C# 发送通知客户端

我想通过调用另一个方法向订阅者（订阅者的ip地址在服务器端的数据库中）发送通知（比如字符串）。每当我调用该方法时，输出都会出现一些错误

[WebMethod]
public string GetGroupPath(string emailAddress, string password, string ipAddress)
{
    //SqlDataAdapter dbadapter = null;
    DataSet returnDS = new DataSet();
    string groupName = null;
    string groupPath = null;

    SqlConnection dbconn = new SqlConnection("Server = localhost;Database=server;User ID = admin;Password = password;Trusted_Connection=false;");

    dbconn.Open();

    SqlCommand cmd = new SqlCommand();
    string getGroupName = "select users.groupname from users where emailaddress = "+"'"+ emailAddress+"'"+ " and "+ "users.password = " + "'" +password+"'";
    cmd.CommandText = getGroupName;
    cmd.Connection = dbconn;
    SqlDataReader reader = null;
    try
    {
        reader = cmd.ExecuteReader();
        while (reader.Read())
        {
            groupName = reader["groupname"].ToString();
        }
    }
    catch (Exception)
    {
        groupPath = "Invalied";
    }


    dbconn.Close();
    dbconn.Open();

    if (groupName != null)
    {
        string getPath = "select groups.grouppath from groups where groupname = " + "'" + groupName + "'";
        cmd.CommandText = getPath;
        cmd.Connection = dbconn;

        try
        {
            reader = cmd.ExecuteReader();
            while (reader.Read())
            {
                groupPath = reader["grouppath"].ToString();
            }
        }
        catch
        {
            groupPath = "Invalied";
        }
    }
    else
        groupPath = "Invalied";
    dbconn.Close();


    if (groupPath != "Invalied") 
    {
        dbconn.Open();
        string getPath = "update users set users.ipaddress = "+"'"+ipAddress+"'"+" where users.emailaddress = " + "'" + emailAddress + "'";
        cmd.CommandText = getPath;
        cmd.Connection = dbconn; 
        cmd.ExecuteNonQuery();
        dbconn.Close();

    }

    NotifyUsers();
    //NotifyUsers nu = new NotifyUsers();
    //List<string> ipList = new List<string>();
    //ipList.Add("192.168.56.1");

    //nu.Notify();

    return groupPath;
}

private void NotifyUsers() 
{
    Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
    byte[] ipb = Encoding.ASCII.GetBytes("255.255.255.255");
    IPAddress ipAddress = new IPAddress(ipb);

    IPEndPoint endPoint = new IPEndPoint(ipAddress, 15000);
    string notification = "new_update";
    byte[] sendBuffer = Encoding.ASCII.GetBytes(notification);
    sock.SendTo(sendBuffer, endPoint);
    sock.Close();  
}

谢谢：）因为这是我的第一篇帖子，请也给我一个更好的反馈：）

---

thaks

在通知中尝试以下代码，然后禁用防火墙设置

try
{
    // Establish the remote endpoint for the socket.

    // This example uses port 11000 on the local computer.
    IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName())

    Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

    IPAddress ipAddress = ipHostInfo.AddressList[0];
    IPEndPoint remoteEP = new IPEndPoint(ipAddress,15000);
    string notification = "new_update";
    byte[] sendBuffer = Encoding.ASCII.GetBytes(notification);
    sock.SendTo(sendBuffer, remoteEP );
    sock.Close();  
}
catch() {}

---

希望这能解决问题。

只是想补充一点

byte[] ipb = Encoding.ASCII.GetBytes("255.255.255.255");
IPAddress ipAddress = new IPAddress(ipb);

可以简化为

IPAddress.Broadcast

或者，如果您想使用另一个IP地址，也可以使用.Parse（）

更新：

实际上

Encoding.ASCII.GetBytes（“255.255.255.255”）将给您一个完全不同的结果

var bytes = Encoding.ASCII.GetBytes("255.255.255.255");

// bytes returns something like
// new byte[] { 50, 53, 53, 46... }

// what you want is
var bytes = new byte[] { 255, 255, 255, 255 };

在这样的问题中包含异常总是一个好主意-帮助人们准确地缩小问题的范围…还请考虑此代码的SQL注入安全问题，考虑使用参数化SQL或存储过程或ORM。SQL注入在这里是正确的。我只是想先解决这个问题。好的，我已经解决了这个问题。有人知道我应该在byte[]ipb=Encoding.ASCII.GetBytes（“255.255.255.255”）行中使用什么ip地址吗；我使用过localhost（127.0.0.1），但没有使用。客户端也在同一台机器上运行。谢谢
var ip = IPAddress.Parse("192.168.1.1");

var bytes = Encoding.ASCII.GetBytes("255.255.255.255");

// bytes returns something like
// new byte[] { 50, 53, 53, 46... }

// what you want is
var bytes = new byte[] { 255, 255, 255, 255 };