C#建立最简单的web服务，无需IIS

using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Diagnostics;
namespace TestWeb
{
    class RequestProcessor
    {
        public bool ParseRequestAndProcess(string[] RequestLines)//解析内容
        {
            for (int i = 0; i < RequestLines.Length; i++)
                System.Diagnostics.Trace.Write(RequestLines[i]);
            char[] sp = new Char[1] { ' ' };
            string[] strs = RequestLines[0].Split(sp);
            if (strs[0] == "GET")
            {
                Send(strs[1], 0, 0);
            }
            return false;
        }
        void Send(string filename, long start, long length)//发送文件（文件头和文件）
        {
            string strFileName = GetPathFileName(filename);
            FileStream fs = null;
            try
            {
                fs = new FileStream(strFileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
            }
            catch (IOException)// FileNotFoundException)
            {//不能将 e.Message,发给浏览器，否则会有安全隐患的
                SendHeadrAndStr("打开文件" + filename + "失败。");
                return;
            }
            if (length == 0)
                length = fs.Length - start;
            SendHeader("text/html", (fs.Length == length), start, length);
            sendContent(fs, start, length);
        }
        public void SendHeadrAndStr(String str)//直接将str的内容发给html
        {
            byte[] sendchars = Encoding.Default.GetBytes((str).ToCharArray());
            SendHeader("text/html", true, 0, sendchars.Length);
            SendStr(Encoding.Default, str);
        }
        private void SendHeader(string fileType, bool bAll, long start, long length)//发送文件头
        {
            try
            {
                Encoding coding = Encoding.Default;
                string strSend;
                string strState = (bAll) ? "HTTP/1.1 200 OK" : "HTTP/1.1 206 Partial Content";
                SendStr(coding, strState + "\r\n");
                SendStr(coding, "Date: \r\n");
                SendStr(coding, "Server: httpsrv/1.0\r\n");
                SendStr(coding, "MIME-Version: 1.0\r\n");
                SendStr(coding, "Content-Type: " + fileType + "\r\n");
                strSend = "Content-Length: " + length.ToString();
                SendStr(coding, strSend + "\r\n");
                //发送一个空行
                SendStr(coding, "\r\n");
            }
            catch (ArgumentException)//the request is WRONG
            {
            }
        }
        private void sendContent(FileStream fs, long start, long length)//发生文件内容
        {
            try
            {
                //报文头发送完毕，开始发送正文
                const int SOCKETWINDOWSIZE = 8192;
                long r = SOCKETWINDOWSIZE;
                int rd = 0;
                Byte[] senddatas = new Byte[SOCKETWINDOWSIZE];
                fs.Seek(start, SeekOrigin.Begin);
                do
                {
                    r = start + length - fs.Position;
                    //fs.BeginRead(s,s,s,s,d) 以后使用的版本，用以提高读取的效率                
                    if (r >= SOCKETWINDOWSIZE)
                        rd = fs.Read(senddatas, 0, SOCKETWINDOWSIZE);
                    else
                        rd = fs.Read(senddatas, 0, (int)r);
                    mSockSendData.Send(senddatas, 0, rd, SocketFlags.None);
                } while (fs.Position != start + length);
            }
            catch (SocketException e)
            {
                throw e;
            }
            catch (IOException e)
            {
                throw e;
            }
        }
        public Socket mSockSendData;//Notice: get from ClientSocketThread.s
        private string GetPathFileName(string filename)
        {
            const string strDefaultPage = "index.htm";
            const string strWWWRoot = "..\\..\\wwwroot\\";
            string strFileName = String.Copy(filename);
            if ("/" == strFileName)
                strFileName = strDefaultPage;
            return System.AppDomain.CurrentDomain.BaseDirectory + strWWWRoot + strFileName;
        }
        private void SendStr(Encoding coding, string strSend)//发送一个字符串
        {
            Byte[] sendchars = new Byte[512];
            sendchars = coding.GetBytes((strSend).ToCharArray());
            mSockSendData.Send(sendchars, 0, sendchars.Length, SocketFlags.None);
        }
    }
}

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
namespace TestWeb
{
    class ClientSocketThread
    {
        public TcpListener tcpl;//Notice: get from SrvMain.tcpl
        private static Encoding ASCII = Encoding.ASCII;
        public void HandleThread()
        {
            Thread currentThread = Thread.CurrentThread;
            try
            {
                Socket s = tcpl.AcceptSocket();
                RequestProcessor aRequestProcessor = new RequestProcessor(); //Notice:
                aRequestProcessor.mSockSendData = s;//Notice: so that the processor can work
                const int BUFFERSIZE = 4096;//that's enough???
                Byte[] readclientchar = new Byte[BUFFERSIZE];
                char[] sps = new Char[2] { '\r', '\n' };
                string[] RequestLines = new string[32];
                do
                {
                    //use BUFFERSIZE contral the receive data size to avoid the BufferOverflow attack
                    int rc = s.Receive(readclientchar, 0, BUFFERSIZE, SocketFlags.None);
                    string strReceive = ASCII.GetString(readclientchar, 0, rc);
                    RequestLines = strReceive.Split(sps);
                } while (aRequestProcessor.ParseRequestAndProcess(RequestLines));
                s.Close();
            }
            catch (SocketException)
            {
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Threading;
namespace TestWeb
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
              try
            {
                //启动监听程序                
                TcpListener tcpl;
                IPAddress LocalIP = Dns.Resolve("localhost").AddressList[0];
                tcpl = new TcpListener(LocalIP, 80); // listen on port 80
                tcpl.Start();
               // int ThreadID = 0;
                while (true)
                {
                    while (!tcpl.Pending())
                    {
                        Thread.Sleep(100);
                    }
                    //启动接受线程
                    ClientSocketThread myThreadHandler = new ClientSocketThread();
                    myThreadHandler.tcpl = tcpl;//Notice: dont forget do this
                    ThreadStart myThreadStart = new ThreadStart(myThreadHandler.HandleThread);
                    Thread myWorkerThread = new Thread(myThreadStart);      
                    myWorkerThread.Start();
                }
            }
            catch (SocketException )
            {
            }
            catch (FormatException)
            {
            }
            catch (Exception )
            {
            }
            //  Console.Read();
        }
    }
}