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FileStream.Write Method

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Definition

Namespace:
System.IO
Assembly:
System.Runtime.dll
Assembly:
netstandard.dll
Assemblies:
mscorlib.dll, System.IO.FileSystem.dll
Assembly:
System.IO.FileSystem.dll
Assembly:
mscorlib.dll

Overloads

Write(ReadOnlySpan<Byte>)

Writes a sequence of bytes from a read-only span to the current file stream and advances the current position within this file stream by the number of bytes written.
Write(Byte[], Int32, Int32)

Writes a block of bytes to the file stream.

Write(ReadOnlySpan<Byte>)

Source:
FileStream.cs
Source:
FileStream.cs
Source:
FileStream.cs

Writes a sequence of bytes from a read-only span to the current file stream and advances the current position within this file stream by the number of bytes written.

public:
 override void Write(ReadOnlySpan<System::Byte> buffer);
public override void Write (ReadOnlySpan<byte> buffer);
override this.Write : ReadOnlySpan<byte> -> unit
Public Overrides Sub Write (buffer As ReadOnlySpan(Of Byte))

Parameters

buffer
ReadOnlySpan<Byte>

A region of memory. This method copies the contents of this region to the current file stream.

Exceptions

IOException

.NET 8 and later versions: The underlying pipe is closed or disconnected.

Remarks

Use the CanWrite property to determine whether the current instance supports writing. Use the WriteAsync method to write asynchronously to the current stream.

If the write operation is successful, the position within the file stream advances by the number of bytes written. If an exception occurs, the position within the file stream remains unchanged.

Applies to

Write(Byte[], Int32, Int32)

Source:
FileStream.cs
Source:
FileStream.cs
Source:
FileStream.cs

Writes a block of bytes to the file stream.

public:
 override void Write(cli::array <System::Byte> ^ array, int offset, int count);
public:
 override void Write(cli::array <System::Byte> ^ buffer, int offset, int count);
public override void Write (byte[] array, int offset, int count);
public override void Write (byte[] buffer, int offset, int count);
override this.Write : byte[] * int * int -> unit
override this.Write : byte[] * int * int -> unit
Public Overrides Sub Write (array As Byte(), offset As Integer, count As Integer)
Public Overrides Sub Write (buffer As Byte(), offset As Integer, count As Integer)

Parameters

arraybuffer
Byte[]

The buffer containing data to write to the stream.

offset
Int32

The zero-based byte offset in array from which to begin copying bytes to the stream.

count
Int32

The maximum number of bytes to write.

Exceptions

ArgumentNullException

array is null.

ArgumentException

offset and count describe an invalid range in array.

ArgumentOutOfRangeException

offset or count is negative.

IOException

An I/O error occurred.

-or-

Another thread may have caused an unexpected change in the position of the operating system's file handle.

-or-

.NET 8 and later versions: The underlying pipe is closed or disconnected.

ObjectDisposedException

The stream is closed.

NotSupportedException

The current stream instance does not support writing.

Examples

This code example is part of a larger example provided for the Lock method.

// Write the original file data.
if ( fileStream->Length == 0 )
{
   tempString = String::Concat( lastRecordText, recordNumber.ToString() );
   fileStream->Write( uniEncoding->GetBytes( tempString ), 0, uniEncoding->GetByteCount( tempString ) );
}

// Write the original file data.
if(fileStream.Length == 0)
{
    tempString =
        lastRecordText + recordNumber.ToString();
    fileStream.Write(uniEncoding.GetBytes(tempString),
        0, uniEncoding.GetByteCount(tempString));
}

// Write the original file data.
if fileStream.Length = 0 then
    let tempString = lastRecordText + string recordNumber
    fileStream.Write(uniEncoding.GetBytes tempString, 0, uniEncoding.GetByteCount tempString)

' Write the original file data.
If aFileStream.Length = 0 Then
    tempString = _
        lastRecordText + recordNumber.ToString()
    aFileStream.Write(uniEncoding.GetBytes(tempString), _
        0, uniEncoding.GetByteCount(tempString))
End If

Remarks

This method overrides Write.

The offset parameter gives the offset of the byte in array (the buffer index) at which to begin copying, and the count parameter gives the number of bytes that will be written to the stream. If the write operation is successful, the current position of the stream is advanced by the number of bytes written. If an exception occurs, the current position of the stream is unchanged.

Note

Use the CanWrite property to determine whether the current instance supports writing. For additional information, see CanWrite.

Do not interrupt a thread that's performing a write operation. Although the application may appear to run successfully after the thread is unblocked, the interruption can decrease your application's performance and reliability.

For a list of common file and directory operations, see Common I/O Tasks.

See also

Applies to