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Head First C#, 2nd Edition

Book Description

You want to learn C# programming, but you're not sure you want to suffer through another tedious technical book. You're in luck: Head First C# introduces this language in a fun, visual way. You'll quickly learn everything from creating your first program to learning sophisticated coding skills with C# 4.0, Visual Studio 2010 and .NET 4, while avoiding common errors that frustrate many students.

The second edition offers several hands-on labs along the way to help you build and test programs using skills you've learned up to that point. In the final lab, you'll put everything together. From objects to garbage collection and from exceptions to interactions, you'll learn C# in a way that engages and entertains your brain. Here are a few of the topics you'll learn:

  • Start by building a useful application with pre-built components in Visual Studio 2010
  • Discover how objects work, using real-world examples
  • Store numbers, text, and other basic data types using primitives
  • Save complex data in files and databases with great C# tools
  • Build intuitive and easy-to-use interfaces by following simple rules
  • Design your code to catch exceptions -- things you don't expect
  • Develop good programming habits, such as refactoring code and applying unit tests
  • Learn how web services put your programs in touch with the rest of the world
  • Make it easy for other people to install your software

Table of Contents

  1. Head First C#
  2. Dedication
  3. A Note Regarding Supplemental Files
  4. Advance Praise for Head First C#
  5. Praise for other Head First books
  7. How to Use this Book: Intro
    1. Who is this book for?
      1. Who should probably back away from this book?
    2. We know what you’re thinking
    3. And we know what your brain is thinking
    4. Metacognition: thinking about thinking
    5. Here’s what WE did
    6. Here’s what YOU can do to bend your brain into submission
    7. What you need for this book
    8. Read me
    9. The technical review team
    10. Acknowledgments
    11. Safari® Books Online
  8. 1. Get Productive with C#: Visual Applications, in 10 minutes or less
    1. Why you should learn C#
      1. Here’s what the IDE automates for you...
      2. What you get with Visual Studio and C#...
    2. C# and the Visual Studio IDE make lots of things easy
    3. Help the CEO go paperless
    4. Get to know your users’ needs before you start building your program
    5. Here’s what you’re going to build
    6. What you do in Visual Studio...
    7. What Visual Studio does for you...
    8. Develop the user interface
    9. Visual Studio, behind the scenes
    10. Add to the auto-generated code
    11. You can already run your application
    12. Where are my files?
    13. Here’s what we’ve done so far
      1. .NET Visual Objects
    14. We need a database to store our information
    15. The IDE created a database
    16. SQL is its own language
    17. Creating the table for the Contact List
    18. The blanks on the contact card are columns in our People table
    19. Finish building the table
    20. Insert your card data into the database
    21. Connect your form to your database objects with a data source
    22. Add database-driven controls to your form
    23. Good programs are intuitive to use
    24. Test drive
      1. The IDE builds first, then runs
    25. How to turn YOUR application into EVERYONE’S application
    26. Give your users the application
    27. You’re NOT done: test your installation
    28. You’ve built a complete data-driven application
  9. 2. It’s All Just Code: Under the hood
    1. When you’re doing this...
    2. ...the IDE does this
    3. Where programs come from
      1. Every program starts out as source code files
      2. The .NET Framework gives you the right tools for the job
      3. Build the program to create an executable
      4. Your program runs inside the CLR
    4. The IDE helps you code
    5. When you change things in the IDE, you’re also changing your code
      1. Wait, wait! What did that say?
    6. Anatomy of a program
      1. Let’s take a closer look at your code
    7. Your program knows where to start
    8. You can change your program’s entry point
      1. So what happened?
    9. Two classes can be in the same namespace
    10. Your programs use variables to work with data
      1. Declare your variables
      2. Variables vary
      3. You have to assign values to variables before you use them
      4. A few useful types
    11. C# uses familiar math symbols
    12. Use the debugger to see your variables change
    13. Loops perform an action over and over
      1. Use a code snippet to write simple for loops
    14. Time to start coding
      1. Add statements to show a message
    15. if/else statements make decisions
    16. Set up conditions and see if they’re true
      1. Use logical operators to check conditions
      2. Set a variable and then check its value
      3. Add another conditional test
      4. Add loops to your program
  10. 3. Objects: Get Oriented!: Making code make sense
    1. How Mike thinks about his problems
    2. How Mike’s car navigation system thinks about his problems
    3. Mike’s Navigator class has methods to set and modify routes
      1. Some methods have a return value
    4. Use what you’ve learned to build a program that uses a class
      1. So what did you just build?
    5. Mike gets an idea
      1. He could create three different Navigator classes...
    6. Mike can use objects to solve his problem
    7. You use a class to build an object
      1. An object gets its methods from its class
    8. When you create a new object from a class, it’s called an instance of that class
    9. A better solution...brought to you by objects!
      1. Theory and practice
      2. A little advice for the code exercises
    10. An instance uses fields to keep track of things
      1. Methods are what an object does. Fields are what the object knows
    11. Let’s create some instances!
    12. Thanks for the memory
      1. Let’s take a closer look at what happened here
    13. What’s on your program’s mind
    14. You can use class and method names to make your code intuitive
    15. Give your classes a natural structure
      1. Let’s build a class diagram
    16. Class diagrams help you organize your classes so they make sense
    17. Build a class to work with some guys
    18. Create a project for your guys
    19. Build a form to interact with the guys
    20. There’s an easier way to initialize objects
  11. 4. Types and References: It’s 10:00. Do you know where your data is?
    1. The variable’s type determines what kind of data it can store
    2. A variable is like a data to-go cup
    3. 10 pounds of data in a 5 pound bag
    4. Even when a number is the right size, you can’t just assign it to any variable
      1. So what happened?
    5. When you cast a value that’s too big, C# will adjust it automatically
    6. C# does some casting automatically
    7. When you call a method, the arguments must be compatible with the types of the parameters
    8. Combining = with an operator
    9. Objects use variables, too
    10. Refer to your objects with reference variables
    11. References are like labels for your object
    12. If there aren’t any more references, your object gets garbage-collected
    13. Multiple references and their side effects
    14. Two references means TWO ways to change an object’s data
    15. A special case: arrays
      1. Use each element in an array like it is a normal variable
    16. Arrays can contain a bunch of reference variables, too
    17. Welcome to Sloppy Joe’s Budget House o’ Discount Sandwiches!
    18. Objects use references to talk to each other
    19. Where no object has gone before
    20. Build a typing game
  12. I. C# Lab: A Day at the Races
    1. 5. Encapsulation: Keep your privates... private
      1. Kathleen is an event planner
      2. What does the estimator do?
      3. Kathleen’s Test Drive
      4. Each option should be calculated individually
      5. It’s easy to accidentally misuse your objects
      6. Encapsulation means keeping some of the data in a class private
      7. Use encapsulation to control access to your class’s methods and fields
      8. But is the realName field REALLY protected?
      9. Private fields and methods can only be accessed from inside the class
        1. Encapsulation makes your classes...
        2. Mike’s navigator program could use better encapsulation
        3. Think of an object as a black box
      10. Encapsulation keeps your data pristine
        1. A quick example of encapsulation
      11. Properties make encapsulation easier
      12. Build an application to test the Farmer class
      13. Use automatic properties to finish the class
        1. Fully encapsulate the Farmer class
      14. What if we want to change the feed multiplier?
      15. Use a constructor to initialize private fields
    2. 6. Inheritance: Your object’s family tree
      1. Kathleen does birthday parties, too
      2. We need a BirthdayParty class
        1. Here’s what we’re going to do:
      3. Build the Party Planner version 2.0
      4. One more thing...can you add a $100 fee for parties over 12?
      5. When your classes use inheritance, you only need to write your code once
        1. Dinner parties and birthday parties are both parties
      6. Build up your class model by starting general and getting more specific
      7. How would you design a zoo simulator?
      8. Use inheritance to avoid duplicate code in subclasses
      9. Different animals make different noises
        1. Think about what you need to override
      10. Think about how to group the animals
      11. Create the class hierarchy
      12. Every subclass extends its base class
        1. C# always calls the most specific method
      13. Use a colon to inherit from a base class
      14. We know that inheritance adds the base class fields, properties, and methods to the subclass...
        1. ...but some birds don’t fly!
      15. A subclass can override methods to change or replace methods it inherited
      16. Any place where you can use a base class, you can use one of its subclasses instead
      17. A subclass can hide methods in the superclass
        1. Hiding methods versus overriding methods
        2. Use different references to call hidden methods
        3. Use the new keyword when you’re hiding methods
      18. Use the override and virtual keywords to inherit behavior
      19. A subclass can access its base class using the base keyword
      20. When a base class has a constructor, your subclass needs one, too
        1. The base class constructor is executed before the subclass constructor
      21. Now you’re ready to finish the job for Kathleen!
      22. Build a beehive management system
      23. First you’ll build the basic system
      24. Use inheritance to extend the bee management system
    3. 7. Interfaces and Abstract Classes: Making classes keep their promises
      1. Let’s get back to bee-sics
        1. Lots of things are still the same
      2. We can use inheritance to create classes for different types of bees
      3. An interface tells a class that it must implement certain methods and properties
      4. Use the interface keyword to define an interface
      5. Now you can create an instance of NectarStinger that does both jobs
      6. Classes that implement interfaces have to include ALL of the interface’s methods
      7. Get a little practice using interfaces
      8. You can’t instantiate an interface, but you can reference an interface
      9. Interface references work just like object references
      10. You can find out if a class implements a certain interface with “is”
      11. Interfaces can inherit from other interfaces
        1. Any class that implements an interface that inherits from IWorker must implement its methods and properties
      12. The RoboBee 4000 can do a worker bee’s job without using valuable honey
      13. is tells you what an object implements, as tells the compiler how to treat your object
      14. A CoffeeMaker is also an Appliance
      15. Upcasting works with both objects and interfaces
      16. Downcasting lets you turn your appliance back into a coffee maker
        1. When downcasting fails, as returns null
      17. Upcasting and downcasting work with interfaces, too
      18. There’s more than just public and private
      19. Access modifiers change visibility
      20. Some classes should never be instantiated
      21. An abstract class is like a cross between a class and an interface
      22. Like we said, some classes should never be instantiated
        1. Solution: use an abstract class
      23. An abstract method doesn’t have a body
        1. The four principles of object oriented programming
      24. Polymorphism means that one object can take many different forms
        1. Keep your eyes open for polymorphism in the next exercise!
    4. 8. Enums and Collections; Storing lots of data
      1. Strings don’t always work for storing categories of data
      2. Enums let you work with a set of valid values
      3. Enums let you represent numbers with names
      4. We could use an array to create a deck of cards...
        1. ...but what if you wanted to do more?
      5. Arrays are hard to work with
      6. Lists make it easy to store collections of...anything
      7. Lists are more flexible than arrays
      8. Lists shrink and grow dynamically
      9. Generics can store any type
      10. Collection initializers work just like object initializers
      11. Let’s create a List of Ducks
        1. Here’s the initializer for your List of Ducks
      12. Lists are easy, but SORTING can be tricky
        1. You could sort a list of ducks by size...
        2. ...or by kind
        3. Lists know how to sort themselves
      13. IComparable<Duck> helps your list sort its ducks
        1. An object’s CompareTo() method compares it to another object
      14. Use IComparer to tell your List how to sort
      15. Create an instance of your comparer object
        1. Multiple IComparer implementations, multiple ways to sort your objects
      16. IComparer can do complex comparisons
      17. Overriding a ToString() method lets an object describe itself
      18. Update your foreach loops to let your Ducks and Cards print themselves
        1. Add a ToString() method to your Card object, too
      19. You can upcast an entire list using IEnumerable
        1. Combine your birds into a single list
      20. You can build your own overloaded methods
      21. Use a dictionary to store keys and values
      22. The Dictionary Functionality Rundown
        1. Your key and value can be different types
      23. Build a program that uses a Dictionary
      24. And yet MORE collection types...
        1. Generic collections are an important part of the .NET Framework
      25. A queue is FIFO—First In, First Out
      26. A stack is LIFO—Last In, First Out
  13. II. C# Lab: The Quest
    1. 9. Reading and Writing Files: Save the byte array, save the world
      1. .NET uses streams to read and write data
      2. Different streams read and write different things
        1. Things you can do with a stream
      3. A FileStream reads and writes bytes to a file
      4. How to write text to a file in 3 simple steps
      5. The Swindler launches another diabolical plan
      6. Reading and writing using two objects
      7. Data can go through more than one stream
      8. Use built-in objects to pop up standard dialog boxes
        1. ShowDialog() pops up a dialog box
      9. Dialog boxes are just another .NET control
      10. Dialog boxes are objects, too
      11. Use the built-in File and Directory classes to work with files and directories
        1. Things you can do with a File
        2. Things you can do with a Directory
      12. Use file dialogs to open and save files (all with just a few lines of code)
      13. IDisposable makes sure your objects are disposed of properly
      14. Avoid file system errors with using statements
        1. Use multiple using statements for multiple objects
      15. Trouble at work
        1. You can help Brian out by building a program to manage his excuses
      16. Writing files usually involves making a lot of decisions
      17. Use a switch statement to choose the right option
      18. Use a switch statement to let your deck of cards read from a file or write itself out to one
      19. Add an overloaded Deck() constructor that reads a deck of cards in from a file
      20. What happens to an object when it’s serialized?
      21. But what exactly IS an object’s state? What needs to be saved?
      22. When an object is serialized, all of the objects it refers to get serialized, too...
      23. Serialization lets you read or write a whole object all at once
        1. You’ll need a BinaryFormatter object
        2. Now just create a stream and read or write your objects
      24. If you want your class to be serializable, mark it with the [Serializable] attribute
      25. Let’s serialize and deserialize a deck of cards
      26. .NET uses Unicode to store characters and text
      27. C# can use byte arrays to move data around
      28. Use a BinaryWriter to write binary data
        1. Use BinaryReader to read the data back in
      29. You can read and write serialized files manually, too
      30. Find where the files differ, and use that information to alter them
      31. Working with binary files can be tricky
      32. Use file streams to build a hex dumper
        1. How to make a hex dump
        2. Working with hex
      33. StreamReader and StreamWriter will do just fine (for now)
      34. Use Stream.Read() to read bytes from a stream
    2. 10. Exception Handling: Putting out fires gets old
      1. Brian needs his excuses to be mobile
        1. But the program isn’t working!
      2. When your program throws an exception, .NET generates an Exception object
      3. Brian’s code did something unexpected
      4. All exception objects inherit from Exception
      5. The debugger helps you track down and prevent exceptions in your code
        1. Put your IDE into Expert mode to expand the Debug toolbar
        2. Toggle hexadecimal mode on and off
      6. Use the IDE’s debugger to ferret out exactly what went wrong in the Excuse Manager
      7. Uh oh—the code’s still got problems...
      8. Handle exceptions with try and catch
      9. What happens when a method you want to call is risky?
      10. Use the debugger to follow the try/catch flow
      11. If you have code that ALWAYS should run, use a finally block
      12. Use the Exception object to get information about the problem
      13. Use more than one catch block to handle multiple types of exceptions
      14. One class throws an exception, another class catches the exception
      15. Bees need an OutOfHoney exception
      16. An easy way to avoid a lot of problems: using gives you try and finally for free
      17. Exception avoidance: implement IDisposable to do your own cleanup
      18. The worst catch block EVER: catch-all plus comments
        1. You should handle your exceptions, not bury them
      19. Temporary solutions are OK (temporarily)
      20. A few simple ideas for exception handling
      21. Brian finally gets his vacation...
        1. ...and things are looking up back home!
    3. 11. Events and Delegates: What your code does when you’re not looking
      1. Ever wish your objects could think for themselves?
      2. But how does an object KNOW to respond?
      3. When an EVENT occurs...objects listen
        1. Want to DO SOMETHING with an event? You need an event handler
      4. One object raises its event, others listen for it...
      5. Then, the other objects handle the event
      6. Connecting the dots
        1. Use a standard name when you add a method to raise an event
      7. The IDE creates event handlers for you automatically
      8. Generic EventHandlers let you define your own event types
        1. Use implicit conversion by leaving out the new keyword and the event type
      9. The forms you’ve been building all use events
      10. One event, multiple handlers
      11. Connecting event senders with event receivers
        1. “My people will get in touch with your people.”
      12. A delegate STANDS IN for an actual method
        1. A delegate adds a new type to your project
      13. Delegates in action
      14. An object can subscribe to an event...
        1. ...but that’s not always a good thing!
      15. Use a callback to control who’s listening
      16. A callback is just a way to use delegates
    4. 12. Review and Preview: Knowledge, power, and building cool stuff
      1. You’ve come a long way, baby
      2. We’ve also become beekeepers
        1. But we can do a lot better now...
      3. The beehive simulator architecture
      4. Building the beehive simulator
      5. Life and death of a flower
      6. Now we need a Bee class
      7. P. A. H. B. (Programmers Against Homeless Bees)
      8. The hive runs on honey
      9. Filling out the Hive class
      10. The hive’s Go() method
      11. We’re ready for the World
        1. The World object keeps everything Go()ing
      12. We’re building a turn-based system
      13. Here’s the code for World
      14. Giving the bees behavior
      15. The main form tells the world to Go()
      16. We can use World to get statistics
      17. Timers fire events over and over again
      18. The timer’s using an event handler behind the scenes
      19. Add a timer to the simulator
      20. Test drive
      21. Let’s work with groups of bees
      22. A collection collects...DATA
      23. LINQ makes working with data in collections and databases easy
      24. Test drive (Part 2)
      25. One final challenge: Open and Save
    5. 13. Controls and Graphics: Make it pretty
      1. You’ve been using controls all along to interact with your programs
      2. Form controls are just objects
      3. Use controls to animate the beehive simulator
      4. Add a renderer to your architecture
      5. The renderer draws everything in the world on the two forms
        1. The simulator renders the world after each frame
      6. Controls are well suited for visual display elements
      7. Build your first animated control
        1. We want a control in the toolbox
      8. BeeControl is LIKE a PictureBox...so let’s start by INHERITING from PictureBox
      9. Create a button to add the BeeControl to your form
      10. Your controls need to dispose their controls, too!
      11. A UserControl is an easy way to build a control
      12. Your simulator’s renderer will use your BeeControl to draw animated bees on your forms
      13. Add the hive and field forms to the project
        1. Figure out where your locations are
      14. Build the renderer
      15. Now connect the main form to your two new forms, HiveForm and FieldForm
      16. Test drive...ahem...buzz
      17. Looks great, but something’s not quite right...
      18. Let’s take a closer look at those performance issues
      19. You resized your Bitmaps using a Graphics object
        1. Let’s see image resizing in action
      20. Your image resources are stored in Bitmap objects
        1. Then each Bitmap is drawn to the screen
        2. The bigger they are...
      21. Use System.Drawing to TAKE CONTROL of graphics yourself
      22. A 30-second tour of GDI+ graphics
      23. Use graphics to draw a picture on a form
      24. Graphics can fix our transparency problem...
      25. Use the Paint event to make your graphics stick
      26. A closer look at how forms and controls repaint themselves
      27. Double buffering makes animation look a lot smoother
      28. Double buffering is built into forms and controls
        1. Overhaul the beehive simulator
      29. Use a Graphics object and an event handler for printing
      30. PrintDocument works with the print dialog and print preview window objects
        1. Use e.HasMorePages to print multipage documents
    6. 14. Captain Amazing: The Death of the Object
      1. Your last chance to DO something... your object’s finalizer
      2. When EXACTLY does a finalizer run?
        1. You can SUGGEST to .NET that it’s time to collect the garbage
      3. Dispose() works with using, finalizers work with garbage collection
      4. Finalizers can’t depend on stability
      5. Make an object serialize itself in its Dispose()
      6. A struct looks like an object...
      7. ...but isn’t an object
      8. Values get copied; references get assigned
      9. Structs are value types; objects are reference types
        1. Here’s what happened...
      10. The stack vs. the heap: more on memory
      11. Use out parameters to make a method return more than one value
      12. Pass by reference using the ref modifier
      13. Use optional parameters to set default values
      14. Use nullable types when you need nonexistent values
      15. Nullable types help you make your programs more robust
      16. Captain Amazing...not so much
      17. Extension methods add new behavior to EXISTING classes
      18. Extending a fundamental type: string
    7. 15. LINQ: Get control of your data
      1. An easy project...
      2. ...but the data’s all over the place
      3. LINQ can pull data from multiple sources
      4. .NET collections are already set up for LINQ
      5. LINQ makes queries easy
      6. LINQ is simple, but your queries don’t have to be
      7. LINQ is versatile
      8. LINQ can combine your results into groups
      9. Combine Jimmy’s values into groups
      10. Use join to combine two collections into one query
      11. Jimmy saved a bunch of dough
      12. Connect LINQ to a SQL database
      13. Use a join query to connect Starbuzz and Objectville
  14. III. C# Lab: Invaders
    1. A. Leftovers: The top 11 things we wanted to include in this book
      1. #1. The Basics
        1. ...more basics...
      2. #2. Namespaces and assemblies
        1. ...so what did I just do?
        2. Why you added public to the class declarations in Chapter 13
      3. #3. Use BackgroundWorker to make your UI responsive
      4. #4. The Type class and GetType()
      5. #5. Equality, IEquatable, and Equals()
      6. #6. Using yield return to create enumerable objects
      7. #7. Refactoring
        1. Extract a method
        2. Rename a variable
        3. Consolidate a conditional expression
      8. #8. Anonymous types, anonymous methods, and lambda expressions
      9. #9. Serializing data using DataContractSerializer
      10. #10. LINQ to XML
        1. Save and load XML files
        2. Query your data
        3. Read data from an RSS feed
      11. #11. Windows Presentation Foundation
      12. Did you know that C# and the .NET Framework can...
  15. Index
  16. About the Authors
  17. Copyright