Microsoft.Phone.Controls.ListPicker.OnItemsChanged C# (CSharp) Method

        protected override void OnItemsChanged(NotifyCollectionChangedEventArgs e)
        {
            base.OnItemsChanged(e);

            if ((0 < Items.Count) && (null == SelectedItem))
            {
                // Nothing selected (and no pending Binding); select the first item
                if ((null == GetBindingExpression(SelectedIndexProperty)) &&
                    (null == GetBindingExpression(SelectedItemProperty)))
                {
                    SelectedIndex = -1;
                }
            }
            else if (0 == Items.Count)
            {
                // No items; select nothing
                SelectedIndex = -1;
                ListPickerMode = ListPickerMode.Normal;
            }
            else if (Items.Count <= SelectedIndex)
            {
                // Selected item no longer present; select the last item
                SelectedIndex = Items.Count - 1;
            }
            else
            {
                // Re-synchronize SelectedIndex with SelectedItem if necessary
                if (SelectedIndex != -1 && !object.Equals(Items[SelectedIndex], SelectedItem))
                {
                    int selectedItemIndex = Items.IndexOf(SelectedItem);
                    if (-1 == selectedItemIndex)
                    {
                        SelectedItem = Items[0];
                    }
                    else
                    {
                        SelectedIndex = selectedItemIndex;
                    }
                }
            }

            // Translate it into view once layout has been updated for the added/removed item(s)
            Dispatcher.BeginInvoke(() => SizeForAppropriateView(false));
        }