我想通过说明我对UDP广播和多播的理解非常有限来作为序言 . 这是我的第一个项目 .
我有一台在机器和Windows Phone 7应用程序上运行的C#桌面客户端 . WP7应用程序应该通过网络发送UDP广播,桌面客户端应该监听UDP多播并相应地做出响应 . 这仅用于通过网络进行简单的机器发现,以查找运行桌面客户端的计算机 .
C#桌面客户端代码
public class ConnectionListener
{
private const int UDP_PORT = 54322;
private static readonly IPAddress MULTICAST_GROUP_ADDRESS = IPAddress.Parse("224.0.0.1");
private UdpClient _listener;
public ConnectionListener()
{
_listener = new UdpClient(UDP_PORT, AddressFamily.InterNetwork);
_listener.EnableBroadcast = true;
_listener.JoinMulticastGroup(MULTICAST_GROUP_ADDRESS);
_listener.BeginReceive(ReceiveCallback, null);
}
private void ReceiveCallback(IAsyncResult result)
{
IPEndPoint receiveEndpoint = new IPEndPoint(IPAddress.Any, UDP_PORT);
byte[] receivedBytes = _listener.EndReceive(result, ref receiveEndpoint);
byte[] response = Encoding.UTF8.GetBytes("WPF Response");
_listener.BeginSend(response, response.Length, receiveEndpoint, SendCallback, null);
}
private void SendCallback(IAsyncResult result)
{
int sendCount = _listener.EndSend(result);
Console.WriteLine("Sent Count is: " + sendCount);
}
}
WP7服务器代码:
public class MachineDetector
{
public const int UDP_PORT = 54322;
private const string MULTICAST_GROUP_ADDRESS = "224.0.0.1";
UdpAnySourceMulticastClient _client = null;
bool _joined = false;
private byte[] _receiveBuffer;
private const int MAX_MESSAGE_SIZE = 512;
public MachineDetector()
{
_client = new UdpAnySourceMulticastClient(IPAddress.Parse(MULTICAST_GROUP_ADDRESS), UDP_PORT);
_receiveBuffer = new byte[MAX_MESSAGE_SIZE];
_client.BeginJoinGroup(
result =>
{
_client.EndJoinGroup(result);
_client.MulticastLoopback = false;
SendRequest();
}, null);
}
private void SendRequest()
{
byte[] requestData = Encoding.UTF8.GetBytes("WP7 Multicast");
_client.BeginSendToGroup(requestData, 0, requestData.Length,
result =>
{
_client.EndSendToGroup(result);
Receive();
}, null);
}
private void Receive()
{
Array.Clear(_receiveBuffer, 0, _receiveBuffer.Length);
_client.BeginReceiveFromGroup(_receiveBuffer, 0, _receiveBuffer.Length,
result =>
{
IPEndPoint source;
_client.EndReceiveFromGroup(result, out source);
string dataReceived = Encoding.UTF8.GetString(_receiveBuffer, 0, _receiveBuffer.Length);
string message = String.Format("[{0}]: {1}", source.Address.ToString(), dataReceived);
Console.WriteLine(message);
Receive();
}, null);
}
}
我能够通过桌面客户端接收数据,但WP7应用程序似乎无法接收响应 . 我一直在敲打这个问题一段时间,不知道还有什么去看 . 任何帮助都会很棒 .
那么,为什么WP7应用程序没有收到回复的任何建议?
2 回答
我认为问题出在
C# Desktop Client
中ConnectionListener:ReceiveCallback
.而是打电话
这将导致消息被发送到多播地址 . 如需进一步的帮助,请参阅How to: Send and Receive Data in a Multicast Group for Windows Phone.
WP7 needs 要多播到网络,以便在一次扫描中有效地到达所有桌面客户端 . 对于客户端响应,唯一预期的目标是WP7 . 因此,多播在这里没有真正的优势(因为调谐到多播的桌面客户端实际上会忽略它) .
相反,您可以使用
receiveEndpoint
_对ConnectionListener:ReceiveCallback
中的EndReceive
调用填充receiveEndpoint
来向WP7服务器发送unicast
响应 . 建议consideration
用于在MSDN创建多播应用程序 .这样,WP7不再需要
join
用于传入多播的多播组,并且桌面客户端不需要send
多播来响应 .