I experienced a different ListChanged event behavior of BLB between v3.5.2 and v3.6.0 when a property of a containing child object changed. In version 3.5.3 the ListChanged event was called only once, as I expected. In version 3.6.0 the ListChanged event is called two times??
A Happy and Successful New Year to the Fantastic CSLA Team,
Andreas
Hi,
Unfortunately I was not able find the problem by debugging Csla 3.6 why OnListChanged is called two times after a property of a child item was changed. This behavior gets me in trouble with my current business logic and causes performance decreases as well. I would really appreciate if someone can figure out if this is a bug and may get fixed sometime (or if I have to life with it and need to change my business logic).I've written a small test program:
using System;
using
System.Collections.Generic;using
System.Linq;using
System.Text;using
Csla;namespace
OnListChanged{
public class Person : Csla.BusinessBase<Person>
{
public Person()
{
}
public static PropertyInfo<string> NameProperty =
RegisterProperty<string>(new PropertyInfo<string>("Name"));
public string FirstName
{
get
{
return GetProperty<string>(NameProperty);
}
set
{
SetProperty<string>(NameProperty, value);
}
}
}
public class PersonList : Csla.BusinessListBase<PersonList, Person>
{
public PersonList() { }
protected override void OnListChanged(System.ComponentModel.ListChangedEventArgs e)
{
base.OnListChanged(e);
}
protected override void OnChildChanged(Csla.Core.ChildChangedEventArgs e)
{
base.OnChildChanged(e);
}
}
class Program
{
static void Main(string[] args)
{
PersonList list = new PersonList();
// this caueses PersonList.OnListChanged to be called one time, as expected
list.Add(new Person());
Person bo = list[0];
// this caueses PersonList.OnChildChanged to be called one time (as expected)
// and PersonList.OnListChanged to be called two times...?
bo.FirstName = "Peter";
}
}
}
Sometimes I get talked into adding features to the framework because they are really good features. And then later I really regret the decision.
The ChildChanged event is a good example, and is the root cause of this issue.
Sometimes when a child object changes, it needs to raise a ListChanged from the parent. Other times it doesn't. Yet always it needs to raise the ChildChanged events all the way to the root. This turns out to be really quite complex.
I thought I had it right, but I am seeing the same issue you are, and it is most certainly because of ChildChanged :(
So, back to the drawing board...
I believe I've fixed this issue (also noted in other threads), but would appreciate confirmation. You should be able to replace your BLB with the latest code in svn:
http://www.lhotka.net/cslacvs/viewvc.cgi/trunk/cslacs/Csla/BusinessListBase.cs?view=log
And I think it will now work. My unit tests showing double-events and inconsistent behavior before/after serialization are now passing at least.
RockfordLhotka:
I believe I've fixed this issue (also noted in other threads), but would appreciate confirmation.
Excellent, thank you!!
Rocky
From: tetranz
[mailto:cslanet@lhotka.net]
Sent: Thursday, January 22, 2009 8:26 AM
To: rocky@lhotka.net
Subject: Re: [CSLA .NET] Different ListChanged event behavior in 3.5.2
vs 3.6.0
Thanks Rocky. It's working well
for me now.
RockfordLhotka:
I believe I've fixed this issue (also noted in other
threads), but would appreciate confirmation.
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