微信公众平台开发之处理图片.Net代码解析

/// <summary>
  /// 下载保存多媒体文件,返回多媒体保存路径
  /// </summary>
  /// <param name="ACCESS_TOKEN"></param>
  /// <param name="MEDIA_ID"></param>
  /// <returns></returns>
  public string GetMultimedia(string ACCESS_TOKEN, string MEDIA_ID)
  {
    string file = string.Empty;
    string content = string.Empty;
    string strpath = string.Empty;
    string savepath = string.Empty;
    string stUrl = "http://file.api.weixin.qq.com/cgi-bin/media/get?access_token=" + ACCESS_TOKEN + "&media_id=" + MEDIA_ID;

    HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(stUrl);

    req.Method = "GET";
    using (WebResponse wr = req.GetResponse())
    {
      HttpWebResponse myResponse = (HttpWebResponse)req.GetResponse();

      strpath = myResponse.ResponseUri.ToString();
      WriteLog("接收类别://" + myResponse.ContentType);
      WebClient mywebclient = new WebClient();
      savepath = Server.MapPath("image") + "\\" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + (new Random()).Next().ToString().Substring(0, 4) + ".jpg";
      WriteLog("路径://" + savepath);
      try
      {
        mywebclient.DownloadFile(strpath, savepath);
        file = savepath;
      }
      catch (Exception ex)
      {
        savepath = ex.ToString();
      }

    }
    return file;
  }

 class wxmessage 
  { 
    public string FromUserName { get; set; } 
    public string ToUserName { get; set; } 
    public string MsgType { get; set; } 
    public string EventName { get; set; } 
    public string Content { get; set; }
    public string Recognition { get; set; }
    public string MediaId { get; set; }
    public string EventKey { get; set; } 
  }

private wxmessage GetWxMessage()
   {
     wxmessage wx = new wxmessage();
     StreamReader str = new StreamReader(Request.InputStream, System.Text.Encoding.UTF8);
     XmlDocument xml = new XmlDocument();
     xml.Load(str);
     wx.ToUserName = xml.SelectSingleNode("xml").SelectSingleNode("ToUserName").InnerText;
     wx.FromUserName = xml.SelectSingleNode("xml").SelectSingleNode("FromUserName").InnerText;
     wx.MsgType = xml.SelectSingleNode("xml").SelectSingleNode("MsgType").InnerText;
     if (wx.MsgType.Trim() == "text")
     {
       wx.Content = xml.SelectSingleNode("xml").SelectSingleNode("Content").InnerText;
     }
     if (wx.MsgType.Trim() == "event")
     {
       wx.EventName = xml.SelectSingleNode("xml").SelectSingleNode("Event").InnerText;
       wx.EventKey = xml.SelectSingleNode("xml").SelectSingleNode("EventKey").InnerText;
     }
     if (wx.MsgType.Trim() == "voice")
     {
       wx.Recognition = xml.SelectSingleNode("xml").SelectSingleNode("Recognition").InnerText;
     }
    if (wx.MsgType.Trim() == "image")
    {
      wx.MediaId = xml.SelectSingleNode("xml").SelectSingleNode("MediaId").InnerText;
    }
     
     return wx;
   }

/// <summary>
  /// 上传多媒体文件,返回 MediaId
  /// </summary>
  /// <param name="ACCESS_TOKEN"></param>
  /// <param name="Type"></param>
  /// <returns></returns>
  public string UploadMultimedia(string ACCESS_TOKEN, string Type)
  {
    string result = "";
    string wxurl = "http://file.api.weixin.qq.com/cgi-bin/media/upload?access_token=" + ACCESS_TOKEN + "&type=" + Type;
    string filepath = Server.MapPath("image") + "\\hemeng80.jpg";(本地服务器的地址)
    WriteLog("上传路径:" + filepath);
    WebClient myWebClient = new WebClient();
    myWebClient.Credentials = CredentialCache.DefaultCredentials;
    try
    {
      byte[] responseArray = myWebClient.UploadFile(wxurl, "POST", filepath);
      result = System.Text.Encoding.Default.GetString(responseArray, 0, responseArray.Length);
      WriteLog("上传result:" + result);
      UploadMM _mode = JsonHelper.ParseFromJson<UploadMM>(result);
      result = _mode.media_id;
    }
    catch (Exception ex)
    {
      result = "Error:" + ex.Message;
    }
    WriteLog("上传MediaId:" + result);
    return result;
  }

protected string sendPicTextMessage(Msg _mode, string MediaId)
  {
    string res = string.Format(@"<xml>
                      <ToUserName><![CDATA[{0}]]></ToUserName>
                      <FromUserName><![CDATA[{1}]]></FromUserName>
                      <CreateTime>{2}</CreateTime>
                      <MsgType><![CDATA[image]]></MsgType>
                      <Image>
                      <MediaId><![CDATA[{3}]]></MediaId>
                      </Image>
                  </xml> ",
      _mode.FromUserName, _mode.ToUserName, DateTime.Now, MediaId);

    return res;
  }