.NET Documentation

UdpClient.Send Method

Sends UDP data to a remote host. This is a convenience method that uses the default remote host and port if they have been set using the Connect method.

Overloads

• public int Send(byte[] datagram)

  Sends a UDP datagram to the host and port specified by the Connect method.

• public int Send(byte[] datagram, int bytes)

  Sends a specified number of bytes from the UDP datagram to the host and port specified by the Connect method.

Parameters

Return Value

The number of bytes sent to the socket.

Exceptions

Remarks

The Send method sends UDP datagrams. If you have not previously called the Connect method, the Send method will throw a SocketException.

To send to a specific remote host and port without establishing a connection, use the SendTo method.

Example

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

public class UdpSender
{
    public static void Main(string[] args)
    {
        try
        {
            // Define the remote endpoint (IP address and port)
            IPAddress ipAddress = IPAddress.Parse("127.0.0.1");
            int port = 11000;
            IPEndPoint remoteEndPoint = new IPEndPoint(ipAddress, port);

            // Create a UdpClient instance
            using (UdpClient udpClient = new UdpClient())
            {
                // Connect to the remote endpoint
                udpClient.Connect(remoteEndPoint);

                // Data to send
                string message = "Hello, UDP!";
                byte[] sendBytes = Encoding.ASCII.GetBytes(message);

                // Send the data
                int bytesSent = udpClient.Send(sendBytes, sendBytes.Length);

                Console.WriteLine($"Sent {bytesSent} bytes to {remoteEndPoint}.");
            }
        }
        catch (Exception e)
        {
            Console.WriteLine($"Error: {e.Message}");
        }
    }
}