Introduction
Note
.NET MAUI is the next evolution of Xamarin and what we recommend you develop mobile and desktop apps with, and you can learn more about .NET MAUI in several training modules. This Xamarin training module will not be maintained going forward.
Think about the applications that are installed on your phone. You might have some games, social media apps, storage apps, and so on. As an exercise, try to think of any applications that have absolutely no connection to the internet. You might come up with some, but the chances are that most of your apps have some form of connection to the internet. Users expect apps to have social aspects or cross-device experiences. Because of that, if an application doesn't have a social aspect, users won't use it.
In this module, you build a Xamarin.Forms application that consumes data from a REST web service. You start by determining if your device is connected to the internet and only running code if you have an active connection. Then you use HttpClient to perform basic CRUD operations on a hosted REST web service. Finally, you use message handlers with HttpClient to take advantage of the native networking stacks on each device.
Note
This module requires Visual Studio 2019. You can use either Windows or a Mac:
- Windows: Make sure you have the Mobile development with .NET workload installed in Visual Studio 2019 for Windows. Refer to the documentation if you need to add it to your installation.
- macOS: The standard Visual Studio 2019 for Mac installation includes everything you need to build mobile apps with Xamarin.
Learning objectives
In this module, you will:
- Detect if your device is connected to the internet
- Consume a REST web service by using HttpClient
- Take advantage of the native networking stacks while using HttpClient
Prerequisites
- Visual Studio 2019 (any edition)
- Familiarity with C# and .NET
- Basic knowledge of REST