In this tutorial you will learn about Access and Manipulate Data, Working with Disk Files, Browsing for Files, Streams and Backing Stores, Using the FileStream Class, Using the StreamReader and StreamWriter Classes, Using the BinaryReader and BinaryWriter Classes.

Working with Disk Files

Temporary storage of data as in the illustrations above is not the optimal solution. Persistent data storage is a file having a collection of bytes and is stored as data streams. All read write operations to these data steams can be done with ease in the circumstances. In the following illustration we shall see how read write operations can be performed on persistent data storage.

Browsing For Files

The System.IO.Directory class can be used for typical operations such as copying, moving, renaming, creating and deleting directories. This is a static class and therefore is efficient in the performance of single operations. This class can be used to perform operations relating to browsing for files, The System.IO.FileInfo.Name method of this class used to see the files in the directory. The System.IO.Directory.GetDirectories or System.DirectoryInfo.GetDirectories methods enable users see the sub directories in a the directory. Let us understand the issue by the following example.

1. Create a new windows application in the Visual Basic Express and
   
2. Give the name of the project as FileBrowse1.
   
3. To the form Form1 add two Labels, a TextBox , a CheckBox, and two Buttons.
   
4. Arrange the controls and name them as shown in the screenshot shown below:
   

Now add the necessary code to the application. The code for the application is shown below:

Click here to veiw sample code

Now press F5 to execute the application. In the window type the directory name that we want to browse and also use the check box to specify if we want to view the file names or not. Now click the button Browse to view the file names and the directory names. The outputs generated for both with and without the check box selected are shown below:

Streams

Stream is the abstract base class of all streams. A stream is an abstraction of a sequence of bytes, such as a file, an input/output device, an inter-process communication pipe, or TCP/IP socket. The stream class and its derived classes provide generic view of these different types of input and output, isolating the programmer from the specific details of the operating system and the underlying devices.

Streams are concerned with three fundamental operations:

1.2.3.Depending on the underlying data source or repository, streams might support only some of the several capabilities. An application may query a stream for its capabilities by using the System.IO.Stream.CanRead, System.IO.Stream.CanWrite, and System.IO.Stream.CanSeek properties.