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Encoding.GetString Method (Byte[], Int32, Int32)

When overridden in a derived class, decodes a sequence of bytes from the specified byte array into a string.

Namespace:  System.Text
Assemblies:   mscorlib (in mscorlib.dll)
  System.Text.Encoding (in System.Text.Encoding.dll)

public virtual string GetString(
	byte[] bytes,
	int index,
	int count


Type: System.Byte[]

The byte array containing the sequence of bytes to decode.

Type: System.Int32

The index of the first byte to decode.

Type: System.Int32

The number of bytes to decode.

Return Value

Type: System.String
A string that contains the results of decoding the specified sequence of bytes.


The byte array contains invalid Unicode code points.


bytes is null.


index or count is less than zero.


index and count do not denote a valid range in bytes.


A fallback occurred (see Character Encoding in the .NET Framework for complete explanation)


DecoderFallback is set to DecoderExceptionFallback.

If the data to be converted is available only in sequential blocks (such as data read from a stream) or if the amount of data is so large that it needs to be divided into smaller blocks, you should use the Decoder or the Encoder provided by the GetDecoder method or the GetEncoder method, respectively, of a derived class.

See the Remarks section of the Encoding.GetChars reference topic for a discussion of decoding techniques and considerations.

The following example reads a UTF-8 encoded string from a binary file that is represented by a FileStream object. For files that are smaller than 2,048 bytes, it reads the contents of the entire file into a byte array and calls the GetString(Byte[], Int32, Int32) method to perform the decoding. For larger files, it reads 2,048 bytes at a time into a byte array, calls the Decoder.GetCharCount(Byte[], Int32, Int32) method to determine how many characters are contained in the array, and then calls the Decoder.GetChars(Byte[], Int32, Int32, Char[], Int32) method to perform the decoding.

using System;
using System.IO;
using System.Text;

public class Example
   const int MAX_BUFFER_SIZE = 2048;
   static Encoding enc8 = Encoding.UTF8;
   static byte[] bytes = new byte[MAX_BUFFER_SIZE]; 

   public static void Main()
      FileStream fStream = new FileStream(@".\Utf8Example.txt", FileMode.Open);
      string contents = null;

      // If file size is small, read in a single operation. 
      if (fStream.Length <= MAX_BUFFER_SIZE) {
         int bytesRead = fStream.Read(bytes, 0, bytes.Length);
         contents = enc8.GetString(bytes, 0, bytesRead);
      // If file size exceeds buffer size, perform multiple reads. 
      else {
         contents = ReadFromBuffer(fStream);

    private static string ReadFromBuffer(FileStream fStream)
        string output = String.Empty;
        Decoder decoder8 = enc8.GetDecoder();

        while (fStream.Position < fStream.Length) {
           int nBytes = fStream.Read(bytes, 0, bytes.Length);
           int nChars = decoder8.GetCharCount(bytes, 0, nBytes);
           char[] chars = new char[nChars];
           nChars = decoder8.GetChars(bytes, 0, nBytes, chars, 0);
           output += new String(chars, 0, nChars);                                                     
        return output;
// The example displays the following output: 
//     This is a UTF-8-encoded file that contains primarily Latin text, although it 
//     does list the first twelve letters of the Russian (Cyrillic) alphabet: 
//     А б в г д е ё ж з и й к 
//     The goal is to save this file, then open and decode it as a binary stream.

The example uses the following text, which should be saved to a UTF-8 encoded file named Utf8Example.txt.

This is a UTF-8-encoded file that contains primarily Latin text, although it 
does list the first twelve letters of the Russian (Cyrillic) alphabet:

А б в г д е ё ж з и й к

The goal is to save this file, then open and decode it as a binary stream.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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