C#同步异步socket通讯编程
以用socket通讯发送和接受坐标点对（x,y）为例：
C#异步socket通讯--服务器端
在异步socket服务端中，建立连接、接收数据、发送数据都要设置回调函数。在每次监听连接、接收和发送数据是都需要调用BeginXXX的过程。特别需要注意的是，在接收数据时，若要不停的监听数据，每次收到数据后要立刻调用BeginReceive函数（见代码中的ReadCallback函数）；每次接收的实际数据可能小于设置的缓冲区大小（数据包小于缓冲区长度时）。
View Code
public
class
Channel
{
//
Thread signal.
public
static
ManualResetEvent allDone
=
new
ManualResetEvent(
false
);
static
Channel instance
=
null
;
private
bool
isConnected;
private
byte
[] buf;
float
x, y;
Socket socket, listener;
public
static
Channel Instance()
{
if
(instance
==
null
)
{
instance
=
new
Channel();
}
return
instance;
}
private
Channel()
{
buf
=
new
byte
[
1024
];
isConnected
=
false
;
x
=
0
;
y
=
0
;
}
public
bool
startServer(
string
strIP,
int
portNum)
{
socket
=
new
Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//
初始化socket
listener
=
new
Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//
初始化socket
IPAddress[] ipAddr
=
Dns.GetHostAddresses(strIP);
IPAddress ip
=
ipAddr[
0
];
IPEndPoint hostEP
=
new
IPEndPoint(ip, portNum);
try
{
listener.Bind(hostEP);
listener.Listen(
100
);
//
Set the event to nonsignaled state.
allDone.Reset();
listener.BeginAccept(
new
AsyncCallback(AcceptCallback),listener);
//
Wait until a connection is made before continuing.
allDone.WaitOne();
}
catch
(System.Exception ex)
{
MessageBox.Show(ex.ToString());
return
false
;
}
return
true
;
}
public
void
AcceptCallback(IAsyncResult ar)
{
//
Signal the main thread to continue.
allDone.Set();
//
Get the socket that handles the client request.
listener
=
(Socket)ar.AsyncState;
socket
=
listener.EndAccept(ar);
//
读取客户端内容
Thread t
=
new
Thread(
new
ThreadStart(threadrecv));
t.Start();
socket.BeginReceive(buf,
0
,
1024
,
0
,
new
AsyncCallback(ReadCallback),
null
);
isConnected
=
true
;
}
private
void
threadrecv()
{
socket.BeginReceive(buf,
0
,
1024
,
0
,
new
AsyncCallback(ReadCallback), socket);
}
public
void
ReadCallback(IAsyncResult ar)
{
int
byteread
=
socket.EndReceive(ar);
x
=
BitConverter.ToSingle(buf,
12
);
y
=
BitConverter.ToSingle(buf,
16
);
socket.BeginReceive(buf,
0
,
1024
,
0
,
new
AsyncCallback(ReadCallback), socket);
}
private
void
SendCallback(IAsyncResult ar)
{
try
{
//
Retrieve the socket from the state object.
Socket handler
=
(Socket)ar.AsyncState;
//
Complete sending the data to the remote device.
int
bytesSent
=
handler.EndSend(ar);
}
catch
(Exception e)
{
MessageBox.Show(e.ToString());
}
}
public
bool
getPoint(
ref
float
x,
ref
float
y)
{
x
=
this
.x;
y
=
this
.y;
return
true
;
}
public
bool
close()
{
try
{
socket.Shutdown(SocketShutdown.Both);
socket.Close();
listener.Close();
}
catch
(System.Exception ex)
{
MessageBox.Show(ex.Message);
return
false
;
}
return
true
;
}
public
bool
sendPoint(
float
x,
float
y)
{
if
(isConnected
==
false
)
{
return
false
;
}
float
flag
=
0
;
byte
[] bf
=
BitConverter.GetBytes(flag);
byte
[] bx
=
BitConverter.GetBytes(x);
byte
[] by
=
BitConverter.GetBytes(y);
byte
[] buffer
=
new
byte
[
50
];
bf.CopyTo(buffer,
0
);
bx.CopyTo(buffer,
4
);
by.CopyTo(buffer,
8
);
bf.CopyTo(buffer,
12
);
bf.CopyTo(buffer,
16
);
socket.BeginSend(buffer,
0
,
20
,
0
,
new
AsyncCallback(SendCallback), socket);
return
true
;
}
}
C#同步socket通讯
同步通讯比较简单，见代码（服务器端与客户端代码差别不大）
View Code
public
class
Channel
{
static
Channel instance
=
null
;
private
bool
isConnected;
private
byte
[] buf;
private
NetworkStream ns;
Socket socket;
public
static
Channel Instance()
{
if
(instance
==
null
)
{
instance
=
new
Channel();
}
return
instance;
}
private
Channel()
{
socket
=
new
Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//
初始化socket
buf
=
new
byte
[
1024
];
isConnected
=
false
;
}
public
bool
connect(
string
strIP,
int
portNum,
int
readTimeOut)
{
IPAddress [] ipAddr
=
Dns.GetHostAddresses(strIP);
IPAddress ip
=
ipAddr[
0
];
IPEndPoint hostEP
=
new
IPEndPoint(ip,portNum);
isConnected
=
true
;
try
{
Socket s
=
new
Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//
初始化socket
s.Bind(hostEP);
s.Listen(
0
);
socket
=
s.Accept();
//
尝试连接 客户端时
//
socket=socket.Connect(hostEP);
}
catch
(Exception se)
{
MessageBox.Show(
"
连接错误
"
+
se.Message,
"
提示信息
"
,
MessageBoxButtons.RetryCancel,MessageBoxIcon.Information);
isConnected
=
false
;
return
false
;
}
ns
=
new
NetworkStream(socket);
if
(readTimeOut
<
0
)
readTimeOut
=
0
;
ns.ReadTimeout
=
readTimeOut;
return
isConnected;
}
public
bool
getPoint(
ref
float
x,
ref
float
y)
{
if
(isConnected
==
false
)
{
return
false
;
}
try
{
if
(ns.DataAvailable)
{
while
(ns.DataAvailable)
{
ns.Read(buf,
0
,
20
);
}
}
else
{
ns.Read(buf,
0
,
20
);
}
}
catch
(Exception ex)
{
MessageBox.Show(ex.Message);
return
false
;
}
x
=
BitConverter.ToSingle(buf,
12
);
y
=
BitConverter.ToSingle(buf,
16
);
return
true
;
}
public
bool
close()
{
try
{
if
(ns
!=
null
)
{
ns.Close();
}
if
(socket
!=
null
)
{
socket.Close();
}
}
catch
(System.Exception ex)
{
MessageBox.Show(ex.Message);
return
false
;
}
return
true
;
}
public
bool
sendPoint(
float
x,
float
y)
{
if
(isConnected
==
false
)
{
return
false
;
}
float
flag
=
0
;
byte
[] bf
=
BitConverter.GetBytes(flag);
byte
[] bx
=
BitConverter.GetBytes(x);
byte
[] by
=
BitConverter.GetBytes(y);
bf.CopyTo(buf,
0
);
bx.CopyTo(buf,
4
);
by.CopyTo(buf,
8
);
bf.CopyTo(buf,
12
);
bf.CopyTo(buf,
16
);
try
{
ns.Write(buf,
0
,
20
);
}
catch
(Exception ex)
{
MessageBox.Show(ex.Message);
return
false
;
}
ns.Flush();
return
true
;
}
}
总结：在实时性要求比较高的系统中，用异步通讯是较好的选择；同步通讯由于发送和接收都是阻塞调用的，当需要接收数据而端口没有数据过来的时候，需要等待较长的时间影响系统性能，用多线程的方法对数据进行接收和发送也许是一个不错的选择，有待试验（例如在连接建立的同时开一个线程处理接收数据的函数）。