The basics of reading and writing files

This lesson covers reading and writing files in VB.NET, with the aim of saving and loading text from a program.

File.WriteAllText() writes a string to a file and File.ReadAllText() reads one back. Putting Imports System.IO at the top lets you use these under their short names.

The sample code saves the contents of a memo with File.WriteAllText("memo.txt", ...) and reads the same file straight back with File.ReadAllText("memo.txt"). Note the line break inserted with vbLf.

A common early stumble is handling a missing file or missing write permission. Real applications are expected to wrap file operations in Try...Catch.

In professional work, file handling is needed in almost every application — saving configuration, writing to a log, reading CSV data.

📖 Reference code

Imports System.IO

Module Program
    Sub Main()
        File.WriteAllText("memo.txt", "Hello" & vbLf & "This is line 2")
        Dim content As String = File.ReadAllText("memo.txt")
        Console.WriteLine(content)
    End Sub
End Module

✍️ Your code

Type your code, then press "Run"

🧪 This site can't compile or run VB.NET directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).