Reading Text from a File

Article
10/17/2014

The following code example shows a simple way to read text from a text file.

Imports System
Imports System.IO

Class Test
    Public Shared Sub Main()
        Try
            ' Create an instance of StreamReader to read from a file.
            Dim sr As StreamReader = New StreamReader("TestFile.txt")
            Dim line As String
            ' Read and display the lines from the file until the end 
            ' of the file is reached.
            Do
                line = sr.ReadLine()
                Console.WriteLine(Line)
            Loop Until line Is Nothing
            sr.Close()
        Catch E As Exception
            ' Let the user know what went wrong.
            Console.WriteLine("The file could not be read:")
            Console.WriteLine(E.Message)
        End Try
    End Sub
End Class

[C#]
using System;
using System.IO;

class Test 
{
    public static void Main() 
    {
        try 
        {
            // Create an instance of StreamReader to read from a file.
            // The using statement also closes the StreamReader.
            using (StreamReader sr = new StreamReader("TestFile.txt")) 
            {
                String line;
                // Read and display lines from the file until the end of 
                // the file is reached.
                while ((line = sr.ReadLine()) != null) 
                {
                    Console.WriteLine(line);
                }
            }
        }
        catch (Exception e) 
        {
            // Let the user know what went wrong.
            Console.WriteLine("The file could not be read:");
            Console.WriteLine(e.Message);
        }
    }
}

The following code example reads an entire file and notifies you when the end of the file is detected.

Option Explicit On 
Option Strict On
Imports System
Imports System.IO
Public Class TextFromFile
    Private Const FILE_NAME As String = "MyFile.txt"
    Public Shared Sub Main()
        If Not File.Exists(FILE_NAME) Then
            Console.WriteLine("{0} does not exist.", FILE_NAME)
            Return
        End If
        Dim sr As StreamReader = File.OpenText(FILE_NAME)
        Dim input As String
        input = sr.ReadLine()
        While Not input Is Nothing
            Console.WriteLine(input)
            input = sr.ReadLine()
        End While
        Console.WriteLine("The end of the stream has been reached.")
        sr.Close()
    End Sub
End Class

[C#]
using System;
using System.IO;
public class TextFromFile 
{
    private const string FILE_NAME = "MyFile.txt";
    public static void Main(String[] args) 
    {
        if (!File.Exists(FILE_NAME)) 
        {
            Console.WriteLine("{0} does not exist.", FILE_NAME);
            return;
        }
        StreamReader sr = File.OpenText(FILE_NAME);
        String input;
        while ((input=sr.ReadLine())!=null) 
        {
            Console.WriteLine(input);
        }
        Console.WriteLine ("The end of the stream has been reached.");
        sr.Close();
    }
}

This code creates a StreamReader that points to MyFile.txt through a call to File.OpenText. StreamReader.ReadLine returns each line as a string. When there are no more characters to read, a message is displayed to that effect, and the stream is closed.

Reading Text from a File

See Also

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