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;
    }
}