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StreamReader Class
 
System_CAPS_noteNote

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Implements a TextReader that reads characters from a byte stream in a particular encoding.

To browse the .NET Framework source code for this type, see the Reference Source.

Namespace:   System.IO
Assembly:  mscorlib (in mscorlib.dll)

SystemObject
   SystemMarshalByRefObject
     System.IOTextReader
      System.IOStreamReader

[SerializableAttribute]
[ComVisibleAttribute(true)]
public class StreamReader : TextReader
[SerializableAttribute]
[ComVisibleAttribute(true)]
public ref class StreamReader : TextReader
[<SerializableAttribute>]
[<ComVisibleAttribute(true)>]
type StreamReader = 
    class
        inherit TextReader
    end
<SerializableAttribute>
<ComVisibleAttribute(True)>
Public Class StreamReader
	Inherits TextReader
NameDescription
System_CAPS_pubmethod StreamReader

Initializes a new instance of the StreamReader class for the specified stream.

System_CAPS_pubmethod StreamReader

Initializes a new instance of the StreamReader class for the specified stream, with the specified byte order mark detection option.

System_CAPS_pubmethod StreamReader

Initializes a new instance of the StreamReader class for the specified stream, with the specified character encoding.

System_CAPS_pubmethod StreamReader

Initializes a new instance of the StreamReader class for the specified stream, with the specified character encoding and byte order mark detection option.

System_CAPS_pubmethod StreamReader

Initializes a new instance of the StreamReader class for the specified stream, with the specified character encoding, byte order mark detection option, and buffer size.

System_CAPS_pubmethod StreamReader

Initializes a new instance of the StreamReader class for the specified stream based on the specified character encoding, byte order mark detection option, and buffer size, and optionally leaves the stream open.

System_CAPS_pubmethod StreamReader

Initializes a new instance of the StreamReader class for the specified file name.

System_CAPS_pubmethod StreamReader

Initializes a new instance of the StreamReader class for the specified file name, with the specified byte order mark detection option.

System_CAPS_pubmethod StreamReader

Initializes a new instance of the StreamReader class for the specified file name, with the specified character encoding.

System_CAPS_pubmethod StreamReader

Initializes a new instance of the StreamReader class for the specified file name, with the specified character encoding and byte order mark detection option.

System_CAPS_pubmethod StreamReader

Initializes a new instance of the StreamReader class for the specified file name, with the specified character encoding, byte order mark detection option, and buffer size.

NameDescription
System_CAPS_pubproperty

Returns the underlying stream.

System_CAPS_pubproperty

Gets the current character encoding that the current StreamReader object is using.

System_CAPS_pubproperty

Gets a value that indicates whether the current stream position is at the end of the stream.

NameDescription
System_CAPS_pubmethod Close

Closes the StreamReader object and the underlying stream, and releases any system resources associated with the reader.(Overrides TextReaderClose.)

System_CAPS_pubmethod CreateObjRef

Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.(Inherited from MarshalByRefObject.)

System_CAPS_pubmethod DiscardBufferedData

Clears the internal buffer.

System_CAPS_pubmethod Dispose

Releases all resources used by the TextReader object.(Inherited from TextReader.)

System_CAPS_protmethod Dispose

Closes the underlying stream, releases the unmanaged resources used by the StreamReader, and optionally releases the managed resources.(Overrides TextReaderDispose.)

System_CAPS_pubmethod Equals

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethod Finalize

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethod GetHashCode

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethod GetLifetimeService

Retrieves the current lifetime service object that controls the lifetime policy for this instance.(Inherited from MarshalByRefObject.)

System_CAPS_pubmethod GetType

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethod InitializeLifetimeService

Obtains a lifetime service object to control the lifetime policy for this instance.(Inherited from MarshalByRefObject.)

System_CAPS_protmethod MemberwiseClone

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_protmethod MemberwiseClone

Creates a shallow copy of the current MarshalByRefObject object.(Inherited from MarshalByRefObject.)

System_CAPS_pubmethod Peek

Returns the next available character but does not consume it.(Overrides TextReaderPeek.)

System_CAPS_pubmethod Read

Reads the next character from the input stream and advances the character position by one character.(Overrides TextReaderRead.)

System_CAPS_pubmethod Read

Reads a specified maximum of characters from the current stream into a buffer, beginning at the specified index.(Overrides TextReaderRead.)

System_CAPS_pubmethod ReadAsync

Reads a specified maximum number of characters from the current stream asynchronously and writes the data to a buffer, beginning at the specified index. (Overrides TextReaderReadAsync.)

System_CAPS_pubmethod ReadBlock

Reads a specified maximum number of characters from the current stream and writes the data to a buffer, beginning at the specified index.(Overrides TextReaderReadBlock.)

System_CAPS_pubmethod ReadBlockAsync

Reads a specified maximum number of characters from the current stream asynchronously and writes the data to a buffer, beginning at the specified index.(Overrides TextReaderReadBlockAsync.)

System_CAPS_pubmethod ReadLine

Reads a line of characters from the current stream and returns the data as a string.(Overrides TextReaderReadLine.)

System_CAPS_pubmethod ReadLineAsync

Reads a line of characters asynchronously from the current stream and returns the data as a string.(Overrides TextReaderReadLineAsync.)

System_CAPS_pubmethod ReadToEnd

Reads all characters from the current position to the end of the stream.(Overrides TextReaderReadToEnd.)

System_CAPS_pubmethod ReadToEndAsync

Reads all characters from the current position to the end of the stream asynchronously and returns them as one string.(Overrides TextReaderReadToEndAsync.)

System_CAPS_pubmethod ToString

Returns a string that represents the current object.(Inherited from Object.)

NameDescription
System_CAPS_pubfield System_CAPS_static Null

A StreamReader object around an empty stream.

System_CAPS_noteNote

To view the .NET Framework source code for this type, see the Reference Source. You can browse through the source code online, download the reference for offline viewing, and step through the sources (including patches and updates) during debugging; see instructions.

StreamReader is designed for character input in a particular encoding, whereas the Stream class is designed for byte input and output. Use StreamReader for reading lines of information from a standard text file.

System_CAPS_importantImportant

This type implements the IDisposable interface. When you have finished using the type, you should dispose of it either directly or indirectly. To dispose of the type directly, call its Dispose method in a try/catch block. To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). For more information, see the “Using an Object that Implements IDisposable” section in the IDisposable interface topic.

StreamReader defaults to UTF-8 encoding unless specified otherwise, instead of defaulting to the ANSI code page for the current system. UTF-8 handles Unicode characters correctly and provides consistent results on localized versions of the operating system. If you get the current character encoding using the property, the value is not reliable until after the first Read method, since encoding auto detection is not done until the first call to a Read method.

By default, a StreamReader is not thread safe. See TextReaderSynchronized for a thread-safe wrapper.

The Read and Write method overloads read and write the number of characters specified by the count parameter. These are to be distinguished from BufferedStreamRead and BufferedStreamWrite, which read and write the number of bytes specified by the count parameter. Use the BufferedStream methods only for reading and writing an integral number of byte array elements.

System_CAPS_noteNote

When reading from a Stream, it is more efficient to use a buffer that is the same size as the internal buffer of the stream.

For a list of common I/O tasks, see Common I-O Tasks.

The following example uses an instance of StreamReader to read text from a file. The constructor used in this example is not supported for use in Windows Store Apps.

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);
        }
    }
}
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
using namespace System;
using namespace System::IO;
int main()
{
   try
   {
      // Create an instance of StreamReader to read from a file.
      StreamReader^ sr = gcnew StreamReader( "TestFile.txt" );
      try
      {
         String^ line;

         // Read and display lines from the file until the end of 
         // the file is reached.
         while ( line = sr->ReadLine() )
         {
            Console::WriteLine( line );
         }
      }
      finally
      {
         if ( sr )
            delete (IDisposable^)sr;
      }
   }
   catch ( Exception^ e ) 
   {
      // Let the user know what went wrong.
      Console::WriteLine( "The file could not be read:" );
      Console::WriteLine( e->Message );
   }
}

The following example instantiates a StreamReader object and calls its ReadAsync method to read a file asynchronously.

using System;
using System.IO;
using System.Threading.Tasks;

class Example
{
    public static void Main()
    {
        ReadAndDisplayFilesAsync();
    }

    private async static void ReadAndDisplayFilesAsync()
    {
        String filename = "TestFile1.txt";
        Char[] buffer;

        using (var sr = new StreamReader(filename)) {
            buffer = new Char[(int)sr.BaseStream.Length];
            await sr.ReadAsync(buffer, 0, (int)sr.BaseStream.Length);
        }

        Console.WriteLine(new String(buffer));
    }
}
// The example displays the following output:
//       This is the first line of text in a relatively short file.
//       This is the second line.
//       This is the third line.
//       This is the fourth and final line.
Imports System
Imports System.IO
Imports System.Threading.Tasks

Module Example
    Public Sub Main()
        ReadAndDisplayFilesAsync()
    End Sub

    Private Async Sub ReadAndDisplayFilesAsync()
        Dim filename As String = "TestFile1.txt"
        Dim buffer() As Char

        Using sr As New StreamReader(filename)
            ReDim buffer(CInt(sr.BaseStream.Length))
            Await sr.ReadAsync(buffer, 0, CInt(sr.BaseStream.Length))
        End Using

        Console.WriteLine(New String(buffer))
    End Sub
End Module
' The example displays the following output:
'       This is the first line of text in a relatively short file.
'       This is the second line.
'       This is the third line.
'       This is the fourth and final line.
Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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