Part 3.8File handling

VB.NET offers several ways to read a file. Often, the more old fashioned yet more efficient method of reading a file line by line, is seen as the preferrable way of doing this.

Reading a file using a stream

A stream is what is basically a bunch of bytes that a file system provides to a subsystem in chunks. VB.NET, like many languages, provides the StreamReader object to work with file reading.

The following example reads a text file line by line and write the line number of the line and the line contents to the console:

Dim line_no As Integer = 1
Dim line As String
Dim reader As StreamReader = New StreamReader("file.txt")

line = reader.ReadLine

'Keep looping until line becomes nothing
Do Until (line Is Nothing)
  'Write the line and line number to console
  Console.WriteLine(line_no & & line)
  line_no = line_no + 1
  line = reader.ReadLine
Loop