This is the .NET Standard library that all the platform-specific projects reference and the location that most of our code will be added to. The following screenshot displays the structure of the .NET Standard library:
Under Dependencies, we will find references to any external dependencies, such as Xamarin.Forms. We will update the Xamarin.Forms package version in the Updating Xamarin.Forms packages section of this chapter and add more dependencies as we progress through the chapter.
The App.xaml file is an XAML file that represents the app. This is a good place to put application-wide resources, which we will do later on. We can also see the App.xaml.cs file, which contains the start up code and some application lifetime events that we can add custom code to, such as OnStart or OnSleep.
If we open up App.xaml.cs, we can see the starting point for our Xamarin.Forms application:
public partial class App : Application
{
public App()
{
InitializeComponent();
MainPage = new DoToo.MainPage();
}
protected override void OnStart()
{
// Handle when your app starts
}
// code omitted for brevity
}
The MainPage property is assigned to a page, which is particularly important as this is what determines which page is first shown to the user. In this template, this is the DoToo.MainPage() class.
The last two files are the MainPage.xaml file, which contains the first page of the application, and the code-behind file, which is called MainPage.xaml.cs. These files are removed in order to comply with the Model–View–View–Model (MVVM) naming standards.
