CollectionChanged event of observablecollection in c#
<p>How can write this code better:</p>

<pre><code>void CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
    if (sender is ObservableCollection&lt;PromotionPurchaseAmount&gt;)
    {
        if (e.Action == NotifyCollectionChangedAction.Remove)
        {
            foreach (PromotionPurchaseAmount item in e.NewItems)
            {
                //Removed items
                item.PropertyChanged -= EntityViewModelPropertyChanged;
            }
        }
        else if (e.Action == NotifyCollectionChangedAction.Add)
        {
            foreach (PromotionPurchaseAmount item in e.NewItems)
            {
                //Added items
                item.PropertyChanged += EntityViewModelPropertyChanged;
            }
        }
    }
    else if (sender is ObservableCollection&lt;PromotionItemPricing&gt;)
    {
        if (e.Action == NotifyCollectionChangedAction.Remove)
        {
            foreach (PromotionItemPricing item in e.NewItems)
            {
                //Removed items
                item.PropertyChanged -= EntityViewModelPropertyChanged;
            }
        }
        else if (e.Action == NotifyCollectionChangedAction.Add)
        {
            foreach (PromotionItemPricing item in e.NewItems)
            {
                //Added items
                item.PropertyChanged += EntityViewModelPropertyChanged;
            }
        }
    }
    else if (sender is ObservableCollection&lt;PromotionItem&gt;)
    {
        if (e.Action == NotifyCollectionChangedAction.Remove)
        {
            foreach (PromotionItem item in e.NewItems)
            {
                //Removed items
                item.PropertyChanged -= EntityViewModelPropertyChanged;
            }
        }
        else if (e.Action == NotifyCollectionChangedAction.Add)
        {
            foreach (PromotionItem item in e.NewItems)
            {
                //Added items
                item.PropertyChanged += EntityViewModelPropertyChanged;
            }
        }
    }
}
</code></pre>
