// 模拟 IE 6.0
WebClient wc = new WebClient( );
wc.Headers.Add ( "Accept", "image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, */*" );
wc.Headers.Add ( "Accept-Language", "zh-CN" );
wc.Headers.Add ( "User-Agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)" );
Stream s = wc.OpenRead (url);
StreamReader sr = new StreamReader(s, Encoding.UTF8 );
string result = sr.ReadToEnd ( );

updat t set b=b+1 where id=1;
select b from t where id=1;

update t set b=b-1 where id=1;
select b from t where id=1;

using Microsoft.Win32;

using System;
using System.Collections.Generic;
using Microsoft.Win32;

namespace  Register
{
    public class RegisterOperate
    {

        /**/
        /// <summary>
        /// 写入注册表
        /// </summary>
        /// <param name="strName"></param>
        public static void SetRegEditData(string strName, string strValue)
        {
            try
            {
                RegistryKey hklm = Registry.LocalMachine;
                RegistryKey software = hklm.OpenSubKey("SOFTWARE", true);
                RegistryKey aimdir = software.CreateSubKey("MySoftware");
                aimdir.SetValue(strName, strValue);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }

        }

        /**/
        /// <summary>
        /// 修改注册表项
        /// </summary>
        /// <param name="strName"></param>
        /// <param name="strValue"></param>
        public static void ModifyRegEditData(string strName, string strValue)
        {
            try
            {
                RegistryKey hklm = Registry.LocalMachine;
                RegistryKey software = hklm.OpenSubKey("SOFTWARE\\MySoftware", true);
                software.SetValue(strName, strValue);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }

        /**/
        /// <summary>
        /// 判断指定注册表项是否存在
        /// </summary>
        /// <param name="strName"></param>
        /// <returns></returns>
        public static bool IsExist(string strName)
        {
            try
            {
                bool exit = false;
                string[] subkeyNames;
                RegistryKey hkml = Registry.LocalMachine;
                RegistryKey software = hkml.OpenSubKey("SOFTWARE", true);
                RegistryKey aimdir = software.OpenSubKey("MySoftware", true);
                subkeyNames = aimdir.GetValueNames();
                foreach (string keyName in subkeyNames)
                {
                    if (keyName == strName)
                    {
                        exit = true;
                        return exit;
                    }
                }
                return exit;
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                return false;
            }
        }

    }
}

DateTime dtBeginTime = DateTime.Now;

// 测试程序

DateTime dtEndTime = DateTime.Now;

TimeSpan ts = dtEndTime.Subtract(dtBeginTime);

Console.WriteLine(ts.ToString());

System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();
sw.Start();

// 测试程序

sw.Stop();
Console.WriteLine(string.Format("{0}.{1}"), sw.Elapsed.Seconds, sw.Elapsed.Milliseconds);