BinaryWriter.Write Method

Reference

Definition

Namespace:: System.IO

Assembly:: System.IO.dll

Assembly:: System.Runtime.dll

Assembly:: System.Runtime.Extensions.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Writes a value to the current stream.

Overloads

Write(Char[], Int32, Int32)	Writes a section of a character array to the current stream, and advances the current position of the stream in accordance with the `Encoding` used and perhaps the specific characters being written to the stream.
Write(Byte[], Int32, Int32)	Writes a region of a byte array to the current stream.
Write(UInt64)	Writes an eight-byte unsigned integer to the current stream and advances the stream position by eight bytes.
Write(UInt32)	Writes a four-byte unsigned integer to the current stream and advances the stream position by four bytes.
Write(UInt16)	Writes a two-byte unsigned integer to the current stream and advances the stream position by two bytes.
Write(String)	Writes a length-prefixed string to this stream in the current encoding of the BinaryWriter, and advances the current position of the stream in accordance with the encoding used and the specific characters being written to the stream.
Write(Single)	Writes a four-byte floating-point value to the current stream and advances the stream position by four bytes.
Write(SByte)	Writes a signed byte to the current stream and advances the stream position by one byte.
Write(ReadOnlySpan<Char>)	Writes a span of characters to the current stream, and advances the current position of the stream in accordance with the `Encoding` used and perhaps the specific characters being written to the stream.
Write(ReadOnlySpan<Byte>)	Writes a span of bytes to the current stream.
Write(Int64)	Writes an eight-byte signed integer to the current stream and advances the stream position by eight bytes.
Write(Char[])	Writes a character array to the current stream and advances the current position of the stream in accordance with the `Encoding` used and the specific characters being written to the stream.
Write(Int16)	Writes a two-byte signed integer to the current stream and advances the stream position by two bytes.
Write(Half)	Writes a two-byte floating-point value to the current stream and advances the stream position by two bytes.
Write(Double)	Writes an eight-byte floating-point value to the current stream and advances the stream position by eight bytes.
Write(Decimal)	Writes a decimal value to the current stream and advances the stream position by sixteen bytes.
Write(Char)	Writes a Unicode character to the current stream and advances the current position of the stream in accordance with the `Encoding` used and the specific characters being written to the stream.
Write(Byte[])	Writes a byte array to the underlying stream.
Write(Byte)	Writes an unsigned byte to the current stream and advances the stream position by one byte.
Write(Boolean)	Writes a one-byte `Boolean` value to the current stream, with 0 representing `false` and 1 representing `true`.
Write(Int32)	Writes a four-byte signed integer to the current stream and advances the stream position by four bytes.

Write(Char[], Int32, Int32)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a section of a character array to the current stream, and advances the current position of the stream in accordance with the Encoding used and perhaps the specific characters being written to the stream.

public:
 virtual void Write(cli::array <char> ^ chars, int index, int count);

public virtual void Write (char[] chars, int index, int count);

abstract member Write : char[] * int * int -> unit
override this.Write : char[] * int * int -> unit

Public Overridable Sub Write (chars As Char(), index As Integer, count As Integer)

Parameters

chars: Char[]

A character array containing the data to write.

index: Int32

The index of the first character to read from chars and to write to the stream.

count: Int32

The number of characters to read from chars and to write to the stream.

Exceptions

ArgumentException

The buffer length minus index is less than count.

ArgumentNullException

chars is null.

ArgumentOutOfRangeException

index or count is negative.

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Examples

The following code example shows how to read and write data using memory as a backing store.

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 );
}

using System;
using System.IO;

class BinaryRW
{
    static void Main()
    {
        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.
        memStream.Position = 0;

        // Read the data from memory and write it to the console.
        Console.Write(binReader.ReadString());
        int arraySize = (int)(memStream.Length - memStream.Position);
        char[] memoryData = new char[arraySize];
        binReader.Read(memoryData, 0, arraySize);
        Console.WriteLine(memoryData);
    }
}

open System.IO

let invalidPathChars = Path.GetInvalidPathChars()
let memStream = new MemoryStream()
let binWriter = new BinaryWriter(memStream)

// Write to memory.
binWriter.Write "Invalid file path characters are: "
binWriter.Write(invalidPathChars, 0, invalidPathChars.Length)

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

// Set Position to the beginning of the stream.
memStream.Position <- 0

// Read the data from memory and write it to the console.
printf $"{binReader.ReadString()}"
let arraySize = memStream.Length - memStream.Position |> int
let memoryData = Array.zeroCreate<char> arraySize
binReader.Read(memoryData, 0, arraySize) |> ignore
printfn $"{memoryData}"

Imports System.IO

Public Class BinaryRW

    Shared Sub Main()
    
        Dim invalidPathChars() As Char = Path.InvalidPathChars
        Dim memStream As new MemoryStream()
        Dim binWriter As 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.
        Dim binReader As New BinaryReader(memStream)

        ' Set Position to the beginning of the stream.
        memStream.Position = 0

        ' Read the data from memory and write it to the console.
        Console.Write(binReader.ReadString())
        Dim upperBound As Integer = _
            CInt(memStream.Length - memStream.Position) - 1
        Dim memoryData(upperBound) As Char
        binReader.Read(memoryData, 0, upperBound)
        Console.WriteLine(memoryData)
    
    End Sub
End Class

Remarks

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

Applies to

Write(Byte[], Int32, Int32)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a region of a byte array to the current stream.

public:
 virtual void Write(cli::array <System::Byte> ^ buffer, int index, int count);

public virtual void Write (byte[] buffer, int index, int count);

abstract member Write : byte[] * int * int -> unit
override this.Write : byte[] * int * int -> unit

Public Overridable Sub Write (buffer As Byte(), index As Integer, count As Integer)

Parameters

buffer: Byte[]

A byte array containing the data to write.

index: Int32

The index of the first byte to read from buffer and to write to the stream.

count: Int32

The number of bytes to read from buffer and to write to the stream.

Exceptions

ArgumentException

The buffer length minus index is less than count.

ArgumentNullException

buffer is null.

ArgumentOutOfRangeException

index or count is negative.

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Examples

The following code example shows how to write binary data using memory as a backing store, and then verify that the data was written correctly.

using System;
using System.IO;

namespace BinaryRW
{
    class Program
    {
        static void Main(string[] args)
        {
            const int arrayLength = 1000;
            byte[] dataArray = new byte[arrayLength];
            byte[] verifyArray = new byte[arrayLength];

            new Random().NextBytes(dataArray);

            using (BinaryWriter binWriter = new BinaryWriter(new MemoryStream()))
            {
                Console.WriteLine("Writing the data.");
                binWriter.Write(dataArray, 0, arrayLength);

                using (BinaryReader binReader = new BinaryReader(binWriter.BaseStream))
                {
                    binReader.BaseStream.Position = 0;

                    if (binReader.Read(verifyArray, 0, arrayLength) != arrayLength)
                    {
                        Console.WriteLine("Error writing the data.");
                        return;
                    }
                }
            }

            for (int i = 0; i < arrayLength; i++)
            {
                if (verifyArray[i] != dataArray[i])
                {
                    Console.WriteLine("Error writing the data.");
                    return;
                }
            }

            Console.WriteLine("The data was written and verified.");
        }
    }
}

open System
open System.IO

let arrayLength = 1000
let dataArray = Array.zeroCreate<byte> arrayLength
let verifyArray = Array.zeroCreate<byte> arrayLength

Random().NextBytes dataArray

do
    use binWriter = new BinaryWriter(new MemoryStream())
    printfn "Writing the data."
    binWriter.Write(dataArray, 0, arrayLength)

    use binReader = new BinaryReader(binWriter.BaseStream)
    binReader.BaseStream.Position <- 0

    if binReader.Read(verifyArray, 0, arrayLength) <> arrayLength then
        printfn "Error writing the data."
    else
        for i = 0 to arrayLength - 1 do
            if verifyArray[i] <> dataArray[i] then
                printfn "Error writing the data."
            else
                printfn "The data was written and verified."

Imports System.IO

Module Module1

    Sub Main()
        Const upperBound As Integer = 1000
        Dim dataArray(upperBound) As Byte
        Dim verifyArray(upperBound) As Byte

        Dim randomGenerator As New Random
        randomGenerator.NextBytes(dataArray)

        Using binWriter As New BinaryWriter(New MemoryStream())
            Console.WriteLine("Writing the data.")
            binWriter.Write(dataArray, 0, dataArray.Length)

            Using binReader As New BinaryReader(binWriter.BaseStream)
                binReader.BaseStream.Position = 0

                If binReader.Read(verifyArray, 0, dataArray.Length) <> dataArray.Length Then
                    Console.WriteLine("Error writing the data.")
                    Return
                End If
            End Using
        End Using

        For i As Integer = 0 To upperBound
            If verifyArray(i) <> dataArray(i) Then
                Console.WriteLine("Error writing the data.")
                Return
            End If
        Next i

        Console.WriteLine("The data was written and verified.")
    End Sub

End Module

Remarks

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

Applies to

Write(UInt64)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Important

This API is not CLS-compliant.

Writes an eight-byte unsigned integer to the current stream and advances the stream position by eight bytes.

public:
 virtual void Write(System::UInt64 value);

[System.CLSCompliant(false)]
public virtual void Write (ulong value);

[<System.CLSCompliant(false)>]
abstract member Write : uint64 -> unit
override this.Write : uint64 -> unit

Public Overridable Sub Write (value As ULong)

Parameters

value: UInt64

The eight-byte unsigned integer to write.

Attributes: CLSCompliantAttribute

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Remarks

BinaryWriter stores this data type in little endian format.

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

Applies to

Write(UInt32)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Important

This API is not CLS-compliant.

Writes a four-byte unsigned integer to the current stream and advances the stream position by four bytes.

public:
 virtual void Write(System::UInt32 value);

[System.CLSCompliant(false)]
public virtual void Write (uint value);

[<System.CLSCompliant(false)>]
abstract member Write : uint32 -> unit
override this.Write : uint32 -> unit

Public Overridable Sub Write (value As UInteger)

Parameters

value: UInt32

The four-byte unsigned integer to write.

Attributes: CLSCompliantAttribute

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Remarks

BinaryWriter stores this data type in little endian format.

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

Applies to

Write(UInt16)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Important

This API is not CLS-compliant.

Writes a two-byte unsigned integer to the current stream and advances the stream position by two bytes.

public:
 virtual void Write(System::UInt16 value);

[System.CLSCompliant(false)]
public virtual void Write (ushort value);

[<System.CLSCompliant(false)>]
abstract member Write : uint16 -> unit
override this.Write : uint16 -> unit

Public Overridable Sub Write (value As UShort)

Parameters

value: UInt16

The two-byte unsigned integer to write.

Attributes: CLSCompliantAttribute

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Remarks

BinaryWriter stores this data type in little endian format.

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

Applies to

Write(String)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a length-prefixed string to this stream in the current encoding of the BinaryWriter, and advances the current position of the stream in accordance with the encoding used and the specific characters being written to the stream.

public:
 virtual void Write(System::String ^ value);

public virtual void Write (string value);

abstract member Write : string -> unit
override this.Write : string -> unit

Public Overridable Sub Write (value As String)

Parameters

value: String

The value to write.

Exceptions

IOException

An I/O error occurs.

ArgumentNullException

value is null.

ObjectDisposedException

The stream is closed.

Examples

The following code example demonstrates how to store and retrieve application settings in a file.

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

class ConsoleApplication
{
    const string fileName = "AppSettings.dat";

    static void Main()
    {
        WriteDefaultValues();
        DisplayValues();
    }

    public static void WriteDefaultValues()
    {
        using (var stream = File.Open(fileName, FileMode.Create))
        {
            using (var writer = new BinaryWriter(stream, Encoding.UTF8, false))
            {
                writer.Write(1.250F);
                writer.Write(@"c:\Temp");
                writer.Write(10);
                writer.Write(true);
            }
        }
    }

    public static void DisplayValues()
    {
        float aspectRatio;
        string tempDirectory;
        int autoSaveTime;
        bool showStatusBar;

        if (File.Exists(fileName))
        {
            using (var stream = File.Open(fileName, FileMode.Open))
            {
                using (var reader = new BinaryReader(stream, Encoding.UTF8, false))
                {
                    aspectRatio = reader.ReadSingle();
                    tempDirectory = reader.ReadString();
                    autoSaveTime = reader.ReadInt32();
                    showStatusBar = reader.ReadBoolean();
                }
            }

            Console.WriteLine("Aspect ratio set to: " + aspectRatio);
            Console.WriteLine("Temp directory is: " + tempDirectory);
            Console.WriteLine("Auto save time set to: " + autoSaveTime);
            Console.WriteLine("Show status bar: " + showStatusBar);
        }
    }
}

open System.IO
open System.Text

let fileName = "AppSettings.dat"

let writeDefaultValues () =
    use stream = File.Open(fileName, FileMode.Create)
    use writer = new BinaryWriter(stream, Encoding.UTF8, false)
    writer.Write 1.250F
    writer.Write @"c:\Temp"
    writer.Write 10
    writer.Write true

let displayValues () =
    if File.Exists fileName then
        use stream = File.Open(fileName, FileMode.Open)
        use reader = new BinaryReader(stream, Encoding.UTF8, false)
        let aspectRatio = reader.ReadSingle()
        let tempDirectory = reader.ReadString()
        let autoSaveTime = reader.ReadInt32()
        let showStatusBar = reader.ReadBoolean()

        printfn $"Aspect ratio set to: {aspectRatio}"
        printfn $"Temp directory is: {tempDirectory}"
        printfn $"Auto save time set to: {autoSaveTime}"
        printfn $"Show status bar: {showStatusBar}"

writeDefaultValues ()
displayValues ()

Imports System.IO

Module Module1
    Const fileName As String = "AppSettings.dat"

    Sub Main()
        WriteDefaultValues()
        DisplayValues()
    End Sub

    Sub WriteDefaultValues()
        Using writer As BinaryWriter = New BinaryWriter(File.Open(fileName, FileMode.Create))
            writer.Write(1.25F)
            writer.Write("c:\Temp")
            writer.Write(10)
            writer.Write(True)
        End Using
    End Sub

    Sub DisplayValues()
        Dim aspectRatio As Single
        Dim tempDirectory As String
        Dim autoSaveTime As Integer
        Dim showStatusBar As Boolean

        If (File.Exists(fileName)) Then

            Using reader As BinaryReader = New BinaryReader(File.Open(fileName, FileMode.Open))
                aspectRatio = reader.ReadSingle()
                tempDirectory = reader.ReadString()
                autoSaveTime = reader.ReadInt32()
                showStatusBar = reader.ReadBoolean()
            End Using

            Console.WriteLine("Aspect ratio set to: " & aspectRatio)
            Console.WriteLine("Temp directory is: " & tempDirectory)
            Console.WriteLine("Auto save time set to: " & autoSaveTime)
            Console.WriteLine("Show status bar: " & showStatusBar)
        End If
    End Sub

End Module

Remarks

Length-prefixed means that this method first writes the length of the string, in bytes, when encoded with the BinaryWriter instance's current encoding to the stream. This value is written as an unsigned integer. This method then writes that many bytes to the stream.

For example, the string "A" has a length of 1, but when encoded with UTF-16; the length is 2 bytes, so the value written in the prefix is 2, and 3 bytes are written to the stream, including the prefix.

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

Applies to

Write(Single)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a four-byte floating-point value to the current stream and advances the stream position by four bytes.

public:
 virtual void Write(float value);

public virtual void Write (float value);

abstract member Write : single -> unit
override this.Write : single -> unit

Public Overridable Sub Write (value As Single)

Parameters

value: Single

The four-byte floating-point value to write.

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Examples

The following code example demonstrates how to store and retrieve application settings in a file.

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

class ConsoleApplication
{
    const string fileName = "AppSettings.dat";

    static void Main()
    {
        WriteDefaultValues();
        DisplayValues();
    }

    public static void WriteDefaultValues()
    {
        using (var stream = File.Open(fileName, FileMode.Create))
        {
            using (var writer = new BinaryWriter(stream, Encoding.UTF8, false))
            {
                writer.Write(1.250F);
                writer.Write(@"c:\Temp");
                writer.Write(10);
                writer.Write(true);
            }
        }
    }

    public static void DisplayValues()
    {
        float aspectRatio;
        string tempDirectory;
        int autoSaveTime;
        bool showStatusBar;

        if (File.Exists(fileName))
        {
            using (var stream = File.Open(fileName, FileMode.Open))
            {
                using (var reader = new BinaryReader(stream, Encoding.UTF8, false))
                {
                    aspectRatio = reader.ReadSingle();
                    tempDirectory = reader.ReadString();
                    autoSaveTime = reader.ReadInt32();
                    showStatusBar = reader.ReadBoolean();
                }
            }

            Console.WriteLine("Aspect ratio set to: " + aspectRatio);
            Console.WriteLine("Temp directory is: " + tempDirectory);
            Console.WriteLine("Auto save time set to: " + autoSaveTime);
            Console.WriteLine("Show status bar: " + showStatusBar);
        }
    }
}

open System.IO
open System.Text

let fileName = "AppSettings.dat"

let writeDefaultValues () =
    use stream = File.Open(fileName, FileMode.Create)
    use writer = new BinaryWriter(stream, Encoding.UTF8, false)
    writer.Write 1.250F
    writer.Write @"c:\Temp"
    writer.Write 10
    writer.Write true

let displayValues () =
    if File.Exists fileName then
        use stream = File.Open(fileName, FileMode.Open)
        use reader = new BinaryReader(stream, Encoding.UTF8, false)
        let aspectRatio = reader.ReadSingle()
        let tempDirectory = reader.ReadString()
        let autoSaveTime = reader.ReadInt32()
        let showStatusBar = reader.ReadBoolean()

        printfn $"Aspect ratio set to: {aspectRatio}"
        printfn $"Temp directory is: {tempDirectory}"
        printfn $"Auto save time set to: {autoSaveTime}"
        printfn $"Show status bar: {showStatusBar}"

writeDefaultValues ()
displayValues ()

Imports System.IO

Module Module1
    Const fileName As String = "AppSettings.dat"

    Sub Main()
        WriteDefaultValues()
        DisplayValues()
    End Sub

    Sub WriteDefaultValues()
        Using writer As BinaryWriter = New BinaryWriter(File.Open(fileName, FileMode.Create))
            writer.Write(1.25F)
            writer.Write("c:\Temp")
            writer.Write(10)
            writer.Write(True)
        End Using
    End Sub

    Sub DisplayValues()
        Dim aspectRatio As Single
        Dim tempDirectory As String
        Dim autoSaveTime As Integer
        Dim showStatusBar As Boolean

        If (File.Exists(fileName)) Then

            Using reader As BinaryReader = New BinaryReader(File.Open(fileName, FileMode.Open))
                aspectRatio = reader.ReadSingle()
                tempDirectory = reader.ReadString()
                autoSaveTime = reader.ReadInt32()
                showStatusBar = reader.ReadBoolean()
            End Using

            Console.WriteLine("Aspect ratio set to: " & aspectRatio)
            Console.WriteLine("Temp directory is: " & tempDirectory)
            Console.WriteLine("Auto save time set to: " & autoSaveTime)
            Console.WriteLine("Show status bar: " & showStatusBar)
        End If
    End Sub

End Module

Remarks

BinaryWriter stores this data type in little endian format.

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

Applies to

Write(SByte)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Important

This API is not CLS-compliant.

Writes a signed byte to the current stream and advances the stream position by one byte.

public:
 virtual void Write(System::SByte value);

[System.CLSCompliant(false)]
public virtual void Write (sbyte value);

[<System.CLSCompliant(false)>]
abstract member Write : sbyte -> unit
override this.Write : sbyte -> unit

Public Overridable Sub Write (value As SByte)

Parameters

value: SByte

The signed byte to write.

Attributes: CLSCompliantAttribute

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Remarks

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

Applies to

Write(ReadOnlySpan<Char>)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a span of characters to the current stream, and advances the current position of the stream in accordance with the Encoding used and perhaps the specific characters being written to the stream.

public:
 virtual void Write(ReadOnlySpan<char> chars);

public virtual void Write (ReadOnlySpan<char> chars);

abstract member Write : ReadOnlySpan<char> -> unit
override this.Write : ReadOnlySpan<char> -> unit

Public Overridable Sub Write (chars As ReadOnlySpan(Of Char))

Parameters

chars: ReadOnlySpan<Char>

A span of chars to write.

Applies to

Write(ReadOnlySpan<Byte>)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a span of bytes to the current stream.

public:
 virtual void Write(ReadOnlySpan<System::Byte> buffer);

public virtual void Write (ReadOnlySpan<byte> buffer);

abstract member Write : ReadOnlySpan<byte> -> unit
override this.Write : ReadOnlySpan<byte> -> unit

Public Overridable Sub Write (buffer As ReadOnlySpan(Of Byte))

Parameters

buffer: ReadOnlySpan<Byte>

The span of bytes to write.

Applies to

Write(Int64)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes an eight-byte signed integer to the current stream and advances the stream position by eight bytes.

public:
 virtual void Write(long value);

public virtual void Write (long value);

abstract member Write : int64 -> unit
override this.Write : int64 -> unit

Public Overridable Sub Write (value As Long)

Parameters

value: Int64

The eight-byte signed integer to write.

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Remarks

BinaryWriter stores this data type in little endian format.

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

Applies to

Write(Char[])

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a character array to the current stream and advances the current position of the stream in accordance with the Encoding used and the specific characters being written to the stream.

public:
 virtual void Write(cli::array <char> ^ chars);

public virtual void Write (char[] chars);

abstract member Write : char[] -> unit
override this.Write : char[] -> unit

Public Overridable Sub Write (chars As Char())

Parameters

chars: Char[]

A character array containing the data to write.

Exceptions

ArgumentNullException

chars is null.

ObjectDisposedException

The stream is closed.

IOException

An I/O error occurs.

Examples

The following code example shows how to read and write data using memory as a backing store.

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 );
   
   // 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() );
   Console::WriteLine( binReader->ReadChars( (int)(memStream->Length - memStream->Position) ) );
}

using System;
using System.IO;

class BinaryRW
{
    static void Main()
    {
        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);

        // 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.
        memStream.Position = 0;

        // Read the data from memory and write it to the console.
        Console.Write(binReader.ReadString());
        Console.WriteLine(binReader.ReadChars(
            (int)(memStream.Length - memStream.Position)));
    }
}

open System.IO

let invalidPathChars = Path.GetInvalidPathChars()
let memStream = new MemoryStream()
let binWriter = new BinaryWriter(memStream)

// Write to memory.
binWriter.Write "Invalid file path characters are: "
binWriter.Write invalidPathChars

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

// Set Position to the beginning of the stream.
memStream.Position <- 0

// Read the data from memory and write it to the console.
printf $"{binReader.ReadString()}"
printfn $"{binReader.ReadChars(int (memStream.Length - memStream.Position))}"

Imports System.IO

Public Class BinaryRW

    Shared Sub Main()
    
        Dim invalidPathChars() As Char = Path.InvalidPathChars
        Dim memStream As new MemoryStream()
        Dim binWriter As New BinaryWriter(memStream)

        ' Write to memory.
        binWriter.Write("Invalid file path characters are: ")
        binWriter.Write(Path.InvalidPathChars)

        ' Create the reader using the same MemoryStream 
        ' as used with the writer.
        Dim binReader As New BinaryReader(memStream)

        ' Set Position to the beginning of the stream.
        memStream.Position = 0

        ' Read the data from memory and write it to the console.
        Console.Write(binReader.ReadString())
        Console.WriteLine(binReader.ReadChars( _
            CInt(memStream.Length - memStream.Position)))
    
    End Sub
End Class

Remarks

The following table lists examples of other typical or related I/O tasks.

To do this...	See the example in this topic...
Create a text file.	How to: Write Text to a File
Write to a text file.	How to: Write Text to a File
Read from a text file.	How to: Read Text from a File
Append text to a file.	How to: Open and Append to a Log File File.AppendText FileInfo.AppendText
Get the size of a file.	FileInfo.Length
Get the attributes of a file.	File.GetAttributes
Set the attributes of a file.	File.SetAttributes
Determine if a file exists.	File.Exists
Read from a binary file.	How to: Read and Write to a Newly Created Data File
Write to a binary file.	How to: Read and Write to a Newly Created Data File

Applies to

Write(Int16)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a two-byte signed integer to the current stream and advances the stream position by two bytes.

public:
 virtual void Write(short value);

public virtual void Write (short value);

abstract member Write : int16 -> unit
override this.Write : int16 -> unit

Public Overridable Sub Write (value As Short)

Parameters

value: Int16

The two-byte signed integer to write.

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Remarks

BinaryWriter stores this data type in little endian format.

The following table lists examples of other typical or related I/O tasks.

To do this...	See the example in this topic...
Create a text file.	How to: Write Text to a File
Write to a text file.	How to: Write Text to a File
Read from a text file.	How to: Read Text from a File
Append text to a file.	How to: Open and Append to a Log File File.AppendText FileInfo.AppendText
Get the size of a file.	FileInfo.Length
Get the attributes of a file.	File.GetAttributes
Set the attributes of a file.	File.SetAttributes
Determine if a file exists.	File.Exists
Read from a binary file.	How to: Read and Write to a Newly Created Data File
Write to a binary file.	How to: Read and Write to a Newly Created Data File

Applies to

Write(Half)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a two-byte floating-point value to the current stream and advances the stream position by two bytes.

public:
 virtual void Write(Half value);

public virtual void Write (Half value);

abstract member Write : Half -> unit
override this.Write : Half -> unit

Public Overridable Sub Write (value As Half)

Parameters

value: Half

The two-byte floating-point value to write.

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Examples

The following code example shows how to read and write Double data to memory by using the BinaryReader and BinaryWriter classes on top of the MemoryStream class. MemoryStream only reads and writes Byte data.

using namespace System;
using namespace System::IO;
int main()
{
   int i;
   const int arrayLength = 1000;
   
   // Create random data to write to the stream.
   array<double>^dataArray = gcnew array<double>(arrayLength);
   Random^ randomGenerator = gcnew Random;
   for ( i = 0; i < arrayLength; i++ )
   {
      dataArray[ i ] = 100.1 * randomGenerator->NextDouble();

   }
   BinaryWriter^ binWriter = gcnew BinaryWriter( gcnew MemoryStream );
   try
   {
      
      // Write data to the stream.
      Console::WriteLine( "Writing data to the stream." );
      i = 0;
      for ( i = 0; i < arrayLength; i++ )
      {
         binWriter->Write( dataArray[ i ] );

      }
      
      // Create a reader using the stream from the writer.
      BinaryReader^ binReader = gcnew BinaryReader( binWriter->BaseStream );
      
      // Return to the beginning of the stream.
      binReader->BaseStream->Position = 0;
      try
      {
         
         // Read and verify the data.
         i = 0;
         Console::WriteLine( "Verifying the written data." );
         for ( i = 0; i < arrayLength; i++ )
         {
            if ( binReader->ReadDouble() != dataArray[ i ] )
            {
               Console::WriteLine( "Error writing data." );
               break;
            }

         }
         Console::WriteLine( "The data was written and verified." );
      }
      catch ( EndOfStreamException^ e ) 
      {
         Console::WriteLine( "Error writing data: {0}.", e->GetType()->Name );
      }

   }
   finally
   {
      binWriter->Close();
   }

}

using System;
using System.IO;

class BinaryRW
{
    static void Main()
    {
        int i;
        const int arrayLength = 1000;

        // Create random data to write to the stream.
        Random randomGenerator = new Random();
        double[] dataArray = new double[arrayLength];
        for(i = 0; i < arrayLength; i++)
        {
            dataArray[i] = 100.1 * randomGenerator.NextDouble();
        }

        using(BinaryWriter binWriter =
            new BinaryWriter(new MemoryStream()))
        {
            // Write the data to the stream.
            Console.WriteLine("Writing data to the stream.");
            for(i = 0; i < arrayLength; i++)
            {
                binWriter.Write(dataArray[i]);
            }

            // Create a reader using the stream from the writer.
            using(BinaryReader binReader =
                new BinaryReader(binWriter.BaseStream))
            {
                try
                {
                    // Return to the beginning of the stream.
                    binReader.BaseStream.Position = 0;

                    // Read and verify the data.
                    Console.WriteLine("Verifying the written data.");
                    for(i = 0; i < arrayLength; i++)
                    {
                        if(binReader.ReadDouble() != dataArray[i])
                        {
                            Console.WriteLine("Error writing data.");
                            break;
                        }
                    }
                    Console.WriteLine("The data was written " +
                        "and verified.");
                }
                catch(EndOfStreamException e)
                {
                    Console.WriteLine("Error writing data: {0}.",
                        e.GetType().Name);
                }
            }
        }
    }
}

open System
open System.IO

let arrayLength = 1000

// Create random data to write to the stream.
let randomGenerator = Random()
let dataArray = 
    Array.init arrayLength (fun _ -> 100.1 * randomGenerator.NextDouble())
do
    use binWriter = new BinaryWriter(new MemoryStream())
    // Write the data to the stream.
    printfn $"Writing data to the stream."
    for num in dataArray do
        binWriter.Write num

    // Create a reader using the stream from the writer.
    use binReader = new BinaryReader(binWriter.BaseStream)
    try
        // Return to the beginning of the stream.
        binReader.BaseStream.Position <- 0

        // Read and verify the data.
        printfn "Verifying the written data."
        for num in dataArray do
            if binReader.ReadDouble() <> num then
                printfn "Error writing data."
        printfn "The data was written and verified."
    with :? EndOfStreamException as e ->
        printfn $"Error writing data: {e.GetType().Name}."

Imports System.IO

Public Class BinaryRW

    Shared Sub Main()
    
        Dim i As Integer
        Const upperBound As Integer = 1000

        ' Create random data to write to the stream.
        Dim dataArray(upperBound) As Double
        Dim randomGenerator As New Random()
        For i = 0 To upperBound
            dataArray(i) = 100.1 * randomGenerator.NextDouble()
        Next i

        Dim binWriter As New BinaryWriter(New MemoryStream())
        Try

            ' Write data to the stream.
            Console.WriteLine("Writing data to the stream.")
            
            For i = 0 To upperBound
                binWriter.Write(dataArray(i))
            Next i

            ' Create a reader using the stream from the writer.
            Dim binReader As New BinaryReader(binWriter.BaseStream)

            ' Return to the beginning of the stream.
            binReader.BaseStream.Position = 0

            ' Read and verify the data.
            Try
                Console.WriteLine("Verifying the written data.")
                For i = 0 To upperBound
                    If binReader.ReadDouble() <> dataArray(i) Then
                        Console.WriteLine("Error writing data.")
                        Exit For
                    End If
                Next i
                Console.WriteLine("The data was written and verified.")
            Catch ex As EndOfStreamException
                Console.WriteLine("Error writing data: {0}.", _
                    ex.GetType().Name)
            End Try
        Finally
            binWriter.Close()
        End Try

    End Sub
End Class

Remarks

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

Applies to

Write(Double)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes an eight-byte floating-point value to the current stream and advances the stream position by eight bytes.

public:
 virtual void Write(double value);

public virtual void Write (double value);

abstract member Write : double -> unit
override this.Write : double -> unit

Public Overridable Sub Write (value As Double)

Parameters

value: Double

The eight-byte floating-point value to write.

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Examples

using namespace System;
using namespace System::IO;
int main()
{
   int i;
   const int arrayLength = 1000;
   
   // Create random data to write to the stream.
   array<double>^dataArray = gcnew array<double>(arrayLength);
   Random^ randomGenerator = gcnew Random;
   for ( i = 0; i < arrayLength; i++ )
   {
      dataArray[ i ] = 100.1 * randomGenerator->NextDouble();

   }
   BinaryWriter^ binWriter = gcnew BinaryWriter( gcnew MemoryStream );
   try
   {
      
      // Write data to the stream.
      Console::WriteLine( "Writing data to the stream." );
      i = 0;
      for ( i = 0; i < arrayLength; i++ )
      {
         binWriter->Write( dataArray[ i ] );

      }
      
      // Create a reader using the stream from the writer.
      BinaryReader^ binReader = gcnew BinaryReader( binWriter->BaseStream );
      
      // Return to the beginning of the stream.
      binReader->BaseStream->Position = 0;
      try
      {
         
         // Read and verify the data.
         i = 0;
         Console::WriteLine( "Verifying the written data." );
         for ( i = 0; i < arrayLength; i++ )
         {
            if ( binReader->ReadDouble() != dataArray[ i ] )
            {
               Console::WriteLine( "Error writing data." );
               break;
            }

         }
         Console::WriteLine( "The data was written and verified." );
      }
      catch ( EndOfStreamException^ e ) 
      {
         Console::WriteLine( "Error writing data: {0}.", e->GetType()->Name );
      }

   }
   finally
   {
      binWriter->Close();
   }

}

using System;
using System.IO;

class BinaryRW
{
    static void Main()
    {
        int i;
        const int arrayLength = 1000;

        // Create random data to write to the stream.
        Random randomGenerator = new Random();
        double[] dataArray = new double[arrayLength];
        for(i = 0; i < arrayLength; i++)
        {
            dataArray[i] = 100.1 * randomGenerator.NextDouble();
        }

        using(BinaryWriter binWriter =
            new BinaryWriter(new MemoryStream()))
        {
            // Write the data to the stream.
            Console.WriteLine("Writing data to the stream.");
            for(i = 0; i < arrayLength; i++)
            {
                binWriter.Write(dataArray[i]);
            }

            // Create a reader using the stream from the writer.
            using(BinaryReader binReader =
                new BinaryReader(binWriter.BaseStream))
            {
                try
                {
                    // Return to the beginning of the stream.
                    binReader.BaseStream.Position = 0;

                    // Read and verify the data.
                    Console.WriteLine("Verifying the written data.");
                    for(i = 0; i < arrayLength; i++)
                    {
                        if(binReader.ReadDouble() != dataArray[i])
                        {
                            Console.WriteLine("Error writing data.");
                            break;
                        }
                    }
                    Console.WriteLine("The data was written " +
                        "and verified.");
                }
                catch(EndOfStreamException e)
                {
                    Console.WriteLine("Error writing data: {0}.",
                        e.GetType().Name);
                }
            }
        }
    }
}

open System
open System.IO

let arrayLength = 1000

// Create random data to write to the stream.
let randomGenerator = Random()
let dataArray = 
    Array.init arrayLength (fun _ -> 100.1 * randomGenerator.NextDouble())
do
    use binWriter = new BinaryWriter(new MemoryStream())
    // Write the data to the stream.
    printfn $"Writing data to the stream."
    for num in dataArray do
        binWriter.Write num

    // Create a reader using the stream from the writer.
    use binReader = new BinaryReader(binWriter.BaseStream)
    try
        // Return to the beginning of the stream.
        binReader.BaseStream.Position <- 0

        // Read and verify the data.
        printfn "Verifying the written data."
        for num in dataArray do
            if binReader.ReadDouble() <> num then
                printfn "Error writing data."
        printfn "The data was written and verified."
    with :? EndOfStreamException as e ->
        printfn $"Error writing data: {e.GetType().Name}."

Imports System.IO

Public Class BinaryRW

    Shared Sub Main()
    
        Dim i As Integer
        Const upperBound As Integer = 1000

        ' Create random data to write to the stream.
        Dim dataArray(upperBound) As Double
        Dim randomGenerator As New Random()
        For i = 0 To upperBound
            dataArray(i) = 100.1 * randomGenerator.NextDouble()
        Next i

        Dim binWriter As New BinaryWriter(New MemoryStream())
        Try

            ' Write data to the stream.
            Console.WriteLine("Writing data to the stream.")
            
            For i = 0 To upperBound
                binWriter.Write(dataArray(i))
            Next i

            ' Create a reader using the stream from the writer.
            Dim binReader As New BinaryReader(binWriter.BaseStream)

            ' Return to the beginning of the stream.
            binReader.BaseStream.Position = 0

            ' Read and verify the data.
            Try
                Console.WriteLine("Verifying the written data.")
                For i = 0 To upperBound
                    If binReader.ReadDouble() <> dataArray(i) Then
                        Console.WriteLine("Error writing data.")
                        Exit For
                    End If
                Next i
                Console.WriteLine("The data was written and verified.")
            Catch ex As EndOfStreamException
                Console.WriteLine("Error writing data: {0}.", _
                    ex.GetType().Name)
            End Try
        Finally
            binWriter.Close()
        End Try

    End Sub
End Class

Remarks

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

Applies to

Write(Decimal)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a decimal value to the current stream and advances the stream position by sixteen bytes.

public:
 virtual void Write(System::Decimal value);

public virtual void Write (decimal value);

abstract member Write : decimal -> unit
override this.Write : decimal -> unit

Public Overridable Sub Write (value As Decimal)

Parameters

value: Decimal

The decimal value to write.

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Remarks

The following table lists examples of other typical or related I/O tasks.

To do this...	See the example in this topic...
Create a text file.	How to: Write Text to a File
Write to a text file.	How to: Write Text to a File
Read from a text file.	How to: Read Text from a File
Append text to a file.	How to: Open and Append to a Log File File.AppendText FileInfo.AppendText
Get the size of a file.	FileInfo.Length
Get the attributes of a file.	File.GetAttributes
Set the attributes of a file.	File.SetAttributes
Determine if a file exists.	File.Exists
Read from a binary file.	How to: Read and Write to a Newly Created Data File
Write to a binary file.	How to: Read and Write to a Newly Created Data File

Applies to

Write(Char)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a Unicode character to the current stream and advances the current position of the stream in accordance with the Encoding used and the specific characters being written to the stream.

public:
 virtual void Write(char ch);

public virtual void Write (char ch);

abstract member Write : char -> unit
override this.Write : char -> unit

Public Overridable Sub Write (ch As Char)

Parameters

ch: Char

The non-surrogate, Unicode character to write.

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

ArgumentException

ch is a single surrogate character.

Examples

The following code example shows how to read and write data using memory as a backing store.

using namespace System;
using namespace System::IO;
int main()
{
   int i;
   array<Char>^invalidPathChars = Path::InvalidPathChars;
   MemoryStream^ memStream = gcnew MemoryStream;
   BinaryWriter^ binWriter = gcnew BinaryWriter( memStream );
   
   // Write to memory.
   binWriter->Write( "Invalid file path characters are: " );
   for ( i = 0; i < invalidPathChars->Length; i++ )
   {
      binWriter->Write( invalidPathChars[ i ] );

   }
   
   // 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() );
   array<Char>^memoryData = gcnew array<Char>(memStream->Length - memStream->Position);
   for ( i = 0; i < memoryData->Length; i++ )
   {
      memoryData[ i ] = binReader->ReadChar();

   }
   Console::WriteLine( memoryData );
}

using System;
using System.IO;

class BinaryRW
{
    static void Main()
    {
        int i = 0;
        char[] invalidPathChars = Path.InvalidPathChars;
        MemoryStream memStream = new MemoryStream();
        BinaryWriter binWriter = new BinaryWriter(memStream);

        // Write to memory.
        binWriter.Write("Invalid file path characters are: ");
        for(i = 0; i < invalidPathChars.Length; i++)
        {
            binWriter.Write(invalidPathChars[i]);
        }

        // 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.
        memStream.Position = 0;

        // Read the data from memory and write it to the console.
        Console.Write(binReader.ReadString());
        char[] memoryData =
            new char[memStream.Length - memStream.Position];
        for(i = 0; i < memoryData.Length; i++)
        {
            memoryData[i] = binReader.ReadChar();
        }
        Console.WriteLine(memoryData);
    }
}

open System.IO

let invalidPathChars = Path.GetInvalidPathChars()
let memStream = new MemoryStream()
let binWriter = new BinaryWriter(memStream)

// Write to memory.
binWriter.Write "Invalid file path characters are: "
for i = 0 to invalidPathChars.Length - 1 do
    binWriter.Write invalidPathChars[i]

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

// Set Position to the beginning of the stream.
memStream.Position <- 0

// Read the data from memory and write it to the console.
printf $"{binReader.ReadString()}"
let memoryData = Array.zeroCreate<char> (int (memStream.Length - memStream.Position))
for i = 0 to memoryData.Length - 1 do
    memoryData[i] <- binReader.ReadChar()
printfn $"{memoryData}"

Imports System.IO

Public Class BinaryRW

    Shared Sub Main()
    
        Dim i As Integer = 0
        Dim invalidPathChars() As Char = Path.InvalidPathChars
        Dim memStream As new MemoryStream()
        Dim binWriter As New BinaryWriter(memStream)

        ' Write to memory.
        binWriter.Write("Invalid file path characters are: ")
        For i = 0 To invalidPathChars.Length - 1
            binWriter.Write(invalidPathChars(i))
        Next i

        ' Create the reader using the same MemoryStream 
        ' as used with the writer.
        Dim binReader As New BinaryReader(memStream)

        ' Set Position to the beginning of the stream.
        memStream.Position = 0

        ' Read the data from memory and write it to the console.
        Console.Write(binReader.ReadString())
        Dim memoryData( _
            CInt(memStream.Length - memStream.Position) - 1) As Char
        For i = 0 To memoryData.Length - 1
            memoryData(i) = binReader.ReadChar()
        Next i
        Console.WriteLine(memoryData)
    
    End Sub
End Class

Remarks

Because of data formatting conflicts, using this method with the following encodings is not recommended:

UTF-7
ISO-2022-JP
ISCII

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

Unicode surrogate characters must be written out as pairs together in the same call, not individually. If you require support for surrogate pairs in your application, consider using a character array and the Write method overload.

Applies to

Write(Byte[])

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a byte array to the underlying stream.

public:
 virtual void Write(cli::array <System::Byte> ^ buffer);

public virtual void Write (byte[] buffer);

abstract member Write : byte[] -> unit
override this.Write : byte[] -> unit

Public Overridable Sub Write (buffer As Byte())

Parameters

buffer: Byte[]

A byte array containing the data to write.

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

ArgumentNullException

buffer is null.

Examples

The following code example shows how to write binary data using memory as a backing store, and then verify that the data was written correctly.

using namespace System;
using namespace System::IO;
int main()
{
   const int arrayLength = 1000;
   
   // Create random data to write to the stream.
   array<Byte>^dataArray = gcnew array<Byte>(arrayLength);
   (gcnew Random)->NextBytes( dataArray );
   BinaryWriter^ binWriter = gcnew BinaryWriter( gcnew MemoryStream );
   
   // Write the data to the stream.
   Console::WriteLine(  "Writing the data." );
   binWriter->Write( dataArray );
   
   // Create the reader using the stream from the writer.
   BinaryReader^ binReader = gcnew BinaryReader( binWriter->BaseStream );
   
   // Set the stream position to the beginning of the stream.
   binReader->BaseStream->Position = 0;
   
   // Read and verify the data.
   array<Byte>^verifyArray = binReader->ReadBytes( arrayLength );
   if ( verifyArray->Length != arrayLength )
   {
      Console::WriteLine( "Error writing the data." );
      return  -1;
   }

   for ( int i = 0; i < arrayLength; i++ )
   {
      if ( verifyArray[ i ] != dataArray[ i ] )
      {
         Console::WriteLine( "Error writing the data." );
         return  -1;
      }

   }
   Console::WriteLine( "The data was written and verified." );
}

using System;
using System.IO;

class BinaryRW
{
    static void Main()
    {
        const int arrayLength = 1000;

        // Create random data to write to the stream.
        byte[] dataArray = new byte[arrayLength];
        new Random().NextBytes(dataArray);

        BinaryWriter binWriter = new BinaryWriter(new MemoryStream());

        // Write the data to the stream.
        Console.WriteLine("Writing the data.");
        binWriter.Write(dataArray);

        // Create the reader using the stream from the writer.
        BinaryReader binReader =
            new BinaryReader(binWriter.BaseStream);

        // Set Position to the beginning of the stream.
        binReader.BaseStream.Position = 0;

        // Read and verify the data.
        byte[] verifyArray = binReader.ReadBytes(arrayLength);
        if(verifyArray.Length != arrayLength)
        {
            Console.WriteLine("Error writing the data.");
            return;
        }
        for(int i = 0; i < arrayLength; i++)
        {
            if(verifyArray[i] != dataArray[i])
            {
                Console.WriteLine("Error writing the data.");
                return;
            }
        }
        Console.WriteLine("The data was written and verified.");
    }
}

open System
open System.IO

let arrayLength = 1000

// Create random data to write to the stream.
let dataArray = Array.zeroCreate<byte> arrayLength
Random().NextBytes dataArray

let binWriter = new BinaryWriter(new MemoryStream())

// Write the data to the stream.ch
printfn "Writing the data."
binWriter.Write dataArray

// Create the reader using the stream from the writer.
let binReader = new BinaryReader(binWriter.BaseStream)

// Set Position to the beginning of the stream.
binReader.BaseStream.Position <- 0

// Read and verify the data.
let verifyArray = binReader.ReadBytes arrayLength
if verifyArray.Length <> arrayLength then
    printfn "Error writing the data."
else
    let mutable failed = false
    for i = 0 to arrayLength - 1 do
        if verifyArray[i] <> dataArray[i] then
            printfn "Error writing the data."
            failed <- true
    if not failed then
        printfn "The data was written and verified."

Imports System.IO

Public Class BinaryRW

    Shared Sub Main()
    
        Const upperBound As Integer = 1000

        ' Create random data to write to the stream.
        Dim dataArray(upperBound) As Byte
        Dim randomGenerator As New Random
        randomGenerator.NextBytes(dataArray)

        Dim binWriter As New BinaryWriter(New MemoryStream())

        ' Write the data to the stream.
        Console.WriteLine("Writing the data.")
        binWriter.Write(dataArray)

        ' Create the reader using the stream from the writer.
        Dim binReader As New BinaryReader(binWriter.BaseStream)

        ' Set the stream position to the beginning of the stream.
        binReader.BaseStream.Position = 0

        ' Read and verify the data.
        Dim verifyArray() As Byte = _
            binReader.ReadBytes(dataArray.Length)
        If verifyArray.Length <> dataArray.Length Then
            Console.WriteLine("Error writing the data.")
            Return
        End If
        For i As Integer = 0 To upperBound
            If verifyArray(i) <> dataArray(i) Then
                Console.WriteLine("Error writing the data.")
                Return
            End If
        Next i
        Console.WriteLine("The data was written and verified.")
    
    End Sub
End Class

Remarks

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

Applies to

Write(Byte)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes an unsigned byte to the current stream and advances the stream position by one byte.

public:
 virtual void Write(System::Byte value);

public virtual void Write (byte value);

abstract member Write : byte -> unit
override this.Write : byte -> unit

Public Overridable Sub Write (value As Byte)

Parameters

value: Byte

The unsigned byte to write.

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Examples

The following code example shows how to write binary data using memory as a backing store, and then verify that the data was written correctly.

using namespace System;
using namespace System::IO;
int main()
{
   int i = 0;
   
   // Create random data to write to the stream.
   array<Byte>^writeArray = gcnew array<Byte>(1000);
   (gcnew Random)->NextBytes( writeArray );
   BinaryWriter^ binWriter = gcnew BinaryWriter( gcnew MemoryStream );
   BinaryReader^ binReader = gcnew BinaryReader( binWriter->BaseStream );
   try
   {
      
      // Write the data to the stream.
      Console::WriteLine( "Writing the data." );
      for ( i = 0; i < writeArray->Length; i++ )
      {
         binWriter->Write( writeArray[ i ] );

      }
      
      // Set the stream position to the beginning of the stream.
      binReader->BaseStream->Position = 0;
      
      // Read and verify the data from the stream.
      for ( i = 0; i < writeArray->Length; i++ )
      {
         if ( binReader->ReadByte() != writeArray[ i ] )
         {
            Console::WriteLine( "Error writing the data." );
            return  -1;
         }

      }
      Console::WriteLine( "The data was written and verified." );
   }
   // Catch the EndOfStreamException and write an error message.
   catch ( EndOfStreamException^ e ) 
   {
      Console::WriteLine( "Error writing the data.\n{0}", e->GetType()->Name );
   }

}

using System;
using System.IO;

class BinaryRW
{
    static void Main()
    {
        int i = 0;

        // Create random data to write to the stream.
        byte[] writeArray = new byte[1000];
        new Random().NextBytes(writeArray);

        BinaryWriter binWriter = new BinaryWriter(new MemoryStream());
        BinaryReader binReader =
            new BinaryReader(binWriter.BaseStream);

        try
        {
            // Write the data to the stream.
            Console.WriteLine("Writing the data.");
            for(i = 0; i < writeArray.Length; i++)
            {
                binWriter.Write(writeArray[i]);
            }

            // Set the stream position to the beginning of the stream.
            binReader.BaseStream.Position = 0;

            // Read and verify the data from the stream.
            for(i = 0; i < writeArray.Length; i++)
            {
                if(binReader.ReadByte() != writeArray[i])
                {
                    Console.WriteLine("Error writing the data.");
                    return;
                }
            }
            Console.WriteLine("The data was written and verified.");
        }

        // Catch the EndOfStreamException and write an error message.
        catch(EndOfStreamException e)
        {
            Console.WriteLine("Error writing the data.\n{0}",
                e.GetType().Name);
        }
    }
}

open System
open System.IO

// Create random data to write to the stream.
let writeArray = Array.zeroCreate<byte> 1000
Random().NextBytes writeArray

let binWriter = new BinaryWriter(new MemoryStream())
let binReader = new BinaryReader(binWriter.BaseStream)

try
    // Write the data to the stream.
    printfn "Writing the data."
    for i = 0 to writeArray.Length - 1 do
        binWriter.Write writeArray[i]

    // Set the stream position to the beginning of the stream.
    binReader.BaseStream.Position <- 0

    let mutable failed = false
    // Read and verify the data from the stream.
    for i = 0 to writeArray.Length - 1 do
        if binReader.ReadByte() <> writeArray[i] then
            printfn "Error writing the data."
            failed <- true
    if not failed then
        printfn "The data was written and verified."

// Catch the EndOfStreamException and write an error message.
with :? EndOfStreamException as e ->
    printfn $"Error writing the data.\n{e.GetType().Name}"

Imports System.IO

Public Class BinaryRW

    Shared Sub Main()
    
        Dim i As Integer = 0

        ' Create random data to write to the stream.
        Dim writeArray(1000) As Byte
        Dim randomGenerator As New Random()
        randomGenerator.NextBytes(writeArray)

        Dim binWriter As New BinaryWriter(New MemoryStream())
        Dim binReader As New BinaryReader(binWriter.BaseStream)

        Try
        
            ' Write the data to the stream.
            Console.WriteLine("Writing the data.")
            For i = 0 To writeArray.Length - 1
                binWriter.Write(writeArray(i))
            Next i

            ' Set the stream position to the beginning of the stream.
            binReader.BaseStream.Position = 0

            ' Read and verify the data from the stream.
            For i = 0 To writeArray.Length - 1
                If binReader.ReadByte() <> writeArray(i) Then
                    Console.WriteLine("Error writing the data.")
                    Return
                End If
            Next i
            Console.WriteLine("The data was written and verified.")

        ' Catch the EndOfStreamException and write an error message.
        Catch ex As EndOfStreamException
            Console.WriteLine("Error writing the data: {0}", _
                ex.GetType().Name)
        End Try
    
    End Sub
End Class

Remarks

Because of data formatting conflicts, using this method with the following encodings is not recommended:

UTF-7
ISO-2022-JP
ISCII

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

Applies to

Write(Boolean)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a one-byte Boolean value to the current stream, with 0 representing false and 1 representing true.

public:
 virtual void Write(bool value);

public virtual void Write (bool value);

abstract member Write : bool -> unit
override this.Write : bool -> unit

Public Overridable Sub Write (value As Boolean)

Parameters

value: Boolean

The Boolean value to write (0 or 1).

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Examples

The following code example demonstrates how to store and retrieve application settings in a file.

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

class ConsoleApplication
{
    const string fileName = "AppSettings.dat";

    static void Main()
    {
        WriteDefaultValues();
        DisplayValues();
    }

    public static void WriteDefaultValues()
    {
        using (var stream = File.Open(fileName, FileMode.Create))
        {
            using (var writer = new BinaryWriter(stream, Encoding.UTF8, false))
            {
                writer.Write(1.250F);
                writer.Write(@"c:\Temp");
                writer.Write(10);
                writer.Write(true);
            }
        }
    }

    public static void DisplayValues()
    {
        float aspectRatio;
        string tempDirectory;
        int autoSaveTime;
        bool showStatusBar;

        if (File.Exists(fileName))
        {
            using (var stream = File.Open(fileName, FileMode.Open))
            {
                using (var reader = new BinaryReader(stream, Encoding.UTF8, false))
                {
                    aspectRatio = reader.ReadSingle();
                    tempDirectory = reader.ReadString();
                    autoSaveTime = reader.ReadInt32();
                    showStatusBar = reader.ReadBoolean();
                }
            }

            Console.WriteLine("Aspect ratio set to: " + aspectRatio);
            Console.WriteLine("Temp directory is: " + tempDirectory);
            Console.WriteLine("Auto save time set to: " + autoSaveTime);
            Console.WriteLine("Show status bar: " + showStatusBar);
        }
    }
}

open System.IO
open System.Text

let fileName = "AppSettings.dat"

let writeDefaultValues () =
    use stream = File.Open(fileName, FileMode.Create)
    use writer = new BinaryWriter(stream, Encoding.UTF8, false)
    writer.Write 1.250F
    writer.Write @"c:\Temp"
    writer.Write 10
    writer.Write true

let displayValues () =
    if File.Exists fileName then
        use stream = File.Open(fileName, FileMode.Open)
        use reader = new BinaryReader(stream, Encoding.UTF8, false)
        let aspectRatio = reader.ReadSingle()
        let tempDirectory = reader.ReadString()
        let autoSaveTime = reader.ReadInt32()
        let showStatusBar = reader.ReadBoolean()

        printfn $"Aspect ratio set to: {aspectRatio}"
        printfn $"Temp directory is: {tempDirectory}"
        printfn $"Auto save time set to: {autoSaveTime}"
        printfn $"Show status bar: {showStatusBar}"

writeDefaultValues ()
displayValues ()

Imports System.IO

Module Module1
    Const fileName As String = "AppSettings.dat"

    Sub Main()
        WriteDefaultValues()
        DisplayValues()
    End Sub

    Sub WriteDefaultValues()
        Using writer As BinaryWriter = New BinaryWriter(File.Open(fileName, FileMode.Create))
            writer.Write(1.25F)
            writer.Write("c:\Temp")
            writer.Write(10)
            writer.Write(True)
        End Using
    End Sub

    Sub DisplayValues()
        Dim aspectRatio As Single
        Dim tempDirectory As String
        Dim autoSaveTime As Integer
        Dim showStatusBar As Boolean

        If (File.Exists(fileName)) Then

            Using reader As BinaryReader = New BinaryReader(File.Open(fileName, FileMode.Open))
                aspectRatio = reader.ReadSingle()
                tempDirectory = reader.ReadString()
                autoSaveTime = reader.ReadInt32()
                showStatusBar = reader.ReadBoolean()
            End Using

            Console.WriteLine("Aspect ratio set to: " & aspectRatio)
            Console.WriteLine("Temp directory is: " & tempDirectory)
            Console.WriteLine("Auto save time set to: " & autoSaveTime)
            Console.WriteLine("Show status bar: " & showStatusBar)
        End If
    End Sub

End Module

Remarks

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

Applies to

Write(Int32)

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Source:: BinaryWriter.cs

Writes a four-byte signed integer to the current stream and advances the stream position by four bytes.

public:
 virtual void Write(int value);

public virtual void Write (int value);

abstract member Write : int -> unit
override this.Write : int -> unit

Public Overridable Sub Write (value As Integer)

Parameters

value: Int32

The four-byte signed integer to write.

Exceptions

IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

Examples

The following code example demonstrates how to store and retrieve application settings in a file.

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

class ConsoleApplication
{
    const string fileName = "AppSettings.dat";

    static void Main()
    {
        WriteDefaultValues();
        DisplayValues();
    }

    public static void WriteDefaultValues()
    {
        using (var stream = File.Open(fileName, FileMode.Create))
        {
            using (var writer = new BinaryWriter(stream, Encoding.UTF8, false))
            {
                writer.Write(1.250F);
                writer.Write(@"c:\Temp");
                writer.Write(10);
                writer.Write(true);
            }
        }
    }

    public static void DisplayValues()
    {
        float aspectRatio;
        string tempDirectory;
        int autoSaveTime;
        bool showStatusBar;

        if (File.Exists(fileName))
        {
            using (var stream = File.Open(fileName, FileMode.Open))
            {
                using (var reader = new BinaryReader(stream, Encoding.UTF8, false))
                {
                    aspectRatio = reader.ReadSingle();
                    tempDirectory = reader.ReadString();
                    autoSaveTime = reader.ReadInt32();
                    showStatusBar = reader.ReadBoolean();
                }
            }

            Console.WriteLine("Aspect ratio set to: " + aspectRatio);
            Console.WriteLine("Temp directory is: " + tempDirectory);
            Console.WriteLine("Auto save time set to: " + autoSaveTime);
            Console.WriteLine("Show status bar: " + showStatusBar);
        }
    }
}

open System.IO
open System.Text

let fileName = "AppSettings.dat"

let writeDefaultValues () =
    use stream = File.Open(fileName, FileMode.Create)
    use writer = new BinaryWriter(stream, Encoding.UTF8, false)
    writer.Write 1.250F
    writer.Write @"c:\Temp"
    writer.Write 10
    writer.Write true

let displayValues () =
    if File.Exists fileName then
        use stream = File.Open(fileName, FileMode.Open)
        use reader = new BinaryReader(stream, Encoding.UTF8, false)
        let aspectRatio = reader.ReadSingle()
        let tempDirectory = reader.ReadString()
        let autoSaveTime = reader.ReadInt32()
        let showStatusBar = reader.ReadBoolean()

        printfn $"Aspect ratio set to: {aspectRatio}"
        printfn $"Temp directory is: {tempDirectory}"
        printfn $"Auto save time set to: {autoSaveTime}"
        printfn $"Show status bar: {showStatusBar}"

writeDefaultValues ()
displayValues ()

Imports System.IO

Module Module1
    Const fileName As String = "AppSettings.dat"

    Sub Main()
        WriteDefaultValues()
        DisplayValues()
    End Sub

    Sub WriteDefaultValues()
        Using writer As BinaryWriter = New BinaryWriter(File.Open(fileName, FileMode.Create))
            writer.Write(1.25F)
            writer.Write("c:\Temp")
            writer.Write(10)
            writer.Write(True)
        End Using
    End Sub

    Sub DisplayValues()
        Dim aspectRatio As Single
        Dim tempDirectory As String
        Dim autoSaveTime As Integer
        Dim showStatusBar As Boolean

        If (File.Exists(fileName)) Then

            Using reader As BinaryReader = New BinaryReader(File.Open(fileName, FileMode.Open))
                aspectRatio = reader.ReadSingle()
                tempDirectory = reader.ReadString()
                autoSaveTime = reader.ReadInt32()
                showStatusBar = reader.ReadBoolean()
            End Using

            Console.WriteLine("Aspect ratio set to: " & aspectRatio)
            Console.WriteLine("Temp directory is: " & tempDirectory)
            Console.WriteLine("Auto save time set to: " & autoSaveTime)
            Console.WriteLine("Show status bar: " & showStatusBar)
        End If
    End Sub

End Module

Remarks

BinaryWriter stores this data type in little endian format.

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

Applies to

Jaa

BinaryWriter.Write Method

Definition

Overloads

Write(Char[], Int32, Int32)

Parameters

Exceptions

Examples

Remarks

See also

Applies to

Write(Byte[], Int32, Int32)

Parameters

Exceptions

Examples

Remarks

See also

Applies to

Write(UInt64)

Parameters

Exceptions

Remarks

See also

Applies to

Write(UInt32)

Parameters

Exceptions

Remarks

See also

Applies to

Write(UInt16)

Parameters

Exceptions

Remarks

See also

Applies to

Write(String)

Parameters

Exceptions

Examples

Remarks

See also

Applies to

Write(Single)

Parameters

Exceptions

Examples

Remarks

See also

Applies to

Write(SByte)

Parameters

Exceptions

Remarks

See also

Applies to

Write(ReadOnlySpan<Char>)

Parameters

Applies to

Write(ReadOnlySpan<Byte>)

Parameters

Applies to

Write(Int64)

Parameters

Exceptions

Remarks

See also

Applies to

Write(Char[])

Parameters

Exceptions

Examples

Remarks

See also

Applies to

Write(Int16)

Parameters

Exceptions

Remarks

See also