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TcpClient.GetStream Method

Returns the NetworkStream used to send and receive data.

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

public NetworkStream GetStream ()
public NetworkStream GetStream ()
public function GetStream () : NetworkStream
Not applicable.

Return Value

The underlying NetworkStream.

Exception typeCondition

InvalidOperationException

The TcpClient is not connected to a remote host.

ObjectDisposedException

The TcpClient has been closed.

GetStream returns a NetworkStream that you can use to send and receive data. The NetworkStream class inherits from the Stream class, which provides a rich collection of methods and properties used to facilitate network communications.

You must call the Connect method first, or the GetStream method will throw an InvalidOperationException. After you have obtained the NetworkStream, call the Write method to send data to the remote host. Call the Read method to receive data arriving from the remote host. Both of these methods block until the specified operation is performed. You can avoid blocking on a read operation by checking the DataAvailable property. A true value means that data has arrived from the remote host and is available for reading. In this case, Read is guaranteed to complete immediately. If the remote host has shutdown its connection, Read will immediately return with zero bytes.

NoteNote:

You must close the NetworkStream when you are through sending and receiving data. Closing TcpClient does not release the NetworkStream.

NoteNote:

If you receive a SocketException, use SocketException.ErrorCode to obtain the specific error code. After you have obtained this code, you can refer to the Windows Sockets version 2 API error code documentation in MSDN 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 uses GetStream to obtain the underlying NetworkStream. After obtaining the NetworkStream, it sends and receives using its Write and Read methods.

TcpClient tcpClient = new TcpClient ();

// Uses the GetStream public method to return the NetworkStream.
NetworkStream netStream = tcpClient.GetStream ();

if (netStream.CanWrite)
{
    Byte[] sendBytes = Encoding.UTF8.GetBytes ("Is anybody there?");
    netStream.Write (sendBytes, 0, sendBytes.Length);
}
else
{
    Console.WriteLine ("You cannot write data to this stream.");
    tcpClient.Close ();

    // Closing the tcpClient instance does not close the network stream.
    netStream.Close ();
    return;
}

if (netStream.CanRead)
{
    // Reads NetworkStream into a byte buffer.
    byte[] bytes = new byte[tcpClient.ReceiveBufferSize];

    // Read can return anything from 0 to numBytesToRead. 
    // This method blocks until at least one byte is read.
    netStream.Read (bytes, 0, (int)tcpClient.ReceiveBufferSize);

    // Returns the data received from the host to the console.
    string returndata = Encoding.UTF8.GetString (bytes);

    Console.WriteLine ("This is what the host returned to you: " + returndata);
    
}
else
{
    Console.WriteLine ("You cannot read data from this stream.");
    tcpClient.Close ();

    // Closing the tcpClient instance does not close the network stream.
    netStream.Close ();
    return;
}
netStream.Close();


TcpClient tcpClient = new TcpClient();

// Uses the GetStream public method to return the NetworkStream.
NetworkStream netStream = tcpClient.GetStream();

if (netStream.get_CanWrite()) {
    ubyte sendBytes[] =
        Encoding.get_UTF8().GetBytes("Is anybody there?");
    netStream.Write(sendBytes, 0, sendBytes.length);
}
else {
    Console.WriteLine("You cannot write data to this stream.");
    tcpClient.Close();
    // Closing the tcpClient instance does not close the network stream.
    netStream.Close();
    return;
}

if (netStream.get_CanRead()) {
    // Reads NetworkStream into a byte buffer.
    ubyte bytes[] = new ubyte[tcpClient.get_ReceiveBufferSize()];

    // Read can return anything from 0 to numBytesToRead. 
    // This method blocks until at least one byte is read.
    netStream.Read(bytes, 0, (int)tcpClient.get_ReceiveBufferSize());

    // Returns the data received from the host to the console.
    String returnData = Encoding.get_UTF8().GetString(bytes);

    Console.WriteLine("This is what the host returned to you: "
        + returnData);
}
else {
    Console.WriteLine("You cannot read data from this stream.");
    tcpClient.Close();

    // Closing the tcpClient instance does not close the network stream.
    netStream.Close();
    return;
}

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

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