public ActionResult DownloadApp()
{
     //获取客服端请求源
     string agent = Request.UserAgent;
     string[] keywords = { "Android", "iPhone", "iPod", "iPad", "Windows Phone", "MQQBrowser" };
     // CloudWave.Framework.Core.Logging.Logging4net.WriteInfo(agent);
     //排除 Windows 桌面系统           
     //if (!agent.Contains("Windows NT") || (agent.Contains("Windows NT") && agent.Contains("compatible; MSIE 9.0;")))
     var downloadurl = "";
     //判断是微信, 直接响应应用宝地址
     if (agent.ToLower().Contains("micromessenger"))
     {
         //获取配置信息
     }
     //安卓
     else if (agent.ToLower().Contains(keywords[0]))
     {
                
              
     }
     //苹果
     else if(agent.ToLower().Contains(keywords[1].ToLower())|| agent.ToLower().Contains(keywords[2].ToLower()) 
                || agent.ToLower().Contains(keywords[3].ToLower()))
     {
                
              
     }
       return Json(downloadurl);
}