UdpClient Class

Namespace: System.Net.Sockets

Assembly: System.Net.Sockets.dll

Overview

Provides support for the User Datagram Protocol (UDP).

The UdpClient class provides access to the UDP protocol, which is a connectionless protocol that sends datagrams without establishing a connection.

Table of Contents

• Constructors
• Properties
• Methods
• Extension Methods

Constructors

• UdpClient()

  Initializes a new instance of the UdpClient class.

• UdpClient(System.Int32 port)

  Initializes a new instance of the UdpClient class and binds it to the specified local port.

  port

  The local port to bind to.

• UdpClient(System.Net.IPEndPoint localEP)

  Initializes a new instance of the UdpClient class and binds it to the specified local endpoint.

  localEP

  The local endpoint to bind to.

• UdpClient(System.String hostname, System.Int32 port)

  Initializes a new instance of the UdpClient class and connects it to the specified remote host and port.

  hostname

  The hostname of the remote host.

  port

  The port of the remote host.

Properties

• Available() : System.Int32

  Gets the number of bytes available in the message in the network buffer.

  Return Value

  The number of bytes available.

• Client() : System.Net.Sockets.Socket

  Gets or sets the underlying Socket.

  Return Value

  The underlying Socket.

• ExclusiveAddressUse() : System.Boolean

  Gets or sets a value that indicates whether the UdpClient allows another UdpClient to be bound to the same address and port combination.

  Return Value

  true if the UdpClient can bind to the same address and port; otherwise, false.

Methods

• Connect(System.Net.EndPoint remoteEP)

  Connects the UdpClient to a remote host and port.

  remoteEP

  A System.Net.EndPoint that represents the remote host and port to which to connect.

  Remarks

  For UDP, connecting associates the UdpClient with a specific remote host and port. Subsequent send and receive operations will be to and from that remote host and port. You can only have one remote host and port association per UdpClient.

  Exceptions

  • System.Net.Sockets.SocketException: An error occurred while accessing the socket.
• ReceiveAsync() : System.Threading.Tasks.Task<System.Net.Sockets.UdpReceiveResult>

  Asynchronously receives a datagram from the network.

  Return Value

  A task that represents the asynchronous operation. The value of the task contains a UdpReceiveResult object that contains the data received and the endpoint of the sender.

  Remarks

  This method does not block. It returns a Task that can be used to await the result.

  Exceptions

  • System.Net.Sockets.SocketException: An error occurred while accessing the socket.
  • System.ObjectDisposedException: The UdpClient has been closed.
• SendAsync(System.Byte[] datagram, System.Net.EndPoint endPoint) : System.Threading.Tasks.Task<System.Int32>

  Asynchronously sends a UDP datagram to a specified remote host and port.

  datagram

  A System.Byte array containing the data to send.

  endPoint

  A System.Net.EndPoint that represents the host and port to which to send the datagram.

  Return Value

  A task that represents the asynchronous operation. The value of the task contains the number of bytes sent.

  Remarks

  This method does not block. It returns a Task that can be used to await the result.

  Exceptions

  • System.Net.Sockets.SocketException: An error occurred while accessing the socket.
  • System.ObjectDisposedException: The UdpClient has been closed.
• Close()

  Releases the unmanaged resources used by the UdpClient and closes the connection.

  Remarks

  Calling Close releases all resources used by the UdpClient object.

Extension Methods

This class also exposes several useful extension methods, including:

• ReceiveAsync(this UdpClient udpClient) : Task<UdpReceiveResult>

  Provides a task-based asynchronous version of the Receive method.

• SendAsync(this UdpClient udpClient, Byte[] datagram, Int32 bytes, EndPoint remoteEP) : Task<Int32>

  Asynchronously sends a UDP datagram to a specified remote host and port.

For detailed examples and further information, please refer to the UDP Client Sample.