一个HttpWebRequest工具类

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;

public class HttpRequestHelper
{
/// <summary>
/// 提交数据到某网页
/// </summary>
public static string PostToUrl(string requestUrl, byte[] byteArrayPost, Encoding encoding)
{
string stringResponse = "";
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(requestUrl);
webRequest.Method = "POST";
webRequest.ContentType = "application/x-www-form-urlencoded";
webRequest.ContentLength = byteArrayPost.Length;
webRequest.CookieContainer = new CookieContainer();
webRequest.Credentials = CredentialCache.DefaultCredentials;

Stream newStream = webRequest.GetRequestStream();
//写入参数
newStream.Write(byteArrayPost, 0, byteArrayPost.Length);
newStream.Close();

WebResponse webResponse = webRequest.GetResponse();

StreamReader responseStream = new StreamReader(webResponse.GetResponseStream(), encoding);
stringResponse = responseStream.ReadToEnd();
webResponse.Close();
responseStream.Close();
return stringResponse;
}

/// <summary>
/// 提交数据到某网页
/// </summary>
public static string GetToUrl(string requestUrl, Encoding encoding)
{

string stringResponse = "";
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(requestUrl);
webRequest.Method = "Get";
webRequest.ContentType = "application/x-www-form-urlencoded";

webRequest.CookieContainer = new CookieContainer();
webRequest.Credentials = CredentialCache.DefaultCredentials;
WebResponse webResponse = webRequest.GetResponse();

StreamReader responseStream = new StreamReader(webResponse.GetResponseStream(), encoding);
stringResponse = responseStream.ReadToEnd();
webResponse.Close();
responseStream.Close();
return stringResponse;
}
}