Head First C#, 5th Edition

Chapter 10. Reading and Writing Files Save the last byte for me

Sometimes it pays to be persistent.

So far, all of your programs have been pretty short-lived. They fire up, run for a while, and shut down. But that’s not always enough, especially when you’re dealing with important information. You need to be able to save your work. In this chapter, we’ll look at how to write data to a file, and then how to read that information back in from a file. You’ll learn about streams, and how to store your objects in files with serialization, and get down to the actual bits and bytes of hexadecimal, Unicode, and binary data.

.NET uses streams to read and write data

A stream is the .NET Framework’s way of getting data into and out of your program. Any time your program reads or writes a file, connects to another computer over a network, or generally does anything where it sends or receives bytes, you’re using streams. Sometimes you’re using streams directly, other times indirectly. Even when you’re using classes that don’t directly expose streams, under the hood they’re almost always using streams.

Let’s say you have a simple app that needs to read data from a file. A really basic way to do that is to use a Stream object.

And if your app needs to write data out to the file, it can use ...