C#中實現POST的方法很多，常用的是WebBrowser、WebClient、HttpWebRequest和HttpWebResponse。
1、WebBrowser基本是在DocumentCompleted中分析HtmlDocument ；
2、WebClient是對HttpWebRequest和HttpWebResponse的封裝，用起來更方便，但是靈活性還是不及HttpWebRequest和HttpWebResponse；
3、HttpWebRequest和HttpWebResponse更底層，靈活度更好，不過代碼更多，我做了一個簡單的封裝，將GET改成分段讀取，並加入代理、進度條和錯誤重試處理。代碼如下：
using System;
using System.IO;
using System.Net;
using System.Text;
namespace Van.Base
{
public class HttpHelper
{
#region 委托 事件
public delegate void dgtProgValueChanged(long Value);
/// <summary>
/// 進度改變事件
/// </summary>
public event dgtProgValueChanged OnProgValueChanged;
#endregion
#region 屬性
/// <summary>
/// 代理
/// </summary>
public WebProxy Proxy { get; set; }
/// <summary>
/// Cookie
/// </summary>
public CookieContainer UserCookie { get; set; }
/// <summary>
/// 重試次數
/// </summary>
public int IAfreshTime { get; set; }
/// <summary>
/// 錯誤次數
/// </summary>
public int IErrorTime { get; private set; }
long m_ProgValue = 0;
/// <summary>
/// 當前讀取字節
/// </summary>
public long ProgValue
{
get { return m_ProgValue; }
private set
{
m_ProgValue = value;
if (OnProgValueChanged != null)
{
OnProgValueChanged(value);
}
}
}
/// <summary>
/// 待讀取最大字節
/// </summary>
public long ProgMaximum { get; private set; }
#endregion
#region 方法
#region Get
/// <summary>
/// 獲取HTML
/// </summary>
/// <param name="URL">地址</param>
/// <param name="Accept">Accept請求頭</param>
/// <returns>Html代碼</returns>
public string GetHTML(string URL, string Accept)
{
return GetHTML(URL, Accept, System.Text.Encoding.UTF8);
}
/// <summary>
/// 獲取HTML
/// </summary>
/// <param name="URL">地址</param>
/// <param name="Accept">Accept請求頭</param>
/// <param name="encoding">字符編碼</param>
/// <returns>Html代碼</returns>
public string GetHTML(string URL, string Accept, Encoding encoding)
{
return GetHTML(URL, Accept, encoding, 1024);
}
/// <summary>
/// 獲取HTML
/// </summary>
/// <param name="URL">地址</param>
/// <param name="Accept">Accept請求頭</param>
/// <param name="encoding">字符編碼</param>
/// <param name="bufflen">數據包大小</param>
/// <returns>Html代碼</returns>
public string GetHTML(string URL, string Accept, Encoding encoding, int bufflen)
{
IErrorTime = 0;
return _GetHTML(URL, Accept, encoding, bufflen);
}
/// <summary>
/// 獲取HTML
/// </summary>
/// <param name="URL">地址</param>
/// <param name="Accept">Accept請求頭</param>
/// <param name="encoding">字符編碼</param>
/// <param name="bufflen">數據包大小</param>
/// <returns>Html代碼</returns>
private string _GetHTML(string URL, string Accept, Encoding encoding,int bufflen)
{
try
{
HttpWebRequest MyRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
MyRequest.Proxy = Proxy;
MyRequest.Accept = Accept;
if (UserCookie == null)
{
UserCookie = new CookieContainer();
}
MyRequest.CookieContainer = UserCookie;
HttpWebResponse MyResponse = (HttpWebResponse)MyRequest.GetResponse();
return _GetHTML(MyResponse, encoding, bufflen);
}
catch (Exception erro)
{
if (erro.Message.Contains("連接") && IAfreshTime - IErrorTime > 0)
{
IErrorTime++;
return _GetHTML(URL, Accept, encoding, bufflen);
}
throw;
}
}
/// <summary>
/// 獲取HTML
/// </summary>
/// <param name="MyResponse"></param>
/// <param name="encoding">字符編碼</param>
/// <param name="bufflen">數據包大小</param>
/// <returns></returns>
private string _GetHTML(HttpWebResponse MyResponse, Encoding encoding, int bufflen)
{
using (Stream MyStream = MyResponse.GetResponseStream())
{
ProgMaximum = MyResponse.ContentLength;
string result = null;
long totalDownloadedByte = 0;
byte[] by = new byte[bufflen];
int osize = MyStream.Read(by, 0, by.Length);
while (osize > 0)
{
totalDownloadedByte = osize + totalDownloadedByte;
result += encoding.GetString(by, 0, osize);
ProgValue = totalDownloadedByte;
osize = MyStream.Read(by, 0, by.Length);
}
MyStream.Close();
return result;
}
}
#endregion
#region GetImg
public System.Drawing.Bitmap Getimg(string URL, string Accept)
{
return _GetBit(URL, Accept);
}
/// <summary>
/// 獲取HTML
/// </summary>
/// <param name="URL">地址</param>
/// <param name="Accept">Accept請求頭</param>
/// <returns>Html代碼</returns>
private System.Drawing.Bitmap _GetBit(string URL, string Accept)
{
HttpWebRequest MyRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
MyRequest.Proxy = Proxy;
MyRequest.Accept = Accept;
if (UserCookie == null)
{
UserCookie = new CookieContainer();
}
MyRequest.CookieContainer = UserCookie;
HttpWebResponse MyResponse = (HttpWebResponse)MyRequest.GetResponse();
return _GetBit(MyResponse);
}
/// <summary>
/// 獲取圖像
/// </summary>
/// <param name="MyResponse"></param>
/// <returns></returns>
private System.Drawing.Bitmap _GetBit(HttpWebResponse MyResponse)
{
using (Stream MyStream = MyResponse.GetResponseStream())
{
return new System.Drawing.Bitmap(MyStream);
}
}
#endregion
#region Post
/// <summary>
/// 回發(字符編碼默認UTF-8)
/// </summary>
/// <param name="URL">回發地址</param>
/// <param name="PostData">參數</param>
/// <returns>Html代碼</returns>
public string PostPage(string URL, string PostData)
{
return PostPage(URL, PostData, System.Text.Encoding.UTF8);
}
/// <summary>
/// 回發
/// </summary>
/// <param name="URL">回發地址</param>
/// <param name="PostData">參數</param>
/// <param name="encoding">字符編碼</param>
/// <returns>Html代碼</returns>
public string PostPage(string URL, string PostData, Encoding encoding)
{
return PostPage(URL, PostData, encoding, null);
}
/// <summary>
/// 回發
/// </summary>
/// <param name="URL">回發地址</param>
/// <param name="PostData">參數</param>
/// <param name="encoding">字符編碼</param>
/// <returns>Html代碼</returns>
public string PostPage(string URL, string PostData, Encoding encoding, string ContentType)
{
IErrorTime = 0;
return _PostPage(URL, PostData, encoding, ContentType);
}
/// <summary>
/// 回發
/// </summary>
/// <param name="URL">回發地址</param>
/// <param name="PostData">參數</param>
/// <param name="encoding">字符編碼</param>
/// <returns>Html代碼</returns>
private string _PostPage(string URL, string PostData, Encoding encoding,string ContentType)
{
try
{
if (ContentType==null)
{
ContentType = "application/x-www-form-urlencoded";
}
HttpWebRequest MyRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
MyRequest.Proxy = Proxy;
if (UserCookie == null)
{
UserCookie = new CookieContainer();
}
MyRequest.CookieContainer = UserCookie;
MyRequest.Method = "POST";
MyRequest.ContentType = ContentType;
byte[] b = encoding.GetBytes(PostData);
MyRequest.ContentLength = b.Length;
using (System.IO.Stream sw = MyRequest.GetRequestStream())
{
try
{
sw.Write(b, 0, b.Length);
}
catch
{
}
}
HttpWebResponse MyResponse = (HttpWebResponse)MyRequest.GetResponse();
return _GetHTML(MyResponse, encoding, 1024);
}
catch (Exception erro)
{
if (erro.Message.Contains("連接") && IAfreshTime - IErrorTime > 0)
{
IErrorTime++;
return _PostPage(URL, PostData, encoding, ContentType);
}
throw;
}
}
#endregion
#endregion
}
}
調用便很方便了，如下：
string strProxyAdd = "www.Proxyxxxx.com", UserName = "XXXX",PassWord = "XXX";
int port = 8080;
HttpHelper http = new HttpHelper();
http.Proxy = new WebProxy();//設置代理
this.http.Proxy.Address = new Uri(string.Format("http://{0}:{1}", strProxyAdd,port));//設置代理服務器地址和端口
this.http.Proxy.Credentials = new NetworkCredential(UserName, PassWord);//設置代理用戶名密碼
//http.Proxy = null;//清空代理
var strPHtml = http.PostPage("www.xxxx.com", "User=ABCD&Pwd=DEF");//向www.xxxx.com POST數據User=ABCD&Pwd=DEF
var strHtml = http.GetHTML("www.xxxx.com", "*/*", Encoding.UTF8, 20480);//從www.xxxx.com獲取HTML數據，並用UTF8進行編碼
由於Cookie在一個實例中是共用的，在一些場景下可以先POST登錄後再GET需要登錄才能進入的頁面信息。
作者 二槓
