Book Image

Modern Web Development with ASP.NET Core 3 - Second Edition

By : Ricardo Peres
Book Image

Modern Web Development with ASP.NET Core 3 - Second Edition

By: Ricardo Peres

Overview of this book

ASP.NET has been the preferred choice of web developers for a long time. With ASP.NET Core 3, Microsoft has made internal changes to the framework along with introducing new additions that will change the way you approach web development. This second edition has been thoroughly updated to help you make the most of the latest features in the framework, right from gRPC and conventions to Blazor, which has a new chapter dedicated to it. You’ll begin with an overview of the essential topics, exploring the Model-View-Controller (MVC) pattern, various platforms, dependencies, and frameworks. Next, you’ll learn how to set up and configure the MVC environment, before delving into advanced routing options. As you advance, you’ll get to grips with controllers and actions to process requests, and later understand how to create HTML inputs for models. Moving on, you'll discover the essential aspects of syntax and processes when working with Razor. You'll also get up to speed with client-side development and explore the testing, logging, scalability, and security aspects of ASP.NET Core. Finally, you'll learn how to deploy ASP.NET Core to several environments, such as Azure, Amazon Web Services (AWS), and Docker. By the end of the book, you’ll be well versed in development in ASP.NET Core and will have a deep understanding of how to interact with the framework and work cross-platform.
Table of Contents (26 chapters)
Section 1: The Fundamentals of ASP.NET Core 3
Section 2: Improving Productivity
Section 3: Advanced Topics
Appendix A: The dotnet Tool

Model validation

We all know that client-side validation by validating a page without having to post its content is what we expect from a web app these days. However, this may not be sufficient—for example for the (granted, few) cases where JavaScript is disabled. In this case, we need to ensure we validate our data on the server-side before actually doing anything with it. ASP.NET Core supports both scenarios; let's see how.

Server-side validation

The result of validating a submitted model (normally through POST) is always available in the ModelState property of the ControllerBase class, and it is also present in the ActionContext class. Consider the following code snippet:

if (!this.ModelState.IsValid)
if (this.ModelState["Email"].Errors.Any())
var emailErrors = string.
Join(Environment.NewLine, this.ModelState
["Email"].Errors.Select(e => e.ErrorMessage));

As you can...