XamarinDevDays/Demos/app-tasks/DevDaysTasks.Shared/Views/TodoList.xaml.cs

using System;
using Xamarin.Forms;

namespace DevDaysTasks
{
    public partial class TodoList : ContentPage
    {

        TodoListViewModel viewModel;
        public TodoList()
        {
            InitializeComponent();
            BindingContext = viewModel = new TodoListViewModel();
        }

        protected override void OnAppearing()
        {
            base.OnAppearing();

            viewModel.RefreshCommand.Execute(false);
        }

        // Event handlers
        public async void OnSelected(object sender, SelectedItemChangedEventArgs e)
        {
            var list = (ListView)sender;
            var todo = e.SelectedItem as TodoItem;
            if (Device.OS != TargetPlatform.iOS && todo != null)
            {
                // Not iOS - the swipe-to-delete is discoverable there
                if (Device.OS == TargetPlatform.Android)
                {
                    await DisplayAlert(todo.Name, "Press-and-hold to complete task " + todo.Name, "Got it!");
                }
                else
                {
                    // Windows, not all platforms support the Context Actions yet
                    if (await DisplayAlert("Mark completed?", "Do you wish to complete " + todo.Name + "?", "Complete", "Cancel"))
                    {
                        viewModel.CompleteCommand.Execute(todo);
                    }
                }
            }

            // prevents background getting highlighted
            list.SelectedItem = null;
        }

        // http://developer.xamarin.com/guides/cross-platform/xamarin-forms/working-with/listview/#context
        public void OnComplete(object sender, EventArgs e)
        {
            var mi = ((MenuItem)sender);
            var todo = mi.CommandParameter as TodoItem;
            viewModel.CompleteCommand.Execute(todo);
        }
    }
}