套接字BeginReceive问题

Question

为什么Size的BeginReceive方法(第三个参数)出错？

但是BUFFER_SIZE的长度永远不会大于常量值(它的2048字节)。

这是我的代码：

public void Send(byte[] byteData, M.StateObject _stateObj, Socket client)
    {
        // Begin sending the data to the remote client(s):
        client.BeginSend(byteData, 0, byteData.Length, 0, new AsyncCallback(SendData), _stateObj);
    }

    void SendData(IAsyncResult ar)
    {
        try
        {
            M.StateObject stateObj = (M.StateObject)ar.AsyncState;
            Socket client = stateObj.server;
            byte[] data = stateObj.data;
            int bytesSent = client.EndSend(ar);
            client.BeginReceive(data, 0, M.StateObject.BUFFER_SIZE, SocketFlags.None, new AsyncCallback(ReceiveData), stateObj);
            allDone.Set();
        }
        catch (Exception ex)
        {
            OnMessageShowing(ex.Message);
        }
    }

    private void ClientLogging(object _data, M.StateObject _stateObj)
    {
        M.UserData client = _data as M.UserData;
        if (client != null)
        {
            //setting properties:
            client.bConnectred = true;

            // 1. add client to list of clients:
            ClientAddingRemoving(_stateObj, client, true);

            // 2. showing welcome on server
            OnMessageShowing(client.ServerNotifying());

            // 3. refreshing the list of clients on server`s main form
            OnClientsListRefreshing(bll.ClientsListCreating(listOfClients));

            // 4. send welcome note to all clients:
            byte[] bytesToSend = M.SerializeServer.Login_WelcomeToAllClients(client);
            bytesToSend = M.BytesArrayGetSet.BytesSending_Set(bytesToSend);
            SendToAll(bytesToSend, _stateObj.server);

            // 5. send list of all users to logged client:
            bytesToSend = M.SerializeServer.Login_ToLoggedClient(bll.ListOfAllUsers(listOfClients));
            bytesToSend = M.BytesArrayGetSet.BytesSending_Set(bytesToSend);
            Send(bytesToSend, _stateObj, _stateObj.server);

            //6. send new client to list of all other clients:
            bytesToSend = M.SerializeServer.Login_ToAllClients(client);
            bytesToSend = M.BytesArrayGetSet.BytesSending_Set(bytesToSend);
            SendToAll(bytesToSend, _stateObj.server);
        }
    }

    private void SendToAll(byte[] data, Socket _socket)
    {
        foreach (M.StateObject stObj in listOfClients.Keys) //dictionary<StateObject, Client>, Client is a custom client class
        {
            Send(data, stObj, _socket);
        }
    }

下面是StateObject类：

public class StateObject 
{    
    public Socket Server;
    public const int BUFFER_SIZE = 2048;
    public byte[] data = new byte[BUFFER_SIZE];
}

也许调用Send()方法的次数太多了？我是否必须使用"ManualResetEvent“委托来阻塞或做其他事情？我真的不知道该怎么办。

Answer 1

用stateObj.data.Length替换M.StateObject.BUFFER_SIZE，因为data比BUFFER_SIZE小。

我还看到你把数据放到一个数组中，但是不要对它做任何事情。我建议你改一下这个

byte[] data = stateObj.data;
int bytesSent = client.EndSend(ar);
client.BeginReceive(data, 0, M.StateObject.BUFFER_SIZE, SocketFlags.None, new AsyncCallback(ReceiveData), stateObj);

到这个

int bytesSent = client.EndSend(ar);
client.BeginReceive(stateObj.data, 0, stateObj.data.Length, SocketFlags.None, new AsyncCallback(ReceiveData), stateObj);

看看这是否能修复您的错误。

另外，我注意到您的BeginSend传入了状态对象blob。您用来发送数据的数组也是stateObj.data吗？如果是这样，对BeginSend的多个调用是否使用了新的stateObj对象？如果它们都共享相同的状态对象，则可以让下一个发送在当前接收正在写入的同时读取。