怎么样进行微信公众平台开发并发送文本消息.Net代码？

 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 EventKey { get; set; } 
 } 

protected void Page_Load(object sender, EventArgs e)
 {
  wxmessage wx = GetWxMessage();
  string res = "";

  if (!string.IsNullOrEmpty(wx.EventName) && wx.EventName.Trim() == "subscribe")
  {//刚关注时的时间，用于欢迎词
  string content = "";
  content = "/:rose欢迎北京永杰友信科技有限公司/:rose\n直接回复“你好”";
  res = sendTextMessage(wx, content);
  }
  else
  {
  if (wx.MsgType == "text" && wx.Content == "你好")
  {
   res = sendTextMessage(wx, "你好,欢迎使用北京永杰友信科技有限公司公共微信平台!");
  }
  else
  {
   res = sendTextMessage(wx, "你好,未能识别消息!");
  }
  }

  Response.Write(res);
 }

 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;
  }

  
  return wx;
 }

/// 
 /// 发送文字消息 
 /// 
 /// 获取的收发者信息 
 /// 内容 
 /// 
 private string sendTextMessage(wxmessage wx, string content)
 {
  string res = string.Format(@" ",
  wx.FromUserName, wx.ToUserName, DateTime.Now, content);
  return res;
 }