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Socket.Available Property

Gets the amount of data that has been received from the network and is available to be read.

Namespace:  System.Net.Sockets
Assembly:  System (in System.dll)

public int Available { get; }

Property Value

Type: System.Int32
The number of bytes of data received from the network and available to be read.

ExceptionCondition
SocketException

An error occurred when attempting to access the socket. See the Remarks section for more information.

ObjectDisposedException

The Socket has been closed.

If you are using a non-blocking Socket, Available is a good way to determine whether data is queued for reading, before calling Receive. The available data is the total amount of data queued in the network buffer for reading. If no data is queued in the network buffer, Available returns 0.

If the remote host shuts down or closes the connection, Available can throw a SocketException. If you receive a SocketException, use the SocketException.ErrorCode property to obtain the specific error code. After you have obtained this code, refer to the Windows Sockets version 2 API error code documentation in the MSDN library for a detailed description of the error.

NoteNote:

This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing.

The following code example compares the results of calling IOControl with FIONREAD and the Available property.

// FIONREAD is also available as the "Available" property.
public const int FIONREAD   = 0x4004667F;

static void DisplayPendingByteCount(Socket s)
 {
     byte[] outValue = BitConverter.GetBytes(0);

     // Check how many bytes have been received.
     s.IOControl(FIONREAD, null, outValue);

     uint bytesAvailable = BitConverter.ToUInt32(outValue, 0);
     Console.WriteLine("server has {0} bytes pending. Available property says {1}.",
         bytesAvailable, s.Available);

     return;
 }
// FIONREAD is also available as the "Available" property.
const int FIONREAD   = 0x4004667F;

void DisplayPendingByteCount(Socket* s)
{
    Byte outValue[] = BitConverter::GetBytes(0);

    // Check how many bytes have been received.
    s->IOControl(FIONREAD, 0, outValue);

    UInt32 bytesAvailable = BitConverter::ToUInt32(outValue, 0);
    Console::WriteLine(S"server has {0} bytes pending. Available property says {1}.", __box(bytesAvailable), __box(s->Available));

    return;
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

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