Question

Is there an event handler that will be called when an item is added in a listbox in WPF?

Thanks!

Answer 1

The problem is that the INotifyCollectionChanged interface which contains the event handler is explicitly implemented, which means you have to first cast the ItemCollection before the event handler can be used:

public MyWindow()   
{   
    InitializeComponent();   

    ((INotifyCollectionChanged)mListBox.Items).CollectionChanged +=   
        mListBox_CollectionChanged;   
}   

private void mListBox_CollectionChanged(object sender,    
    NotifyCollectionChangedEventArgs e)   
{   
    if (e.Action == NotifyCollectionChangedAction.Add)   
    {   
        // scroll the new item into view   
        mListBox.ScrollIntoView(e.NewItems[0]);   
    }       
}

Ref.

Josh’s advice about the observable collection should also be considered.