Book Image

C# 8.0 and .NET Core 3.0 – Modern Cross-Platform Development - Fourth Edition

By : Mark J. Price
Book Image

C# 8.0 and .NET Core 3.0 – Modern Cross-Platform Development - Fourth Edition

By: Mark J. Price

Overview of this book

In C# 8.0 and .NET Core 3.0 – Modern Cross-Platform Development, Fourth Edition, expert teacher Mark J. Price gives you everything you need to start programming C# applications. This latest edition uses the popular Visual Studio Code editor to work across all major operating systems. It is fully updated and expanded with new chapters on Content Management Systems (CMS) and machine learning with ML.NET. The book covers all the topics you need. Part 1 teaches the fundamentals of C#, including object-oriented programming, and new C# 8.0 features such as nullable reference types, simplified switch pattern matching, and default interface methods. Part 2 covers the .NET Standard APIs, such as managing and querying data, monitoring and improving performance, working with the filesystem, async streams, serialization, and encryption. Part 3 provides examples of cross-platform applications you can build and deploy, such as web apps using ASP.NET Core or mobile apps using Xamarin.Forms. The book introduces three technologies for building Windows desktop applications including Windows Forms, Windows Presentation Foundation (WPF), and Universal Windows Platform (UWP) apps, as well as web applications, web services, and mobile apps.
Table of Contents (21 chapters)

Manipulating data with EF Core

Inserting, updating, and deleting entities using EF Core is an easy task to accomplish. DbContext maintains change tracking automatically, so the local entities can have multiple changes tracked, including adding new entities, modifying existing entities, and removing entities. When you are ready to send those changes to the underlying database, call the SaveChanges method. The number of entities successfully changed will be returned.

Inserting entities

Let's start by looking at how to add a new row to a table.

  1. In Program, create a new method named AddProduct, as shown in the following code:
    static bool AddProduct(int categoryID, string productName, decimal? price)
      using (var db = new Northwind())
        var newProduct = new Product
          CategoryID = categoryID, 
          ProductName = productName, 
          Cost = price
        // mark product as added in change tracking
        // save tracked...