In this section, we will take a look at how to update our code-behind file for our WalksMainPage to create and implement a FadingEntrance animation with the FadeTo extension method in the OnAppearing method, using C# code that will be called whenever our ContentPage is displayed.

Let's start updating the code-behind for our WalksMainPage by performing the following steps:

1. Locate and open the WalksMainPage.xaml.cs code-behind file, which is located in the Views folder, ensure that it is displayed in the code editor, and enter the following highlighted code sections:

     //
     //  WalksMainPage.xaml.cs
     //  Displays Walk Information in a ListView control from an array 
     //
     //  Created by Steven F. Daniel on 14/05/2018
     //  Copyright © 2018 GENIESOFT STUDIOS. All rights reserved.
     //
     using System;
     using TrackMyWalks.Models;
     using TrackMyWalks.Services;
     using TrackMyWalks.ViewModels;
     using Xamarin.Forms;
 
     namespace TrackMyWalks.Views
     {
         public partial class WalksMainPage : ContentPage
         {
             // Return the Binding Context for the ViewModel
             WalksMainPageViewModel _viewModel => 
                                    BindingContext as WalksMainPageViewModel;
 
             public WalksMainPage()
             {
                 InitializeComponent();
                 ...
                 ...
             }
             ...
             ...
             // Method to initialise our View Model when the ContentPage appears
             protected override async void OnAppearing()
             {
                 base.OnAppearing();
 
                 if (_viewModel != null)
                 {
                     // Call the Init method to initialise the ViewModel
                     await _viewModel.Init();
                 }
 
                 // Create a FadingEntrance Animation to fade our WalkEntriesListView
                 WalkEntriesListView.Opacity = 0;
                 await WalkEntriesListView.FadeTo(1, 4000);
                 ...
                 ...
             }
         }
     }

Let's take a look at what we covered in the preceding code snippet:

1. We started by modifying our OnAppearing method to create a FadingEntrance animation, and set the Opacity property for our WalkEntriesListView to fade our ListView.
2. We used the FadeTo extension method, which will animate our WalkEntriesListView, and we specified the Opacity value to fade to, as well as specifying a duration in milliseconds of 4 seconds over which to animate the transition.