下面的代碼示例顯示從文本文件讀取文本的簡單方法。

[Visual Basic]
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);
        }
    }
}

下面的代碼示例讀取整個文件，并在檢測到文件尾時發出通知。

[Visual Basic]
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();
    }
}

此代碼通過調用 File.OpenText 創建一個指向 MyFile.txt 的 StreamReader。StreamReader.ReadLine 將每一行都返回為一個字符串。當沒有要讀取的字符時，一條消息顯示該情況，然后流關閉。