BinaryReader.Read Method (Char[], Int32, Int32)

Reads count characters from the stream with index as the starting point in the character array.

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

virtual int Read (
	array<wchar_t>^ buffer, 
	int index, 
	int count
public int Read (
	char[] buffer, 
	int index, 
	int count
public function Read (
	buffer : char[], 
	index : int, 
	count : int
) : int
Not applicable.



The buffer to read data into.


The starting point in the buffer at which to begin reading into the buffer.


The number of characters to read.

Return Value

The total number of characters read into the buffer. This might be less than the number of characters requested if that many characters are not currently available, or it might be zero if the end of the stream is reached.

Exception typeCondition


The buffer length minus index is less than count.


buffer is a null reference (Nothing in Visual Basic).


index or count is negative.


The stream is closed.


An I/O error occurs.

BinaryReader does not restore the file position after an unsuccessful read.

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

The following example shows how to read and write data using memory as a backing store. This example displays a list of invalid file path characters to the console. Although the code tries to display a list of all invalid file path characters, not all of the characters are within the displayable set of characters. Because the list of invalid characters can vary based on the system, output for this code may also vary.

using namespace System;
using namespace System::IO;
int main()
   array<Char>^invalidPathChars = Path::InvalidPathChars;
   MemoryStream^ memStream = gcnew MemoryStream;
   BinaryWriter^ binWriter = gcnew BinaryWriter( memStream );
   // Write to memory.
   binWriter->Write( "Invalid file path characters are: " );
   binWriter->Write( Path::InvalidPathChars, 0, Path::InvalidPathChars->Length );
   // Create the reader using the same MemoryStream 
   // as used with the writer.
   BinaryReader^ binReader = gcnew BinaryReader( memStream );
   // Set Position to the beginning of the stream.
   binReader->BaseStream->Position = 0;
   // Read the data from memory and write it to the console.
   Console::Write( binReader->ReadString() );
   int arraySize = (int)(memStream->Length - memStream->Position);
   array<Char>^memoryData = gcnew array<Char>(arraySize);
   binReader->Read( memoryData, 0, arraySize );
   Console::WriteLine( memoryData );

import System.*;
import System.IO.*;

class BinaryRW
    public static void main(String[] args)
        char invalidPathChars[] = Path.InvalidPathChars;
        MemoryStream memStream = new MemoryStream();
        BinaryWriter binWriter = new BinaryWriter(memStream);

        // Write to memory.
        binWriter.Write("Invalid file path characters are: ");
        binWriter.Write(Path.InvalidPathChars, 0, Path.InvalidPathChars.length);

        // Create the reader using the same MemoryStream
        // as used with the writer.
        BinaryReader binReader = new BinaryReader(memStream);

        // Set Position to the beginning of the stream.

        // Read the data from memory and write it to the console.
        int arraySize = (int)(memStream.get_Length()-memStream.get_Position());
        char memoryData[] = new char[arraySize];
        binReader.Read(memoryData, 0, arraySize);
    } //main
} //BinaryRW

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0