根据要求，您可以按照this post 的建议在客户端执行以下操作，但您可能需要考虑将同步Send 部分更改为异步Send，如下所示：
clientSocket.BeginSend(bytes, 0, bytes.Length, SocketFlags.None, endSendCallback, clientSocket); //use async
您的回调可能如下所示：
private static void endSendCallback(IAsyncResult ar) {
try {
SocketError errorCode;
int result = clientSocket.EndSend(ar, out errorCode);
Console.WriteLine(errorCode == SocketError.Success ?
"Successful! The size of the message sent was :" + result.ToString() :
"Error with error code: " + errorCode.ToString() //you probably want to consider to resend if there is error code, but best practice is to handle the error one by one
);
} catch (Exception e) { //exception
Console.WriteLine("Unhandled EndSend Exception! " + e.ToString());
//do something like retry or just report that the sending fails
//But since this is an exception, it probably best NOT to retry
}
}
至于上述改动后完整的客户端代码如何：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;
namespace TcpClientConsoleApplication {
class Program {
const int PORT_NO = 2201;
const string SERVER_IP = "127.0.0.1";
static Socket clientSocket; //put here
static void Main(string[] args) {
//Similarly, start defining your client socket as soon as you start.
clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
loopConnect(3, 3); //for failure handling
string result = "";
do {
result = Console.ReadLine(); //you need to change this part
if (result.ToLower().Trim() != "exit") {
byte[] bytes = Encoding.ASCII.GetBytes(result); //Again, note that your data is actually of byte[], not string
//do something on bytes by using the reference such that you can type in HEX STRING but sending thing in bytes
clientSocket.BeginSend(bytes, 0, bytes.Length, SocketFlags.None, endSendCallback, clientSocket); //use async
//clientSocket.Send(bytes); use this for sync send
}
} while (result.ToLower().Trim() != "exit");
}
private static void endSendCallback(IAsyncResult ar) {
try {
SocketError errorCode;
int result = clientSocket.EndSend(ar, out errorCode);
Console.WriteLine(errorCode == SocketError.Success ?
"Successful! The size of the message sent was :" + result.ToString() :
"Error with error code: " + errorCode.ToString() //you probably want to consider to resend if there is error code, but best practice is to handle the error one by one
);
} catch (Exception e) { //exception
Console.WriteLine("Unhandled EndSend Exception! " + e.ToString());
//do something like retry or just report that the sending fails
//But since this is an exception, it probably best NOT to retry
}
}
static void loopConnect(int noOfRetry, int attemptPeriodInSeconds) {
int attempts = 0;
while (!clientSocket.Connected && attempts < noOfRetry) {
try {
++attempts;
IAsyncResult result = clientSocket.BeginConnect(IPAddress.Parse(SERVER_IP), PORT_NO, endConnectCallback, null);
result.AsyncWaitHandle.WaitOne(TimeSpan.FromSeconds(attemptPeriodInSeconds));
System.Threading.Thread.Sleep(attemptPeriodInSeconds * 1000);
} catch (Exception e) {
Console.WriteLine("Error: " + e.ToString());
}
}
if (!clientSocket.Connected) {
Console.WriteLine("Connection attempt is unsuccessful!");
return;
}
}
private const int BUFFER_SIZE = 4096;
private static byte[] buffer = new byte[BUFFER_SIZE]; //buffer size is limited to BUFFER_SIZE per message
private static void endConnectCallback(IAsyncResult ar) {
try {
clientSocket.EndConnect(ar);
if (clientSocket.Connected) {
clientSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(receiveCallback), clientSocket);
} else {
Console.WriteLine("End of connection attempt, fail to connect...");
}
} catch (Exception e) {
Console.WriteLine("End-connection attempt is unsuccessful! " + e.ToString());
}
}
const int MAX_RECEIVE_ATTEMPT = 10;
static int receiveAttempt = 0;
private static void receiveCallback(IAsyncResult result) {
System.Net.Sockets.Socket socket = null;
try {
socket = (System.Net.Sockets.Socket)result.AsyncState;
if (socket.Connected) {
int received = socket.EndReceive(result);
if (received > 0) {
receiveAttempt = 0;
byte[] data = new byte[received];
Buffer.BlockCopy(buffer, 0, data, 0, data.Length); //There are several way to do this according to https://stackoverflow.com/questions/5099604/any-faster-way-of-copying-arrays-in-c in general, System.Buffer.memcpyimpl is the fastest
//DO ANYTHING THAT YOU WANT WITH data, IT IS THE RECEIVED PACKET!
//Notice that your data is not string! It is actually byte[]
//For now I will just print it out
Console.WriteLine("Server: " + Encoding.UTF8.GetString(data));
socket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(receiveCallback), socket);
} else if (receiveAttempt < MAX_RECEIVE_ATTEMPT) { //not exceeding the max attempt, try again
++receiveAttempt;
socket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(receiveCallback), socket);
} else { //completely fails!
Console.WriteLine("receiveCallback is failed!");
receiveAttempt = 0;
clientSocket.Close();
}
}
} catch (Exception e) { // this exception will happen when "this" is be disposed...
Console.WriteLine("receiveCallback is failed! " + e.ToString());
}
}
}
}
关于上述代码如何工作的完整解释（注意第 7 点已更改，并为 async Send 添加了第 8 点）：
客户：
-
同样，将Socket 类放在类上下文而不是方法上下文中，并在启动程序时立即对其进行初始化
const int PORT_NO = 2201;
const string SERVER_IP = "127.0.0.1";
static Socket clientSocket; //put here
static void Main(string[] args) {
//Similarly, start defining your client socket as soon as you start.
clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//your other main routines
}
-
然后通过ASyncBeginConnect开始连接。我通常会更进一步 LoopConnect 只是为了这样的故障处理。
static void loopConnect(int noOfRetry, int attemptPeriodInSeconds) {
int attempts = 0;
while (!clientSocket.Connected && attempts < noOfRetry) {
try {
++attempts;
IAsyncResult result = clientSocket.BeginConnect(IPAddress.Parse(SERVER_IP), PORT_NO, endConnect, null);
result.AsyncWaitHandle.WaitOne(TimeSpan.FromSeconds(attemptPeriodInSeconds));
System.Threading.Thread.Sleep(attemptPeriodInSeconds * 1000);
} catch (Exception e) {
Console.WriteLine("Error: " + e.ToString());
}
}
if (!clientSocket.Connected) {
Console.WriteLine("Connection attempt is unsuccessful!");
return;
}
}
与您对服务器 BeginAccept 所做的操作类似的概念，您需要为您使用的 ASync BeginConnect 定义 endConnectCallback。但是这里不像服务器需要重新调用BeginAccept，一旦你连接上，你不需要做任何新的BeginConnect，因为你只需要连接一次。
-
你可能要声明buffer等。然后，在你连接之后，不要忘记下一个ASyncBeginReceive来处理消息检索部分（与服务器类似）
private const int BUFFER_SIZE = 4096;
private static byte[] buffer = new byte[BUFFER_SIZE]; //buffer size is limited to BUFFER_SIZE per message
private static void endConnectCallback(IAsyncResult ar) {
try {
clientSocket.EndConnect(ar);
if (clientSocket.Connected) {
clientSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(receiveCallback), clientSocket);
} else {
Console.WriteLine("End of connection attempt, fail to connect...");
}
} catch (Exception e) {
Console.WriteLine("End-connection attempt is unsuccessful! " + e.ToString());
}
}
当然，您需要定义您的receiveCallback，就像您为服务器所做的一样。是的，正如您所猜测的那样，它几乎与您为服务器所做的相同！
-
您可以对您的数据做任何您想做的事情。请注意，您收到的数据实际上是在byte[]，而不是string。所以你可以用它做任何事情。但是为了举例，我就用string来显示吧。
const int MAX_RECEIVE_ATTEMPT = 10;
static int receiveAttempt = 0;
private static void receiveCallback(IAsyncResult result) {
System.Net.Sockets.Socket socket = null;
try {
socket = (System.Net.Sockets.Socket)result.AsyncState;
if (socket.Connected) {
int received = socket.EndReceive(result);
if (received > 0) {
receiveAttempt = 0;
byte[] data = new byte[received];
Buffer.BlockCopy(buffer, 0, data, 0, data.Length); //copy the data from your buffer
//DO ANYTHING THAT YOU WANT WITH data, IT IS THE RECEIVED PACKET!
//Notice that your data is not string! It is actually byte[]
//For now I will just print it out
Console.WriteLine("Server: " + Encoding.UTF8.GetString(data));
socket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(receiveCallback), socket);
} else if (receiveAttempt < MAX_RECEIVE_ATTEMPT) { //not exceeding the max attempt, try again
++receiveAttempt;
socket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(receiveCallback), socket);
} else { //completely fails!
Console.WriteLine("receiveCallback is failed!");
receiveAttempt = 0;
clientSocket.Close();
}
}
} catch (Exception e) { // this exception will happen when "this" is be disposed...
Console.WriteLine("receiveCallback is failed! " + e.ToString());
}
}
-
下一个（在最后一个之前）——是的，同样，正如你已经猜到的，你只需要在你的主程序上做一些事情——假设你想用它来处理BeginSend 数据。因为你使用Console，但是你希望它以byte[]发送东西，所以你需要进行转换（参见linked post的服务器9中的解释）。
static void Main(string[] args) {
//Similarly, start defining your client socket as soon as you start.
clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
loopConnect(3, 3); //for failure handling
string result = "";
do {
result = Console.ReadLine(); //you need to change this part
if (result.ToLower().Trim() != "exit") {
byte[] bytes = Encoding.ASCII.GetBytes(result); //Again, note that your data is actually of byte[], not string
//do something on bytes by using the reference such that you can type in HEX STRING but sending thing in bytes
clientSocket.BeginSend(bytes, 0, bytes.Length, SocketFlags.None, endSendCallback, clientSocket); //use async
//clientSocket.Send(bytes); use this for sync send
}
} while (result.ToLower().Trim() != "exit");
}
-
最后，最后，你只需要声明异步EndSend回调函数就完成了！
private static void endSendCallback(IAsyncResult ar) {
try {
SocketError errorCode;
int result = clientSocket.EndSend(ar, out errorCode);
Console.WriteLine(errorCode == SocketError.Success ?
"Successful! The size of the message sent was :" + result.ToString() :
"Error with error code: " + errorCode.ToString() //you probably want to consider to resend if there is error code, but best practice is to handle the error one by one
);
} catch (Exception e) { //exception
Console.WriteLine("Unhandled EndSend Exception! " + e.ToString());
//do something like retry or just report that the sending fails
//But since this is an exception, it probably best NOT to retry
}
}