Question

I couldn’t find a proper event which fires when my ComboBox.Items count changed. Is there any way to do so?

Answer 1

Bind ComboBox ItemsSource to ObservableCollection, then you can catch the event CollectionChanged of ObservableCollection

EDIT:

In wpf it is recommended to use binding instead of accessing UI element properties directly, of course better to use MVVM, but you can live without it too

in your Windows or UserControls C# code you can keep property like this

public ObservableCollection<string> MyCollection{get;set;}

Initialize it in constructor

MyCollection = new ObservableCollection<string>()
MyCollection.CollectionChanged += SomeMethod;

than name your UserControl in xaml like this

<UserControl Name="myUserControl".../>

write your ComboBox like this

<ComboBox ItemsSource="{Binding ElementName=myUserControl, Path=MyCollection}"...

now instead of adding and removing items to combobox element, add tham to MyCollection, they will appear in combobox

Hope this helps