//通过WebClient下载网页的源码

        string url = "http://www.example.com";
        System.Net.WebClient client = new System.Net.WebClient();

        client.Encoding = System.Text.Encoding.UTF8;

        string strHtml = client.DownloadString(url);

using System;

using System.Text;

using System.IO;

using System.Net;

namespace SnapUtility

{

    public class ServerResourceHelper

    {

        /// <summary>

        /// 通过WebClient获取远程资源

        /// </summary>

        /// <param name="url"></param>

        /// <returns></returns>

        public static string GetByWebClient(string url)

        {

            string strReturn = null;

            WebClient client = new WebClient();

            //client.Headers.Add(HttpRequestHeader.Accept, @"text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8");

            //client.Headers.Add(HttpRequestHeader.Referer, null);

            //client.Headers.Add(HttpRequestHeader.UserAgent, @" Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.154 Safari/537.36");

            //client.Headers.Add(HttpRequestHeader.ContentType, "application/octet-stream");

            string strExtension = Path.GetExtension(url); //扩展名

            if (String.IsNullOrEmpty(strExtension))

            {

                Stream stream = client.OpenRead(url);

                StreamReader streamReader = new StreamReader(stream, Encoding.GetEncoding("utf-8"));

                strReturn = streamReader.ReadToEnd();

                streamReader.Close();

                stream.Close();

            }

            else

            {

                string path = "../WebSnap/DownLoad/";

                path = System.Web.HttpContext.Current.Server.MapPath(path);

                //自动创建文件夹

                if (!Directory.Exists(path))

                {

                    Directory.CreateDirectory(path);

                }

                path += DateTime.Now.ToString("hhmmss") + strExtension;

                client.DownloadFile(new Uri(url), path);

            }

            client.Dispose();

            return strReturn;

        }

        /// <summary>

        /// 通过WebRequest获取远程资源

        /// </summary>

        /// <param name="url"></param>

        /// <returns></returns>

        public static string GetByWebRequest(string url)

        {

            string strReturn = null;

            Uri uri = new Uri(url);

            WebRequest request = WebRequest.Create(uri);

            WebResponse response = request.GetResponse();

            Stream stream = response.GetResponseStream();

            string strExtension = Path.GetExtension(url); //扩展名

            if (String.IsNullOrEmpty(strExtension))

            {

                StreamReader streamReader = new StreamReader(stream, Encoding.GetEncoding("utf-8"));

                strReturn = streamReader.ReadToEnd();

                streamReader.Close();

                stream.Close();

                response.Close();

            }

            else

            {

                string fileName = DateTime.Now.ToString("hhmmss") + strExtension;

                long length = response.ContentLength;

                strReturn = SaveFile(ref stream, fileName, length);

            }

            return strReturn;

        }

        /// <summary>

        /// 通过WebRequest的Http特定实现获取远程资源

        /// </summary>

        /// <param name="url">远程地址</param>

        /// <returns></returns>

        public static string GetByHttpWebRequest(string url)

        {

            string strReturn = null;

            Uri uri = new Uri(url);

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();

            Stream stream = response.GetResponseStream();

            string strExtension = Path.GetExtension(url); //扩展名

            if (String.IsNullOrEmpty(strExtension))

            {

                StreamReader streamReader = new StreamReader(stream, System.Text.Encoding.GetEncoding("utf-8"));

                strReturn = streamReader.ReadToEnd();

                streamReader.Close();

                stream.Close();

                response.Close();

            }

            else

            {

                string fileName = DateTime.Now.ToString("hhmmss") + strExtension;

                long length = response.ContentLength;

                strReturn = SaveFile(ref stream, fileName, length);

            }

            return strReturn;

        }

        /// <summary>

        /// FileStream保存文件

        /// </summary>

        /// <param name="stream"></param>

        private static string SaveFile(ref Stream stream, string fileName, long length)

        {

            byte[] buffer = new byte[length];

            stream.Read(buffer, , buffer.Length);

            stream.Close();

            string path = AppDomain.CurrentDomain.BaseDirectory + "DownLoad\\" + fileName;

            FileStream fileStream = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write);

            fileStream.Write(buffer, , buffer.Length);

            fileStream.Flush();

            fileStream.Close();

            return path;

        }

        /// <summary>

        /// 保存图片

        /// </summary>

        /// <param name="stream"></param>

        private static string SavePicture(ref Stream stream, string fileName)

        {

            System.Drawing.Image image = System.Drawing.Image.FromStream(stream);

            stream.Close();

            string path = "../WebSnap/DownLoad/";

            path = System.Web.HttpContext.Current.Server.MapPath(path);

            //自动创建文件夹

            if (!Directory.Exists(path))

            {

                Directory.CreateDirectory(path);

            }

            path += fileName;

            image.Save(path, System.Drawing.Imaging.ImageFormat.Png);

            image.Dispose(); //释放资源

            return path;

        }

    }

}