微信公众平台开发学习系列（二）：微信公众平台接收消息与发送消息

本篇主要介绍如何使用senparc来处理微信公众平台的接收消息与发送消息。

首先微信端会将用户的发送的信息以post请求发送到填写的url上，服务端代码如下：

1         [HttpPost]
2         public ActionResult Get(PostModel postModel)
3         {
4             var messageHandler = new CustomMessageHandler(Request.InputStream, postModel);
5
6             messageHandler.Execute();//执行微信处理过程
7
8             return Content(messageHandler.ResponseDocument.ToString());
9         }

新建一个CustomMessageHandler类和一个CustomMessageContext类，CustomMessageHandler类继承MessageHandler<CustomMessageContext>，CustomMessageContext类继承MessageContext<IRequestMessageBase,IResponseMessageBase>，CustomMessageContext类的方法此处不贴出，主要是实现CustomMessageHandler类的方法，代码如下：

 1         public CustomMessageHandler(Stream inputStream, PostModel postModel)
 2             : base(inputStream, postModel)
 3         {
 4
 5         }
 6
 7         public override IResponseMessageBase DefaultResponseMessage(IRequestMessageBase requestMessage)
 8         {
 9             var responseMessage = base.CreateResponseMessage<ResponseMessageText>(); //ResponseMessageText指返回文本信息
10             responseMessage.Content = "这条消息来自DefaultResponseMessage。"+requestMessage.MsgId;
11             return responseMessage;
12         }

返回信息的格式多种多样，如：ResponseMessageText，ResponseMessageNews，ResponseMessageImage等。接收信息的格式也分很多种，不同格式有不同的处理方法：OnTextRequest，OnImageRequest,OnEvent_ViewRequest等。如果没有重写相应方法，就默认执行DefaultResponseMessage方法。本篇重写2个方法作为简单的例子。

用户发送文本信息情况下的返回信息处理

1         public override IResponseMessageBase OnTextRequest(RequestMessageText requestMessage)
2         {
3             var responseMessage = base.CreateResponseMessage<ResponseMessageText>();
4             responseMessage.Content = "您的OpenID是：" + requestMessage.FromUserName
5                                     + "。\r\n您发送了文字信息：" + requestMessage.Content;
6             return responseMessage;
7         }

菜单点击事件情况下的返回信息处理

 1         public override IResponseMessageBase OnEvent_ClickRequest(RequestMessageEvent_Click requestMessage)
 2         {
 3             IResponseMessageBase reponseMessage = null;
 4             //菜单点击，需要跟创建菜单时的Key匹配
 5             switch (requestMessage.EventKey)
 6             {
 7                 case "OneClick":
 8                     {
 9                         var strongResponseMessage = CreateResponseMessage<ResponseMessageNews>();
10                         reponseMessage = strongResponseMessage;
11                         strongResponseMessage.Articles.Add(new Article()
12                         {
13                             Title = "您点击了菜单图文按钮",
14                             Description = "您点击图文链接按钮，这是一条图文信息。",
15                             PicUrl = "https://ss2.baidu.com/6ONYsjip0QIZ8tyhnq/it/u=3233073314,694013259&fm=58&s=39C718720E8EBE011B398BAC0300F024",
16                             Url = "http://www.baidu.com"
17                         });
18                     }
19                     break;
20                 case "SubClickRoot_Text":
21                     {
22                         var strongResponseMessage = CreateResponseMessage<ResponseMessageText>();
23                         reponseMessage = strongResponseMessage;
24                         strongResponseMessage.Content = "您点击了子菜单按钮。";
25                     }
26                     break;
27                 default:
28                     {
29                         var strongResponseMessage = CreateResponseMessage<ResponseMessageText>();
30                         strongResponseMessage.Content = "您点击了按钮，EventKey：" + requestMessage.EventKey;
31                         reponseMessage = strongResponseMessage;
32                     }
33                     break;
34             }
35
36             return reponseMessage;
37         }