微信開発者-アクティブリクエスト-準備作業-(1)get、postリクエストを送信し、ファイルをアップロード(C#)

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

/// <summary>
/// RequestHelper  
/// </summary>
public class RequestHelper
{
    // get 
    public static string sendGet(string url)
    {
        MemoryStream content = new MemoryStream();
        //  url Web 
        HttpWebRequest webRequest = WebRequest.Create(url) as HttpWebRequest;
        if (webRequest != null)
        {
            //  
            using (WebResponse response = webRequest.GetResponse())
            {
                using (Stream responseStream = response.GetResponseStream())
                {
                    using (StreamReader reader = new StreamReader(responseStream))
                    {
                        return reader.ReadToEnd();
                    }
                }
            }
        }
        return "";
    }
    // post 
    public static string sendPost(string url, string data)
    {
        HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(url);
        Encoding encoding = Encoding.UTF8;
        string param = data;
        //encoding.GetBytes(postData);
        byte[] bs = encoding.GetBytes(data); //Encoding.ASCII.GetBytes(param);
        string responseData = String.Empty;
        req.Method = "POST";
        req.ContentType = "application/x-www-form-urlencoded";
        req.ContentLength = bs.Length;
        using (Stream reqStream = req.GetRequestStream())
        {
            reqStream.Write(bs, 0, bs.Length);
            reqStream.Close();
        }
        using (HttpWebResponse response = (HttpWebResponse)req.GetResponse())
        {
            using (StreamReader reader = new StreamReader(response.GetResponseStream(), encoding))
            {
                responseData = reader.ReadToEnd().ToString();
                return responseData;
            }
        }
    }
    // 
    public static String uploadFile(String url, byte[] file, String contenttype, String filename)
    {
        byte[] buffer = file;
        string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
        // 
        WebRequest req = WebRequest.Create(url);
        req.Method = "POST";
        req.ContentType = "multipart/form-data; boundary=" + boundary;
        // 
        StringBuilder sb = new StringBuilder();
        sb.Append("--" + boundary + "\r
");
        sb.Append("Content-Disposition: form-data; name=\"media\"; filename=\"" + filename + "\"; filelength=\"" + buffer.Length + "\"");
        sb.Append("\r
");
        sb.Append("Content-Type: " + contenttype);
        sb.Append("\r
\r
");
        string head = sb.ToString();
        byte[] form_data = Encoding.UTF8.GetBytes(head);

        // 
        byte[] foot_data = Encoding.UTF8.GetBytes("\r
--" + boundary + "--\r
");

        //post 
        long length = form_data.Length + buffer.Length + foot_data.Length;

        req.ContentLength = length;

        Stream requestStream = req.GetRequestStream();
        // ， form_data > buffer > foot_data
        // 
        requestStream.Write(form_data, 0, form_data.Length);
        // 
        requestStream.Write(buffer, 0, buffer.Length);
        // 
        requestStream.Write(foot_data, 0, foot_data.Length);
        requestStream.Flush();
        requestStream.Close();
        // 
        WebResponse pos = req.GetResponse();
        StreamReader sr = new StreamReader(pos.GetResponseStream(), Encoding.UTF8);
        string result = sr.ReadToEnd().Trim();
        sr.Close();
        sr.Dispose();
        if (pos != null)
        {
            pos.Close();
            pos = null;
        }
        if (req != null)
        {
            req = null;
        }
        return result;
    }

}

HttpWebRequest webRequest = WebRequest.Create(url) as HttpWebRequest;

WebResponse response = webRequest.GetResponse()