UdpClient使用

public class UdpClientManager
{
    //接收数据事件
    public Action<string> recvMessageEvent = null;
    //发送结果事件
    public Action<int> sendResultEvent = null;
    //本地监听端口
    public int localPort = 0;
 
    private UdpClient udpClient = null;
 
    public UdpClientManager(int localPort)
    {
        if (localPort < 0 || localPort > 65535)
            throw new ArgumentOutOfRangeException("localPort is out of range");
 
        this.localPort = localPort;
    }
 
    public void Start()
    {
        while (true)
        {
            try
            {
                udpClient = new UdpClient(localPort, AddressFamily.InterNetwork);//指定本地监听port
                ReceiveMessage();
                break;
            }
            catch (Exception)
            {
                Thread.Sleep(100);
            }
        }
    }
 
    private async void ReceiveMessage()
    {
        while (true)
        {
            if (udpClient == null)
                return;
 
            try
            {
                UdpReceiveResult udpReceiveResult = await udpClient.ReceiveAsync();
                string message = Encoding.UTF8.GetString(udpReceiveResult.Buffer);
                if (recvMessageEvent != null)
                    recvMessageEvent(message);
            }
            catch (Exception ex)
            {
            }
        }
    }
 
    //单播
    public async void SendMessageByUnicast(string message, string destHost, int destPort)
    {
        if (string.IsNullOrEmpty(message))
            throw new ArgumentNullException("message cant not null");
        if (udpClient == null)
            throw new ArgumentNullException("udpClient cant not null");
        if (string.IsNullOrEmpty(destHost))
            throw new ArgumentNullException("destHost cant not null");
        if (destPort < 0 || destPort > 65535)
            throw new ArgumentOutOfRangeException("destPort is out of range");
 
        byte[] buffer = Encoding.UTF8.GetBytes(message);
        int len = 0;
        for (int i = 0; i < 3; i++)
        {
            try
            {
                len = await udpClient.SendAsync(buffer, buffer.Length, new IPEndPoint(IPAddress.Parse(destHost), destPort));
            }
            catch (Exception)
            {
                len = 0;
            }
 
            if (len <= 0)
                Thread.Sleep(100);
            else
                break;
        }
 
        if (sendResultEvent != null)
            sendResultEvent(len);
    }
 
    public void CloseUdpCliend()
    {
        if (udpClient == null)
            throw new ArgumentNullException("udpClient cant not null");
 
        try
        {
            udpClient.Client.Shutdown(SocketShutdown.Both);
        }
        catch (Exception)
        {
        }
        udpClient.Close();
        udpClient = null;
    }
}
public class UdpClientManager
{
    /