网络上的两个程序通过一个双向的通信连接实现数据的交换，这个连接的一端称为一个socket。
以TCP协议为例：
客户端连接：
async private void SocketConnetct()
{
StreamSocke socket = new StreamSocket();

HostName hostName = new HostName("127.0.0");//ip
string serverPort = "12345";//端口port
await socket.ConnectAsync(hostName, serverPort);

using (DataWriter writer = new DataWriter(socket.OutputStream))
{
string content ="主机你好！我是客户端 ";
reqtb.Text = content;
writer.UnicodeEncoding = Windows.Storage.Streams.UnicodeEncoding.Utf8;
// 计算长度
uint len = writer.MeasureString(content);
// 写入长度
writer.WriteUInt32(len);
// 再写内容
writer.WriteString(content);

// 提交数据
await writer.StoreAsync();
}

DataReader DataReader reader = new DataReader(socket.InputStream); //实例化reader对象，并以StreamSocket的输入流为reader的来源
reader.InputStreamOptions = InputStreamOptions.Partial; //采用异步方式
reader.UnicodeEncoding = Windows.Storage.Streams.UnicodeEncoding.Utf8;
while (true) //循环读取消息
{
await reader.LoadAsync(sizeof(uint));
var ss = reader.ReadString(reader.UnconsumedBufferLength);
var len = reader.ReadUInt32();
// 读内容
await reader.LoadAsync(len);


string response = reader.ReadString(reader.UnconsumedBufferLength);

await Dispatcher.RunAsync(CoreDispatcherPriority.High, () =>
{
//更新UI
// restb.Text += response;

});
}

}
服务端侦听：
async private void CreatSocket()
{

StreamSocketListener listener = new StreamSocketListener();
listener.ConnectionReceived += Connection_Received;
await listener.BindServiceNameAsync("port");
}
private async void Connection_Received(StreamSocketListener sender, StreamSocketListenerConnectionReceivedEventArgs args)
{
// 获取用于通信的socket
StreamSocket socket = args.Socket;

DataReader DataReader reader = new DataReader(socket.InputStream); //实例化reader对象，并以StreamSocket的输入流为reader的来源
reader.InputStreamOptions = InputStreamOptions.Partial; //采用异步方式
reader.UnicodeEncoding = Windows.Storage.Streams.UnicodeEncoding.Utf8;
while (true) //循环读取消息
{
await reader.LoadAsync(sizeof(uint));
var ss = reader.ReadString(reader.UnconsumedBufferLength);
var len = reader.ReadUInt32();
// 读内容
await reader.LoadAsync(len);


string response = reader.ReadString(reader.UnconsumedBufferLength);

await Dispatcher.RunAsync(CoreDispatcherPriority.High, () =>
{
//更新UI
// restb.Text += response;

});
}


// 向客户端发送字符串：

using (DataWriter writer = new DataWriter(socket.OutputStream))
{
string content = "你好客户端！我是服务器。";
writer.UnicodeEncoding =Windows.Storage.Streams.UnicodeEncoding.Utf8;
// 计算长度
uint len = writer.MeasureString(content);
// 写入长度
writer.WriteUInt32(len);
// 再写内容
writer.WriteString(content);
// 提交数据
await writer.StoreAsync();
}
}

这样，一个简单的聊天程序就完成了；需要关闭连接时把socket，reader，writer全部dispos就行了。
UDP和TCP大同小异（DatagramSocket），不过UDP可以不用连接，直接发送。至于TCP和UDP的区别我这里就不详细讲了。
//注意！ uwp不允许在同一台机器上连接，所以必须要两台win10设备进行测试