Book Image

Blazor WebAssembly by Example

By : Toi B. Wright
Book Image

Blazor WebAssembly by Example

By: Toi B. Wright

Overview of this book

Blazor WebAssembly makes it possible to run C# code on the browser instead of having to use JavaScript, and does not rely on plugins or add-ons. The only technical requirement for using Blazor WebAssembly is a browser that supports WebAssembly, which, as of today, all modern browsers do. Blazor WebAssembly by Example is a project-based guide for learning how to build single-page web applications using the Blazor WebAssembly framework. This book emphasizes the practical over the theoretical by providing detailed step-by-step instructions for each project. You'll start by building simple standalone web applications and progress to developing more advanced hosted web applications with SQL Server backends. Each project covers a different aspect of the Blazor WebAssembly ecosystem, such as Razor components, JavaScript interop, event handling, application state, and dependency injection. The book is designed in such a way that you can complete the projects in any order. By the end of this book, you will have experience building a wide variety of single-page web applications with .NET, Blazor WebAssembly, and C#.
Table of Contents (11 chapters)

Using the Geolocation API

The Geolocation API for JavaScript provides a mechanism for us to obtain the location of a user. Using the Geolocation API, we can obtain the coordinates of a device that the browser is running on.

The Geolocation API is accessed through a navigator.geolocation object. When we make a call to the navigator.geolocation object, the user's browser asks the user for permission to access their location. If they accept, the browser uses the device's positioning hardware, such as the Global Positioning System (GPS) on a smart phone, to determine its location.

Before we attempt to use the navigator.geolocation object, we should verify that it is supported by the browser. The following code tests for the presence of geolocation support on the browser:

if (navigator.geolocation) {
    var position = await getPositionAsync();  
} else {
    throw Error("Geolocation is not supported.");
}...