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私はサーバーなしでダイニングの哲学者の問題を解決するプログラムを書いています。メッセージの受け渡しによって動作するはずです。私のアプリケーションは5回実行してから、お互いに接続し、問題を単独で解決する必要があります。私は各アプリにサーバー側とクライアント側を置き、それらにポート番号を付けました。この画像は、私が何を言っているかが表示されます：私が欲しいのは、クライアント側とサーバ側との間でメッセージを送信しているサーバーからクライアントへの非同期メッセージの送信
https://www.photobox.co.uk/my/photo/full?photo_id=500223105218
。
しかし、私はソケットハンドラによって、サーバ側から非同期メッセージを送信中にエラーが発生しているが。私はそれについて検索
（以下、それを言及した）が、類似した任意のコードを見つけることができなかったので、どのように私は、サーバーから直接メッセージを送ることができます側からクライアント側？
そして、私の考えはどうですか？それは正しい？それは間違っている。
これがうまく機能し、私のコードの一部です：
String status = "Thinking";
Boolean right = false;
Boolean left = false;
// Receiving byte array
byte[] bytes = new byte[1024];
SocketPermission permission;
Socket sListener;
Socket sListener1;
Socket sListener2;
Socket sListener3;
Socket sListener4;
Socket handler1;
Socket handler2;
Socket handler3;
Socket handler4;
Socket handler5;
Socket senderSock;
Socket senderSock1;
Socket senderSock2;
Socket senderSock3;
Socket senderSock4;
public Form1()
{
InitializeComponent();
}
//start button
private void button1_Click(object sender, EventArgs e)
{
try
{
IPEndPoint ipEndPoint=null;
IPEndPoint ipEndPoint1=null;
IPEndPoint ipEndPoint2 = null;
IPEndPoint ipEndPoint3 = null;
IPEndPoint ipEndPoint4 = null;
// Creates one SocketPermission object for access restrictions
permission = new SocketPermission(
NetworkAccess.Accept, // Allowed to accept connections
TransportType.Tcp, // Defines transport types
"", // The IP addresses of local host
SocketPermission.AllPorts // Specifies all ports
);
// Listening Socket object
sListener = null;
sListener1 = null;
sListener2 = null;
sListener3 = null;
sListener4 = null;
// Ensures the code to have permission to access a Socket
permission.Demand();
// Resolves a host name to an IPHostEntry instance
IPHostEntry ipHost = Dns.GetHostEntry("");
// Gets first IP address associated with a localhost
IPAddress ipAddr = ipHost.AddressList[0];
// Creates a network endpoint
if (Sport.Text == "1000")
{
ipEndPoint = new IPEndPoint(ipAddr, Convert.ToInt32(Sport.Text));
}else if (Sport.Text == "1001")
{
ipEndPoint1 = new IPEndPoint(ipAddr, Convert.ToInt32(Sport.Text));
}
else if (Sport.Text == "1002")
{
ipEndPoint2 = new IPEndPoint(ipAddr, Convert.ToInt32(Sport.Text));
}
else if (Sport.Text == "1003")
{
ipEndPoint3 = new IPEndPoint(ipAddr, Convert.ToInt32(Sport.Text));
}
else if (Sport.Text == "1004")
{
ipEndPoint4 = new IPEndPoint(ipAddr, Convert.ToInt32(Sport.Text));
}
// Associates a Socket with a local endpoint
if (Sport.Text == "1000")
{
// Create one Socket object to listen the incoming connection
sListener = new Socket(
ipAddr.AddressFamily,
SocketType.Stream,
ProtocolType.Tcp
);
sListener.Bind(ipEndPoint);
sListener.Listen(10);
}else if(Sport.Text == "1001")
{
sListener1 = new Socket(
ipAddr.AddressFamily,
SocketType.Stream,
ProtocolType.Tcp
);
sListener1.Bind(ipEndPoint1);
sListener1.Listen(10);
}
else if (Sport.Text == "1002")
{
sListener2 = new Socket(
ipAddr.AddressFamily,
SocketType.Stream,
ProtocolType.Tcp
);
sListener2.Bind(ipEndPoint2);
sListener2.Listen(10);
}
else if (Sport.Text == "1003")
{
sListener3 = new Socket(
ipAddr.AddressFamily,
SocketType.Stream,
ProtocolType.Tcp
);
sListener3.Bind(ipEndPoint3);
sListener3.Listen(10);
}
else if (Sport.Text == "1004")
{
sListener4 = new Socket(
ipAddr.AddressFamily,
SocketType.Stream,
ProtocolType.Tcp
);
sListener4.Bind(ipEndPoint4);
sListener4.Listen(10);
}
label3.Text = "Server started.";
statusLabel.Text = "READY";
button1.Enabled = false;
}
catch (Exception exc) { MessageBox.Show(exc.ToString()); }
}
//connect button
private void button2_Click(object sender, EventArgs e)
{
try
{
IPEndPoint ipEndPoint = null;
IPEndPoint ipEndPoint1 = null;
IPEndPoint ipEndPoint2 = null;
IPEndPoint ipEndPoint3 = null;
IPEndPoint ipEndPoint4 = null;
// Create one SocketPermission for socket access restrictions
SocketPermission permission = new SocketPermission(
NetworkAccess.Connect, // Connection permission
TransportType.Tcp, // Defines transport types
"", // Gets the IP addresses
SocketPermission.AllPorts // All ports
);
// Ensures the code to have permission to access a Socket
permission.Demand();
// Resolves a host name to an IPHostEntry instance
IPHostEntry ipHost = Dns.GetHostEntry("");
// Gets first IP address associated with a localhost
IPAddress ipAddr = ipHost.AddressList[0];
// Creates a network endpoint
if (Cport.Text == "1000")
{
ipEndPoint = new IPEndPoint(ipAddr, Convert.ToInt32(Cport.Text));
}else if (Cport.Text == "1001")
{
ipEndPoint1 = new IPEndPoint(ipAddr, Convert.ToInt32(Cport.Text));
}
else if (Cport.Text == "1002")
{
ipEndPoint2 = new IPEndPoint(ipAddr, Convert.ToInt32(Cport.Text));
}
else if (Cport.Text == "1003")
{
ipEndPoint3 = new IPEndPoint(ipAddr, Convert.ToInt32(Cport.Text));
}
else if (Cport.Text == "1004")
{
ipEndPoint4 = new IPEndPoint(ipAddr, Convert.ToInt32(Cport.Text));
}
if (Cport.Text == "1000")//A
{
// Create one Socket object to setup Tcp connection
senderSock = new Socket(
ipAddr.AddressFamily,// Specifies the addressing scheme
SocketType.Stream, // The type of socket
ProtocolType.Tcp // Specifies the protocols
);
senderSock.NoDelay = false; // Using the Nagle algorithm
// Establishes a connection to a remote host
senderSock.Connect(ipEndPoint);
statusLabel.Text = "Socket connected to " + senderSock.RemoteEndPoint.ToString();
}
else if (Cport.Text == "1001")//B
{
senderSock1 = new Socket(
ipAddr.AddressFamily,
SocketType.Stream,
ProtocolType.Tcp
);
senderSock1.NoDelay = false;
senderSock1.Connect(ipEndPoint1);
statusLabel.Text = "Socket connected to " + senderSock1.RemoteEndPoint.ToString();
}
else if (Cport.Text == "1002")//C
{
senderSock2 = new Socket(
ipAddr.AddressFamily,
SocketType.Stream,
ProtocolType.Tcp
);
senderSock2.NoDelay = false;
senderSock2.Connect(ipEndPoint2);
statusLabel.Text = "Socket connected to " + senderSock2.RemoteEndPoint.ToString();
}
else if (Cport.Text == "1003")//D
{
senderSock3 = new Socket(
ipAddr.AddressFamily,
SocketType.Stream,
ProtocolType.Tcp
);
senderSock3.NoDelay = false;
senderSock3.Connect(ipEndPoint3);
statusLabel.Text = "Socket connected to " + senderSock3.RemoteEndPoint.ToString();
}
else if (Cport.Text == "1004")//E
{
senderSock4 = new Socket(
ipAddr.AddressFamily,
SocketType.Stream,
ProtocolType.Tcp
);
senderSock4.NoDelay = false;
senderSock4.Connect(ipEndPoint4);
statusLabel.Text = "Socket connected to " + senderSock4.RemoteEndPoint.ToString();
}
button2.Enabled = false;
}
catch (Exception exc) { MessageBox.Show(exc.ToString()); }
label3.Text = "wait...";
Thread.Sleep(4000);
send_st();
}
そして、ここでは、私はエラーを取得する私のコードである「送信（handler1、ステータス）;」
//send status from clnt to server
public void sendCToS(String str)
{
try
{
// Sending message
//<Client Quit> is the sign for end of data
byte[] msg = Encoding.Unicode.GetBytes(str + "<Client Quit>");
// Sends data to a connected Socket.
//send status from client to server
int bytesSend = senderSock.Send(msg);//receiver server tasmim giri va response send mikone
}
catch (Exception exc) { MessageBox.Show(exc.ToString()); }
}
//it send hungry status from both to both!
public void send_st()
{
// Resolves a host name to an IPHostEntry instance
IPHostEntry ipHost = Dns.GetHostEntry("");
// Gets first IP address associated with a localhost
IPAddress ipAddr = ipHost.AddressList[0];
Random rnd = new Random();
int delay = rnd.Next(2000, 5000);
while (true)
{
//System.Threading.Thread.Sleep(2000);
statusLabel.Text = status;
statusLabel.ForeColor = System.Drawing.Color.Blue;
Thread.Sleep(delay);
if (Sport.Text == "1000")//A
{
status = "hungry";
statusLabel.Text = "HUNGRY";
statusLabel.ForeColor = System.Drawing.Color.Red;
//send status from server to clint
Send(handler1, status);
//send status from clnt to server
sendCToS(status);
label3.Text = "status Sent to left and right";
}
else if (Sport.Text == "1001")//B
{
Thread.Sleep(2000);
status = "hungry";
statusLabel.Text = "HUNGRY";
statusLabel.ForeColor = System.Drawing.Color.Red;
//send status from server to clint
Send(handler2, status);
//send status from clnt to server
sendCToS(status);
label3.Text = "status Sent to left and right";
}
else if (Sport.Text == "1002")//C
{
status = "hungry";
statusLabel.Text = "HUNGRY";
statusLabel.ForeColor = System.Drawing.Color.Red;
//send status from server to clint
Send(handler3, status);
//send status from clnt to server
sendCToS(status);
label3.Text = "status Sent to left and right";
}
else if (Sport.Text == "1003")//D
{
Thread.Sleep(2000);
status = "hungry";
statusLabel.Text = "HUNGRY";
statusLabel.ForeColor = System.Drawing.Color.Red;
//send status from server to clint
Send(handler4, status);
//send status from clnt to server
sendCToS(status);
label3.Text = "status Sent to left and right";
}
else if (Sport.Text == "1004")//E
{
Thread.Sleep(3000);
status = "hungry";
statusLabel.Text = "HUNGRY";
statusLabel.ForeColor = System.Drawing.Color.Red;
//send status from server to clint
Send(handler5, status);
//send status from clnt to server
sendCToS(status);
label3.Text = "status Sent to left and right";
}
}
}
//server side
// Thread signal.
public static ManualResetEvent allDone = new ManualResetEvent(false);
public void AcceptCallback(IAsyncResult ar)
{
Socket listener = null;
// A new Socket to handle remote host communication
Socket handler = null;
try
{
// Receiving byte array
byte[] buffer = new byte[1024];
// Get Listening Socket object
listener = (Socket)ar.AsyncState;
// Create a new socket
handler = listener.EndAccept(ar);
// Using the Nagle algorithm
handler.NoDelay = false;
StateObject state = new StateObject();
// Begins to asynchronously receive data
handler.BeginReceive(
buffer, // An array of type Byt for received data
0, // The zero-based position in the buffer
buffer.Length, // The number of bytes to receive
0,// Specifies send and receive behaviors
new AsyncCallback(ReceiveCallback),//An AsyncCallback delegate
state // Specifies infomation for receive operation
);
}
catch (Exception exc) { MessageBox.Show(exc.ToString()); }
}
public void ReceiveCallback(IAsyncResult ar)
{
String response = "ok";
try
{
// Retrieve the state object and the handler socket
// from the asynchronous state object.
StateObject state = (StateObject)ar.AsyncState;
Socket handler = state.workSocket;
// Read data from the client socket.
int bytesRead = handler.EndReceive(ar);
// Received message
string content = string.Empty;
if (bytesRead > 0)
{
// There might be more data, so store the data received so far.
state.sb.Append(Encoding.ASCII.GetString(
state.buffer, 0, bytesRead));
// Check for end-of-file tag. If it is not there, read
// more data.
content = state.sb.ToString();
if (content.IndexOf("<Client Quit>") > -1)
{
// All the data has been read from the client
label3.Text = content;
}
else {
// Not all data received. Get more.
handler.BeginReceive(state.buffer, 0,StateObject.BufferSize, 0,
new AsyncCallback(ReceiveCallback), state);
}
「オブジェクト参照がオブジェクトのインスタンスに設定されていません」そして、これは、サーバ側の関数の残りの部分である： 誤差がある問題は、このラインである私は信じて
//func for echo back to client
private void Send(Socket handler, String data)
{
// Convert the string data to byte data using ASCII encoding.
byte[] byteData = Encoding.ASCII.GetBytes(data);
// Begin sending the data to the remote device.
handler.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), handler);
}
public void SendCallback(IAsyncResult ar)
{
try
{
// A Socket which has sent the data to remote host
Socket handler = (Socket)ar.AsyncState;
// The number of bytes sent to the Socket
int bytesSend = handler.EndSend(ar);
label3.Text = "Sent {0} bytes to Client" + bytesSend;
}
catch (Exception exc) { MessageBox.Show(exc.ToString()); }
私はそれを試しても感謝しましたが、エラーは同じです。 – shh
詳細は次のとおりです。 System.NullReferenceException：オブジェクト参照がオブジェクトのインスタンスに設定されていません。 at philoV3.Form1.Send（ソケットハンドラ、文字列データ）C：\ Users \ sara \ documents \ visual studio 2015 \ Projects \ philoV3 \ philoV3 \ Form1.cs：行538 – shh