Blazor WebAssembly by Example
Description
- Build projects such as a weather app, expense tracker, and Kanban board with real-world applications
- Understand and work with Blazor WebAssembly effectively without spending too much time focusing on the theory
Book DescriptionBlazor 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#.What you will learn - Discover the power of the C# language for both server-side and client-side web development
- Use the Blazor WebAssembly App project template to build your first Blazor WebAssembly application
- Use templated components and the Razor class library to build and share a modal dialog box
- Understand how to use JavaScript with Blazor WebAssembly
- Build a progressive web app (PWA) to enable native app-like performance and speed
- Understand dependency injection (DI) in.NET to build a shopping cart app
- Get to grips with.NET Web APIs by building a task manager app
Who this book is forThis book is for.NET web developers who are tired of constantly learning new JavaScript frameworks and wish to write web applications using Blazor WebAssembly, leveraging the power of.NET and C#. The book assumes beginner-level knowledge of the C# language,.NET framework, Microsoft Visual Studio, and web development concepts.
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Persons
Toi B. Wright has been obsessed with ASP.NET for almost 20 years. She is the founder and president of the Dallas ASP.NET User Group. She has been a Microsoft MVP in ASP. NET for 18 years and is also an ASPInsider. She is an experienced full-stack software developer, book author, courseware author, speaker, and community leader with over 25 years of experience. She has a B.S. in computer science and engineering from the Massachusetts Institute of Technology (MIT) and an MBA from Carnegie Mellon University (CMU).
Content
- Building Your First Blazor WebAssembly Application
- Building a Modal Dialog Using Templated Components
- Building a Local Storage Service Using JavaScript Interoperability (JS Interop)
- Building a Weather App as a Progressive Web App (PWA)
- Building a Shopping Cart Using Application State
- Building a Kanban Board Using Events
- Building a Task Manager Using ASP.NET Web API
- Building an Expense Tracker Using the EditForm Component
Chapter 1: Introduction to Blazor WebAssembly
Blazor WebAssembly is Microsoft's new single-page application (SPA) framework for building web applications on .NET Framework. It enables developers to run C# code on the client. Therefore, instead of being forced to use JavaScript on the browser, we can now use C# on the browser.
In this chapter, we will prepare you to develop web applications using Blazor WebAssembly. We will discuss the two different Blazor hosting models and present the advantages of using Blazor WebAssembly over Blazor Server. Finally, we will guide you through the process of setting up your computer to complete the projects in this book.
In this chapter, we will cover the following topics:
- Benefits of using the Blazor framework
- Differences between the two hosting models
- What is WebAssembly?
- Setting up your PC
Benefits of using the Blazor framework
Using the Blazor framework has several benefits. For starters, it is a free and open source framework built on Microsoft's robust .NET Framework. Also, it is an SPA framework that uses Razor syntax and can be developed using Microsoft's exceptional tooling.
.NET Framework
Blazor is built on .NET Framework. Since Blazor is built on .NET Framework, anyone familiar with .NET Framework can quickly become productive using the Blazor framework. The Blazor framework leverages the robust ecosystem of .NET libraries and NuGet packages from .NET Framework. Also, since both client and server code are written in C#, they can share code and libraries, such as the application logic used for data validation.
Blazor is open source. Since Blazor is a feature of the ASP.NET framework, all of the source code for Blazor is available on GitHub as part of the dotnet/aspnetcore repository that is owned by the .NET Foundation. .NET Foundation is an independent, non-profit organization established to support the innovative, commercially friendly, open source ecosystem around the .NET platform. The .NET platform has a strong community of over 100,000 contributions from more than 3,700 companies.
Blazor is free. Since .NET Framework is free, this means that Blazor is also free. There are no fees or licensing costs associated with using Blazor, including for commercial uses.
SPA framework
The Blazor framework is an SPA framework. As the name implies, an SPA is a web app that consists of a single page. The application dynamically rewrites the single page instead of loading an entirely new page in response to each UI update. The goal is faster transitions that make the web app feel more like a native app.
When a page is rendered, Blazor creates a render tree that is a graph of the components on the page. It is similar to the Document Object Model (DOM) created by the browser. However, it is a virtual DOM. Updates to the UI are applied to the virtual DOM and only the differences between the DOM and the virtual DOM are updated by the browser.
Razor syntax
The name of the Blazor framework has an interesting origin story. The term Blazor is a combination of the word browser and the word razor. Razor is the ASP.NET view engine used to create dynamic web pages with C#. Razor is a syntax for combining HTML markup with C# code that was designed for developer productivity. It allows the developer to use both HTML markup and C# in the same file.
Blazor web apps are built using Razor Components. Razor Components are reusable UI elements that contain C# code, markup, and other Razor Components. Razor Components are quite literally the building blocks of the Blazor framework. For more information on Razor Components, refer to Chapter 2, Building Your First Blazor WebAssembly Application.
Important note
Razor Pages and MVC also use the Razor syntax. Unlike Razor Pages and MVC, which render the whole page, Razor Components only render the DOM changes. One way to easily distinguish between them is that Razor components use the RAZOR file extension, while Razor Pages use the CSHTML file extension.
Awesome tooling
You can use either Microsoft Visual Studio or Microsoft Visual Studio Code to develop Blazor WebAssembly applications. Microsoft Visual Studio is an integrated development environment (IDE), while Microsoft Visual Code is a lightweight, yet powerful, editor. They are both incredible tools for building enterprise applications. Also, they are both available for free and there are versions that run on Windows, Linux, and macOS.
There are many benefits associated with using the Blazor framework to develop web apps. Since it is built on the mature .NET Framework, it enables developers to use the skills, such as C#, and the tools, such as Visual Studio, that they have already mastered. Also, since it is an SPA framework, Blazor web apps feel like native apps.
Hosting models
Blazor has two different hosting models. The first hosting model that Microsoft released is the Blazor Server model. In this hosting model, the web app is executed on the server. The second hosting model that Microsoft released, and the topic of this book, is the Blazor WebAssembly model. In this hosting model, the web app is executed on the browser.
Each hosting model has its own advantages and disadvantages. However, they both use the same underlying architecture. Therefore, it is possible to write and test your code independent of the hosting model. The major differences between the two hosting models concern latency, security, data access, and offline support.
Blazor Server
As we just mentioned, the Blazor Server hosting model was the first hosting model released by Microsoft. It was released as part of the .NET Core 3 release in September 2019.
The following diagram illustrates the Blazor Server hosting model:
Figure 1.1 - Blazor Server
In this hosting model, the web app is executed on the server and only updates to the UI are sent to the client's browser. The browser is treated as a thin client and all of the processing occurs on the server. When using Blazor Server, UI updates, event handling, and JavaScript calls are all handled over an ASP.NET Core SignalR connection.
Important note
SignalR is a software library that allows the web server to push real-time notifications to the browser. Blazor Server uses it to send UI updates to the browser.
Advantages of Blazor Server
There are a few advantages of using Blazor Server versus using Blazor WebAssembly. However, the key advantage is that everything happens on the server. Since the web app runs on the server, it has access to everything on the server. As a result, security and data access are simplified. Also, since everything happens on the server, the assemblies (DLLs) that contain the web app's code remain on the server.
Another advantage of using Blazer Server is that it can run on thin clients and older browsers, such as Internet Explorer, that do not support WebAssembly.
Finally, the initial load time for the first use of a web app that is using Blazor Server can be much less than that of a web app that is using Blazor WebAssembly because there are fewer files to download.
Disadvantages of Blazor Server
The Blazor Server hosting model has a number of disadvantages versus Blazor WebAssembly due to the fact that the browser must maintain a constant connection to the server. Since there is no offline support, every single user interaction requires a network roundtrip. As a result of all of these roundtrips, Blazor Server web apps have higher latency than Blazor WebAssembly web apps and can feel sluggish.
Tip
Latency is the time between the UI action and the time when the UI is updated.
Another disadvantage of using Blazor Sever is that it relies on SignalR for every single UI update. Microsoft's support for SignalR has been improving, but it can be challenging to scale.
Finally, a Blazor Server web app must be served from an ASP.NET Core server.
Blazor WebAssembly
The Blazor WebAssembly hosting model is the most recent hosting model released by Microsoft, and the topic of this book. Blazor WebAssembly 3.2.0 was released in May 2020. Blazor WebAssembly in .NET 5 was released as part of the .NET 5.0 release in November 2020 and it is not a long-term support (LTS) release. This book will be using Blazor WebAssembly in .NET 5 for all of the projects.
Tip
LTS releases are supported by Microsoft for at least 3 years after their initial release. Blazor WebAssembly in .NET 5 is not an LTS release. If you are starting a new project with Blazor WebAssembly, you...
