C#中使用TCP通信
TCP通信需要通信双方都在线，所以需要先启动服务端进行监听，客户端才能获得连接，服务端代码：
static void Main(string[] args)
{
TcpClient client = null;
NetworkStream stream = null;
byte[] buffer = null;
string receiveString = null;
IPAddress localIP = IPAddress.Parse("127.0.0.1");
int localPort = 11000;
TcpListener listener = new TcpListener(localIP, localPort);//用本地IP和端口实例化Listener
listener.Start();//开始监听
while (true)
{
client = listener.AcceptTcpClient();//接受一个Client
buffer = new byte[client.ReceiveBufferSize];
stream = client.GetStream();//获取网络流
stream.Read(buffer, 0, buffer.Length);//读取网络流中的数据
stream.Close();//关闭流
client.Close();//关闭Client
receiveString = Encoding.Default.GetString(buffer).Trim('\0');//转换成字符串
Console.WriteLine(receiveString);
}
}
只有服务端开启监听后，客户端才能正确连接，所以服务端要一直开启监听，客户端每次发送数据，都要首先与服务端建立连接，连接建立完成后才进行数据发送。客户端代码：
static void Main(string[] args)
{
string sendString = null;//要发送的字符串
byte[] sendData = null;//要发送的字节数组
TcpClient client = null;//TcpClient实例
NetworkStream stream = null;//网络流
IPAddress remoteIP = IPAddress.Parse("127.0.0.1");//远程主机IP
int remotePort = 11000;//远程主机端口
while (true)//死循环
{
sendString = Console.ReadLine();//获取要发送的字符串
sendData = Encoding.Default.GetBytes(sendString);//获取要发送的字节数组
client = new TcpClient();//实例化TcpClient
try
{
client.Connect(remoteIP, remotePort);//连接远程主机
}
catch (System.Exception ex)
{
Console.WriteLine("连接超时，服务器没有响应！");//连接失败
Console.ReadKey();
return;
}
stream = client.GetStream();//获取网络流
stream.Write(sendData, 0, sendData.Length);//将数据写入网络流
stream.Close();//关闭网络流
client.Close();//关闭客户端
}
}
C#中使用UDP通信
UDP通信是无连接通信，客户端在发送数据前无需与服务器端建立连接，即使服务器端不在线也可以发送，但是不能保证服务器端可以收到数据。
服务器端代码：
static void Main(string[] args)
{
UdpClient client = null;
string receiveString = null;
byte[] receiveData = null;
//实例化一个远程端点，IP和端口可以随意指定，等调用client.Receive(ref remotePoint)时会将该端点改成真正发送端端点
IPEndPoint remotePoint = new IPEndPoint(IPAddress.Any, 0);
while (true)
{
client = new UdpClient(11000);
receiveData = client.Receive(ref remotePoint);//接收数据
receiveString = Encoding.Default.GetString(receiveData);
Console.WriteLine(receiveString);
client.Close();//关闭连接
}
}
客户端代码：
static void Main(string[] args)
{
string sendString = null;//要发送的字符串
byte[] sendData = null;//要发送的字节数组
UdpClient client = null;
IPAddress remoteIP = IPAddress.Parse("127.0.0.1");
int remotePort = 11000;
IPEndPoint remotePoint = new IPEndPoint(remoteIP, remotePort);//实例化一个远程端点
while (true)
{
sendString = Console.ReadLine();
sendData = Encoding.Default.GetBytes(sendString);
client = new UdpClient();
client.Send(sendData, sendData.Length, remotePoint);//将数据发送到远程端点
client.Close();//关闭连接
}
}
