protected override void InitializeDialogItems(AlertDialog.Builder builder, string[] items)
 {
     if (!keepTempSelectedItems)
         tempSelectedItems = CopyGenericList(SelectedItems);
     var checkedItems = ItemsSource.Cast<object>().Select(item => tempSelectedItems.Contains(item)).ToArray();
     builder.SetMultiChoiceItems(items, checkedItems, Dialog_Click);
 }