Catrobat.IDE.WindowsPhone.Controls.ListsViewControls.SelectableGridView.OnSelectionChanged C# (CSharp) Method

        private void OnSelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            foreach (object item in e.RemovedItems)
            {
                if (item is ISelectable)
                    ((ISelectable)item).IsSelected = false;
                else
                {
                    if (Debugger.IsAttached)
                        throw new ArgumentException(
                            "All items have to implement the ISelectabe interface.");
                }
            }

            foreach (object item in e.AddedItems)
            {
                if (item is ISelectable)
                    ((ISelectable)item).IsSelected = true;
                else
                {
                    if (Debugger.IsAttached)
                        throw new ArgumentException(
                            "All items have to implement the ISelectabe interface.");
                }
            }
        }
    }