Learn C# Programming (In Ten Easy Steps)

This is where I explain the essential features of the C# language: data types, variables, constants, functions, keywords, namespaces, type conversion and other important components of the language

Every piece the data in your programs has data type. That’s what this lesson is all about.

Here we look at how to assign data items to named variables.

While variables – whose values can be changed - are essential in programming, sometimes you may want to make sure that a value cannot be changed.

How to document your code.

C# defines a number of special words, keywords, that mean specific things to the language. 

A function is a named block of code that can be run by calling its name.

How to use code stored in other files.

How to use some of the built-in routines to convert between data types.

As well as using methods to convert between different types, you can ‘cast’ one type to another – with some restrictions.

C# also allows you to declare and initialize local variables without specifying a type

Let’s now summarise some of the essential elements and syntax of C#. 

How to program a simple calculator.

How to run code only if some test condition is true.

How to run different bits of code when you test if something is or is not true.

How to run just one line of code after a test. And do curly brackets matter?

How to make a second test if the first one fails.

If you need to perform a number of tests, it is often quicker to write them as ‘switch statements’.

Operators are special symbols that are used to do specific operations such as add¬ition, multiplication and concatenation.

The operators you need to do calculations in C#.

How to compare two values.

How to test If X is true AND Y is true. Or if either X OR Y is true.

Operators that do arithmetic and assignment in one go.

The ++ and – operators.

What is the difference between ++a and a++?

How to handle the order in which tests are evaluated.

Multiple test conditions: good, bad or incomprehensible?

Let’s summarise what we’ve learnt about operators.

In this step I’m going to explain all about functions or methods and arguments

Here we look at functions: named blocks of code. 

Is a method the same as a function?

How to send data items to a function.

How to return data from a function.

The different types of argument that you can use in C#. 

And one more argument type.

Multiple functions with the same name. How does that work?

Functions inside functions…

A sample program showing some of the concepts we’ve discussed

Download this PDF guide to learn more about the details of the TreeView sample project described in the previous lesson.

Functions that call themselves.

Let’s quickly revise what you’ve learnt in this step of the course.

This is where things start to get really interesting. Object Orientation.

What are classes and objects?

Create a blueprint for an object.

Create an object based on the class defined in the last lesson

How to be sure an object has been created

The Visual Studio refactoring tool

This is a hands-on guide to writing code to create a simple ‘family tree’ of related classes.

Visual Studio can automate the separation of classes into code files

Methods that create an object from a class

Keywords that change scope and visibility

Special types of method that access fields of an object

Does it matter what your call the things in your programs?

Let’s quickly go over what we’ve learnt in this section.

In this step we look at arrays, indexing and iteration. 

Arrays – sequential collections of elements

How to count over list items in a loop

You can create arrays of any type of object, strings, integers, doubles or even user-defined objects

Another common way of iterating over items in an array in C# is to use a foreach loop.

Strings can be treated as arrays of characters

Using ‘while’ loops to program a word counting utility

An alternative type of ‘while’ loop

A simple text editor that you can use as a basis for adding features such as our word counter tool

Strings in C# can be manipulated using built-in methods

There is another string-like class called StringBuilder that you need to be aware of

How to embed values into a format string

C# also lets you evaluate expressions right inside a string

A quick overview of what we learnt about arrays and strings in this section

In step 7 we find out how to save and load files to and from a disk.

How to test if a file exists, copy a file and display file information using static methods.

How to use methods to find information and do operations on your disk files and directories

Streams provide numerous special routines for saving and loading data

How to save and load text data

So what use is file handling in your own projects?

Some types of project that you might want to try to program on your own

What you’ve learnt in this step

Here you can download the source code of a complex C# Launchpad application that lets you start up programs, documents and files by clicking buttons on a form. This program illustrates numerous programming techniques. You will learn:

• How to drag files and directories out of the Windows Explorer

• How to create buttons and controls at runtime

• Huw to extract and display icons for documents and programs

• How to attach event-handers in code to respond to events such as clicks

• How to create a Recently-Opened File menu

• How to attach event-handlers to menu items at runtime

• How to save and restore application properties between sessions

• How to create XML-format configuration files

….and much more

This is a great project for intermediate-level programmers. Not only will it teach you a broad range of coding techniques but it also provides you with a genuinely useful application which you may continue to develop by adding your own code.

In this step we are coming back to take a closer look at classes and methods. 

One class in several files – that’s a partial class

Some more variations on methods

Classes can be static too!

How to use static and overloaded methods

Structures and enumerated constants

What we learnt in step 8…

What to do when programs go wrong

To trap errors at runtime, you need to handle exceptions

You can catch more than one exception type in a try..catch block. Here I show how.

How to make sure that some code executes whether or not an exception is thrown

You can nest try..catch blocks to handle exceptions that occur in the catch block of an exception handler!

How to handle an exception only when a certain condition is met

Step through your code and watch variables with Visual Studio

You can try out bits of C# code without having to write and compile an entire program using the C# interactive console. Here I show you how to get started with this.

The basics of error-handling and debugging

In the final step we look at collections and dictionaries – then start work on programming a game

The .NET framework supplies strongly-typed ‘generic’ collection classes which comes with lots of useful methods to add, remove and locate objects in the collection. 

Dictionaries are lists of values that can be indexed with a ‘key’ rather than a numeric index indication a position in the list.

C# lets you define ‘virtual’ methods that can be ‘overridden’ by methods of the same name in descendant classes. 

Let’s see how to use C# classes and techniques to write an exploring game

It may be a text-based game but it needs a graphical user interface!

Where did adventure games come from, anyway?

So how does the player interact with the game?

Now let’s look at the classes in my Adventure Game project. 

How can we save and restore all those objects?

Let’s see if how to use a Dictionary instead of a List to store the Room objects of the game.

Subclassed Dictionaries can be serialized. But you need to create a special constructor.

In this step we covered collections and dictionaries. I explained virtual and overridden methods. And finally I provided a reasonably complicated sample project – an adventure game. 

Well, that’s it. We’ve come to the end of the course.