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.NET Framework 4
How to: Read Text from a File

The following code examples show how to read text from a text file. The second example notifies you when the end of the file is detected. This functionality can also be achieved by using the ReadAllLines or ReadAllText methods.

Visual Basic
Imports System
Imports System.IO

Class Test
    Public Shared Sub Main()
        Try
            ' Create an instance of StreamReader to read from a file.
            ' The using statement also closes the StreamReader.
            Using sr As New StreamReader("TestFile.txt")
                Dim line As String
                ' Read and display lines from the file until the end of
                ' the file is reached.
                Do
                    line = sr.ReadLine()
                    If Not (line Is Nothing) Then
                        Console.WriteLine(line)
                    End If
                Loop Until line Is Nothing
            End Using
        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);
        }
    }
}
Visual C++
using namespace System;
using namespace System::IO;

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

int main()
{
    Test::Main();
}
Visual Basic
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
        Using sr As StreamReader = File.OpenText(FILE_NAME)
            Dim input As String
            Do
                input = sr.ReadLine()
                If Not (input Is Nothing) Then
                    Console.WriteLine(input)
                End If
            Loop Until input Is Nothing
            Console.WriteLine ("The end of the stream has been reached.")
        End Using
    End Sub
End Class
C#
using System;
using System.IO;

public class TextFromFile
{
    private const string FILE_NAME = "MyFile.txt";

    public static void Main()
    {
        if (!File.Exists(FILE_NAME))
        {
            Console.WriteLine("{0} does not exist.", FILE_NAME);
            return;
        }
        using (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.");
        }
    }
}
Visual C++
using namespace System;
using namespace System::IO;

public ref class TextFromFile
{
private:
    static String^ FILE_NAME = "MyFile.txt";

public:
    static void Main()
    {
        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()) != nullptr)
        {
            Console::WriteLine(input);
        }
        Console::WriteLine ("The end of the stream has been reached.");
        sr->Close();
    }
};

int main()
{
    TextFromFile::Main();
}

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.

NoteNote

Visual Basic users may choose to use the methods and properties provided by the FileSystem class for file I/O.

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