser application) even after setting a property containing an ObservableCollection. Once the chart is drawn, everything works correctly.

Answer 1

• Profile it or check! According to the docs, the PropertyChanged event occurs when an item is added, deleted, changed, moved or updated the entire list. Therefore, you can write some test code that only subscribes to this event and sees what happens.

• A fast and reliable observable collection - if this is due to a constant barrage of OnChanged events, just think about getting fired after a massive update - someone has already done this job for you

• http://www.telerik.com/help/silverlight/radchart-performance-tips-and-tricks.html deals specifically with the script that you describe about halfway down the page. Their output is similar to 2 - in fact, the code looks very similar :-)

If freezing occurs before the actual binding is done, I would make sure that the delay is not really based on or due to other activity (for example, the time it takes to load the collection). Again, profiling is your friend.