public TodoListPageModel(ITodoItemService todoItemService)
{
_todoItemService = todoItemService;
Todos = new ObservableCollection <TodoItemViewModel>();
// Todo: Unsubscribe events in case the view models view would be removed from the navigation stack
MessagingCenter.Instance.Subscribe <ITodoItemService, TodoItem>(
this,
Messages.TodoItemsAdded,
(sender, todo) =>
{
Todos.Add(new TodoItemViewModel(_todoItemService, todo));
});
MessagingCenter.Instance.Subscribe <ITodoItemService, TodoItem>(
this,
Messages.TodoItemsRemoved,
(sender, todo) =>
{
var vm = Todos.SingleOrDefault(t => t.TodoItem.Id == todo.Id);
if (vm != null)
{
Todos.Remove(vm);
}
});
AddTodoCommand = new Command(
() =>
{
CoreMethods.PushPageModel <AddTodoItemPageModel>();
});
DeleteTodoCommand = new Command <TodoItemViewModel>(
async(todo) =>
{
if (await CoreMethods.DisplayAlert(
"Delete todo",
$"Do you really want to delete todo '{todo.Name}'?",
"Yes", "No") == false)
{
return;
}
await _todoItemService.RemoveTodoAsync(todo.TodoItem);
SelectedTodo = null;
DeleteTodoCommand.ChangeCanExecute();
},
(todo) => SelectedTodo != null);
}
