ReactiveLIst ItemsAdded
<p>Regarding ReactiveList, and the ItemsAdded property. I had a list of Journal items stored in a ReactiveList:</p>

<pre><code>public ReactiveList&lt;account.JournalViewModel&gt; JournalEntries { get; private set; }
</code></pre>

<p>And I have a Readonly property to display the Balance of all the Journal Items:</p>

<pre><code>readonly ObservableAsPropertyHelper&lt;decimal&gt; _balance;
public decimal Balance { get { return _balance.Value; } }
</code></pre>

<p>In the Constructor of the ViewModel, I instantiate the ReactiveList, and set the ObservableAsPropertyHelper:</p>

<pre><code>this.JournalEntries = new ReactiveList&lt;account.JournalViewModel&gt;();
this.JournalEntries.ChangeTrackingEnabled = true;
this.WhenAnyObservable(vm =&gt; vm.JournalEntries.ItemsAdded)
    .Select(_ =&gt; this.JournalEntries.Sum(j =&gt; j.CreditAmount) - this.JournalEntries.Sum(j =&gt; j.DebitAmount))
    .ToProperty(this, vm =&gt; vm.Balance, out _balance);
</code></pre>

<p>Then, still in the constructor but further down, I add items to the ReactiveList:</p>

<pre><code>foreach (var j in journalEntries)
     this.JournalEntries.Add(new account.JournalViewModel(j, this));
</code></pre>

<p>However this does not set the Balance property, and I don't know why. However if I change the property to a regular ol' Observable:</p>

<pre><code>decimal _balance;
public decimal Balance { get { return _balance; } set { this.RaiseAndSetIfChanged(ref _balance, value); } }
</code></pre>

<p>And, in the constructor, Subscribe to the ItemsAdded Observable:</p>

<pre><code>this.WhenAnyObservable(vm =&gt; vm.JournalEntries.ItemsAdded)
    .Subscribe(_ =&gt; this.Balance = this.JournalEntries.Sum(j =&gt; j.CreditAmount) - this.JournalEntries.Sum(j =&gt; j.DebitAmount));
</code></pre>

<p>When I add the Journal items, the desired result is achieved. I was hoping someone better skilled than I am could answer why the first method won't work. Is there a way to make it work that I am unaware of?</p>