Beginning C# 7 Hands-On – Advanced Language Features: Learn the advanced-level features of C# 7 using Visual Studio 2017

Beginning C# 7 Hands-On – Advanced Language Features

Learn the advanced-level features of C# 7 using

Visual Studio 2017

Tom Owsiak

BIRMINGHAM - MUMBAI

Beginning C# 7 Hands-On – Advanced Language Features

Copyright © 2017 Packt Publishing

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First published: October 2017

Production reference: 1271017

Published by Packt Publishing Ltd.

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B3 2PB, UK.

ISBN 978-1-78829-426-3

www.packtpub.com

Credits

About the Author

Tom Owsiak has eight years of experience as a teacher in Mathematics, Physics, Statistics, and Programming. He has worked for five years as a database programmer using various technologies such as .NET, Clipper, SQL, SQL Server, SAS, and Excel, and many related technologies.

Tom is the publisher of one of the most successful courses on Udemy, called Learn C# With Visual Studio 2013. Currently, Tom works as a Mathematics and Computer Science teacher at Mercy College in Dobbs Ferry, NY.

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Table of Contents

Preface

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Downloading the color images of this book

Errata

Piracy

Questions

Creating a Simple Generics Class

Creating a generics class

Working with different data types

Making parameters that are generic

Displaying the values

Adding a button to Default.aspx

Initializing a collection of integers to their array and displaying the results

Changing the data types in our generics class

Running the program

Accumulating the input

Chapter review

Summary

Creating a Generic Method

Creating a button to exchange and then comparing two values

Writing a swap function

Comparing values using the CompareTo method

Introducing constraints

Completing the GenMethods class

Hardcoding the values

Running the program

Modifying the program for an additional type of comparison

Modifying the program for different data types

Chapter review

Summary

Implementing a Generic Interface to Accomplish Sorting

Adding a button to sort and display results

Creating a generics interface class

Implementing the interface

Adding a virtual function

Adding refinements

Entering the reference code

Upcasting

Downcasting

Running the program

Chapter review

Summary

Making Delegates More Flexible with Generics

Adding a summarize button to the HTML

Constructing a delegate

Assigning functions to represent the delegate

Calling the delegate

Running the program

Summary

Creating and Using Generic Dictionaries

Adding a show button to the HTML

Starting a process from a web page

Making a verbatim string

Iterating over key-value pairs

Making a directory and creating a file from Command Prompt

Chapter review

Summary

Connection Between Delegates and Lambda Expressions

Adding a Show Results button to the HTML

Adding delegates

Setting up the variables

Making objects of the delegate type

Defining lambda expressions

Operating an array

Working with actions

Chapter review

Summary

Expression-Bodied Lambdas and Expression-Bodied Members

Adding a box and a Find Max button to the HTML

Making the delegate

Defining an expression-bodied member

Converting an array of strings into an array of doubles

Creating an expression-bodied lambda

Comparing values

Specifying the parameters

Running the program

Chapter review

Summary

Anonymous Methods and Objects That Run Their Own Delegates

Adding a Show Results button to the HTML

Streamlining writing functions

Performing an action on all of the values

Making an anonymous function or method

Starting a thread

Running and modifying the program

Chapter review

Summary

C# with LINQ and Built-In Types

Adding a Show Values button to the HTML

Adding namespaces

Working with the IEnumerable generic interface

Converting an array to a list of integers

Determining the values in a collection

Converting the values back to a list

Extracting values from the list and sorting them

Running the program

Chapter review

Summary

C# with LINQ and Custom Data Types

Adding a Show People button to the HTML

Setting up a database

Making a custom type using LINQ

Setting up an array of people

Querying the array

Running the program

Chapter review

Summary

Using Query Syntax to Construct Queries

Adding a show button to the HTML

Creating a decimal salary array

Working with range variables

Selecting a salary range and putting it in descending order

Displaying the results

Observing deferred execution

Making a dictionary

Working with key-value pairs

Querying the data in the key-value pairs

Running the program

Chapter review

Summary

Queries That Perform Aggregation Functions

Adding a show button to the HTML

Creating an array

Averaging the values in a list

Displaying the results

Using the Count function

Working with a list of lists

Adding students to the classList

Summarizing the information in the classList

Running the program

Chapter review

Summary

Using LINQ to Summarize Tuples

Adding a show tuple summary values button to the HTML

Introducing tuples

Adding namespaces

Making a list with a tuple

Returning the tuples

Making a list of doubles

Summarizing the list

Displaying the results

Running the program

Chapter review

Summary

Summarizing Results with Grouping

Adding a Show Results button to the HTML

Adding namespaces

Creating the student class and defining fields

Making a list of students

Grouping names

Displaying the grouped results

Chapter review

Summary

Joining Datasets with Inner Joins

Adding a Join Classes button to the HTML

Adding the namespaces

Creating the person and car classes

Making person objects

Making car objects

Making a list of owners and their cars

Joining the owners and car lists

Getting and displaying the results

Running the program

Chapter review

Summary

Downloading, Installing, and Running SQL Server 2017

Downloading SQL Server 2017 express

Selecting the installation type

Installing the package

Working with SQL server inside Visual Studio

Creating a SQL server database

Adding and defining a table

Adding fields to the table

Updating the structure of the database

Chapter review

Summary

Writing Code to Manually Connect to a Table and Retrieve Records

Adding a show records button to the HTML

Adding a namespace

Making the connection string

Connecting to SQL Server

Catching exceptions

Displaying errors

Opening the connection

Working with the SQL Server data reader

Running the program

Chapter review

Summary

Inserting Records into Tables Using Stored Procedures

Adding text boxes and a button to the HTML

Reviewing what you created already in SQL Server

Creating a new stored procedure

Updating the database structure

Adding a namespace

Building the connection string

Initializing the connection

Catching exceptions

Trying out commands

Adding the parameters

Saving the information for later retrieval

Recognizing the role of indexers

Running the program

Chapter review

Summary

Using the Nullable Feature to Make Apps More Stable

Adding a Show People button to the HTML

Adding a field to the people database

Modifying the dbo.People table

Writing the code for this project

Creating the person class

Making the properties

Making the list of people

Building the connection string

Entering the SQL-related code

Adding people to the list from the table

Displaying the records

Running the program

Chapter review

Summary

Connecting a Chart Control to SQL Server

Placing a chart into the HTML page

Adding a button to the HTML page

Adding a new table to the People database

Enabling auto-incrementation

Adding values to the new table

Coding the project

Adding a namespace

Building the connection string

Writing a SQL query

Making the command object

Opening the connection and making a SQL data reader

Running the program

Modifying the program to display the Y values

Chapter review

Summary

Using LINQ to Operate on Tables from SQL Server

Changing the data in the ExperimentValues table

Summarizing the fields

Adding the namespaces

Building the connection string

Making the SQL connection

Making an adapter

Making a data table

Populating the table with data

Displaying the summed values

Running the program

Adding comments

Chapter review

Summary

Creating a Page That Saves Text to Disk

Creating an application to save text

Creating the user interface for your project

Starting to code the project

Catching an exception

Creating a StreamWriter class

Creating a StreamReader class

Running the program

Chapter review

Summary

Creating a Page That Uses the File Upload Control

Starting our project from scratch

Adding a namespace

Saving a file to a specific location

Saving the file

Displaying messages to the user

Determining which files are stored in a directory

Determining the return type

Exploring the exceptions for EnumerateFiles

Catching the exceptions

Running the program

Chapter review

Summary

Serializing and Deserializing Objects

Adding two buttons to the HTML

Beginning to code the project

Adding namespaces

Creating a serializable class

Adding features to the serializable class

Defining the path for saving a file

Making a Person object

Handling unmanaged resources

Making a binary formatter

Serializing an object

Testing the program

Rebuilding an object from a hard drive

Displaying the results

Running the program

Chapter review

Summary

Having a Little Fun with Images with Pixel Manipulations

Manipulating an image

Adding a button and an image control to the HTML

Adding a namespace

Making a bitmap

Saving an image as a bitmap picture

Accessing a pixel's location

Manipulating the pixels

Converting the picture to a byte array

Sending out the image URL

Running the program

Chapter review

Summary

Saving an Image to SQL Server

Adding buttons and a list box to HTML

Creating a database table to store the files

Storing image files on your hard drive

Adding namespaces

Coding the application

Testing the scanning the folder function

Building the connection string

Using of the connection string

Running the program

Chapter review

Summary

Creating and Using an XML File

Adding a button to HTML

Coding the XML

Adding a namespace

Loading the XML file into your program

Iterating over the contents of the XML file

Displaying the results

Running the program

Chapter review

Summary

Creating XML Files with C#

Adding a button to HTML

Adding namespaces

Coding the XmlWriter settings

Writing to the hard drive

Formatting the results

Running the program

Chapter review

Summary

Querying XML Documents with LINQ

Adding a text box and a button to HTML

Adding namespaces

Clearing the output

Building an element tree

Saving the store XML file

Testing the program

Searching for items that meet a specific criteria

Selecting among the items that meet the search criteria

Displaying the results

Running the program

Chapter review

Summary

Preface

Beginning C# 7 Hands-On – Advanced Language Features assumes that you’ve mastered the basic elements of the C# language and that you're now ready to learn the more advanced C# language and syntax, line by line, in a working Visual Studio environment. You'll learn how to code advanced C# language topics including generics, lambda expressions, and anonymous methods. You'll learn to use query syntax to construct queries and deploy queries that perform aggregation functions. You'll work with C# 7 and SQL Server 2017 to perform complex joins and stored procedures. Explore advanced file access methods, and see how to serialize and deserialize objects—all by writing working lines of code that you can run within Visual Studio. You'll also take a look at C# through web programming with web forms. By the time you’ve finished this book, you’ll know all the critical advanced elements of the C# language and how to program everything from C# generics to XML, LINQ, and your first full MVC web applications. These are the advanced building blocks that you can then combine to exploit the full power of the C# programming language, line by line. This book is designed for beginner C# developers who have mastered the basics now, and for anyone who needs a fast reference to using advanced C# language features in practical coding examples.

What you need for this book

Visual Studio 2017, which will install and run on Windows 7 or above, and 2 GB or 4 GB of RAM is recommended. A minimum 20-50 GB of hard disk space is essential for typical installations.

Who this book is for

This book will appeal to anyone who is interested in learning how to program in C#. Previous programming experience will help you get through the initial sections with ease, although it's not mandatory to possess any experience at all.

Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning. Code words in text, database table names, folder names, filenames, file extensions, path names, dummy URLs, user input, and Twitter handles are shown as follows: Specifically, Default.aspx is a file that contains the markup of the elements on the web page.

A block of code is set as follows:

DropDownList1 runat=server AutoPostBack=True>

    Monday

    Tuesday

    Wednesday

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

DropDownList1 runat=server AutoPostBack=True>

    Monday

    Tuesday

    Wednesday

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: If you wish, click on Browse and save the file to a location you choose and click on OK.

Warnings or important notes appear like this.

Tips and tricks appear like this.

Reader feedback

Feedback from our readers is always welcome. Let us know what you think about this book—what you liked or disliked. Reader feedback is important for us as it helps us develop titles that you will really get the most out of. To send us general feedback, simply email [email protected], and mention the book's title in the subject of your message. If there is a topic that you have expertise in and you are interested in either writing or contributing to a book, see our author guide at www.packtpub.com/authors.

Customer support

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Downloading the example code

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