Visual Basic 2005: A Developer's Notebook

Read and Write Files

If you need to work with text files or raw binary data, VB 2005 provides a new solution that bypasses the lower-level classes of System.IO for small files. Now you can read and write text in a single atomic operation using the My.Computer.FileSystem object. Best of all, you no longer need to create streams, track your position, or clean up afterward.

Note

At last, a way to read and write files without the complexities of streams and stream readers.

How do I do that?

The My.Computer.FileIO object provides the absolute quickest way to read or write the contents of a file. Its secret lies in a few self-contained methods. These include:

ReadAllText( )

Reads the content of a text file and returns it as a single string.

ReadAllBytes( )

Reads the content of any file and returns it as an array of bytes.

WriteAllText( )

Writes text as a string to a file in one atomic operation. You can either add to an existing file or create a new file, depending on whether you supply True or False for the Boolean append parameter.

WriteAllBytes( )

Writes a byte array to a file in a single operation. You can either add to an existing file or create a new file, depending on whether you supply True or False for the Boolean append parameter.

Example 5-4 creates a simple text file and then reads it back into memory.

Example 5-4. Write a file in one step and read a file in one step

Imports System.IO Module FileReadAndWrite Public Sub Main( ) Dim Text As String = "This is line 1" & _ vbNewLine & "This ...