PropertyChanged for child objects

normalham3 posted on Thursday, September 03, 2009

Is there an event that is raised at the Business root level when a child object is changed?

I'm working within Silverlight in a MVVM situation. I have a command on the Save button. I'd like to call the following when any child objects change. Before I implement this myself, I want to see if there is anything in the framework for this.

SaveCommand.RaiseCanExecuteChanged();

Many thanks,
Todd

webhead replied on Thursday, September 03, 2009

Business root can be notified when a child list or a property of a child has been changed, you can do this by overriding the OnChildChanged() event.

rfcdejong replied on Saturday, September 12, 2009

I have the same problem, but the childchange isn't being hit when the child is a list and an item within the list is changed. This count for IsDirty but also for IsValid and IsSaveable.

It would be nice if the ChildChanged event would had been triggered whenever an item within the child changed, bubbling up. Even if there are childs in childs etc.

rsbaker0 replied on Sunday, September 13, 2009

^^^^

I'm finding that my OnChildChanged() virtual override in my root is being called at least somewhat reliably when the property of an item in child BusinessListBase object is chagned. However, I have a comment in my code that the variant in which a ListChangedEventArgs is passed is the one that seems to work all the time. This doesn't necessarily give up bubbling all the way to the root from a deep descendant, though.

It's been a while since I worked on this, but I also vaguely remember an issue in which the wiring of the events was different after the object was saved once (or if you used a remote data portal), because OnDeserialized() would wire some events that didn't seem to otherwise be hooked.

 

RockfordLhotka replied on Sunday, September 13, 2009

What version of CSLA are we talking about?

Also, please remember that ChildChanged only works automatically when you are using managed backing fields for all child properties. Otherwise you need to manually hook/rehook the events as objects are created or deserialized.

rsbaker0 replied on Sunday, September 13, 2009

^^^

In my case, it's still CSLA 3.5. However, I'm still getting OnChildChanged via the ListChanged event even for unmanaged properties. This appears to be working because I call OnPropertyChanged in my setters...

 

 

RockfordLhotka replied on Sunday, September 13, 2009