Classes to Work with Files and Directories

In the design section of the chapter we mentioned that the .NET Framework provides quite a lot of classes to easily manipulate and retrieve information about the file system's items. The System.IO namespace contains all the classes that have to do with the IO operations for any backing store, and some classes that allow us to do advanced stuff such as monitoring the file system and listening for changes (this was pretty hard to do with the Windows API). Since we'll use some of these classes throughout the chapter, it's worth giving a brief description of the most used IO classes:

 

Class	Description
Directory	Provides static (shared) methods for enumerating directories and logical drives, creating/deleting/moving directories and files, and retrieving/editing things like the creation date or the last access date.
DirectoryInfo	Used to work with a specified directory and its subdirectories.
File	Provides static methods for working with files: this includes opening or checking the existence of a file, and appending text data to a file.
FileInfo	Used to work with a specific file.
Path	Performs operations such as extracting the root or the file name from the specified path or combining two path strings.
FileSystemWatcher	Monitors the file system and raises events to handle changes.
Stream	Base class used to read from and write a backing store, such as the file system or network.
StreamReader	Used in conjunction with a stream to read characters from a backing store.
StreamWriter	Used in conjunction with a stream to write characters to a backing store.
TextReader	Abstract class used to define methods for reading characters from any source (backing store, string, and so on).
TextWriter	Abstract class used to define methods for writing characters to any source (backing store, string, and so on).
BinaryReader	Used to read primitive types such as string, integer, and boolean from a stream.
BinaryWriter	Used to write primitive types such as string, integer, and boolean to a stream.
FileStream	Used to read and write data in the file system.
MemoryStream	Used to read and write data in a memory buffer.

 

For a more complete listing of the System.IO namespace's classes and their methods, you can refer to Professional ASP.NET (Wrox Press, ISBN 1-861004-88-5) or Professional C# (Wrox Press, ISBN 1-861004-99-0). We will look at some of the classes described above in action.

Header and Footer Controls

We start our coding with the module-specific controls – in other words the header and the footer. Create a new user control named Header.ascx, and write the following code in the HTML tab of the IDE:

 

 

This is simply HTML code (no need to use ASP.NET controls if we don't need to dynamically program them) that creates a title bar and a hyperlink image. This image links to an anchor placed at the bottom of the page, providing a quick way to scroll the page. Note that we associate the MenuTable style to the HTML table. In Chapter 3 we created a stylesheet, ThePhile.css, and began to define styles for use throughout the site. We have now added several new style definitions that we need for our FileManager module. We won't go into the code here – the modified file is available in code download, and you should refer back to Chapter 3 for an explanation of how cascading styles work. This stylesheet is imported by the page that will use this custom control.

 

The only modification we need to make in the code-behind is to change the namespace to Wrox.WebModules.FileManager.Web.Controls.User, which follows the conventions we discussed in Chapter 2.

 

The footer control, similarly, defines a link to jump to the top of the page. It contains an anchor that links from the icon to the header control. Here's the code for Footer.ascx:

 

Also, modify the namespace in the code-behind for Footer.ascx in exactly the same way as we did for the header control. In this particular module the header and footer controls are not really necessary, since we have only two pages, but it's a good practice to build them now, as we might want to add new features (and thus other pages) in the future.