C# 5.0 Programmer's Reference

444 ❘ CHAPTER 19 File System Objects
Finally this chapter explained techniques you can use to manage the recycle bin. Some of them are
fairly complex, but at least the FileIO.FileSystem class makes moving a file or directory into the
recycle reasonably simple.
So far the chapters in this book have explained how to do things locally on the user’s computer.
The next chapter explains how a program can move off of the local computer to download files
from the Internet.
Exercises
1. Write a program that lets the user select a directory and displays its creation, last access,
and last write times.
2. Write a program that lets the user select a file and displays its creation, last access, and last
write times. Let the user change the times and then set them for the file.
3. Write a program that lets the user get and set a file’s attributes. Use CheckBoxes to display
and let the user specify attributes.
4. Write a program that uses File.ReadAllText and File.WriteAllText to save and restore
the contents of a text file when it starts and stops. Compare your solution to the solution for
Exercise 18-3.
5. Write a program that sorts the lines in a file. (Hint: Use File.ReadAllLines to get the
lines, sort them, and then use File.WriteAllLines to write them back into the file.)
6. Write a program that lists the computer’s drives and whatever drive information is available
from the DriveInfo class.
7. Modify the program you wrote for Exercise 6 so that it displays sizes in KB, MB, GB, or
TB as appropriate.
8. Write a program that displays the name of the directory two levels higher than the directory
where the program is executing. What happens if you run the program near the top of the
directory hierarchy, for example, in C:\
9. Write a program that lets the user enter a directory path and a pattern. When the user clicks
the Search button, the program should search the directory and its subdirectories for files
matching the pattern.
10. Modify the program you wrote for Exercise 9 so that it shows the selected filenames (without
paths) and their sizes.
11. Write a program that uses a FileSystemWatcher to watch the directory where the program
is executing for changes. When a change occurs, the program should display the date and
time, the type of change, and the changing file’s name.
12. Write a program that lets the user enter a filename and then uses the FileIO class to move
the file into the recycle bin. (That’s all many programs need to do anyway. You can use the
recycle bin on your desktop to manage its contents.)
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