超级懒汉编写的基于.NET的微信SDK

一、前言

      特别不喜欢麻烦的一个人，最近碰到了微信开发。下载下来了一些其他人写的微信开发“框架”，但是被恶心到了，实现的太臃肿啦。

      最不喜欢的就是把微信返回的xml消息在组装成实体类，所以会比较臃肿，现在都提倡轻量级，所以有什么办法可以避免大量实体类的存在呢。

      当然，还有包装的比较繁杂，看完官方API后，再看"框架"，让人感觉一头雾水，不够清晰、明了。

二、我的实现思路

      我的微信SDK（不敢自称框架），最重要的实现2个目标：

      1.轻量级，就是要摒弃实体类，尽量少的申明Entity，减少SDK的体量；

      2.简单、明了，就是SDK类的划分和官方API保持一致，让人一看就懂你的用意。

      用户发送请是首先POST到微信服务器的，然后微信服务器在POST到我的服务器，这个接受的消息是xml,我猜测为什么是xml,而不是更轻量级的json，是为了更好的兼容性，毕竟xml更通用一些（说错了，请指出来）。而我们主动调用微信的一些API时，它返回的是json格式，我靠，要死啊，高大上啊。你们的副总裁张小龙不知道这事吗？好吧，这样其实也可以的。

       其实，调用微信的工作原理很简单，没有必要上来就框架什么的，我相信是个合格的程序员都能做出来。

       我们的服务器只需要一个GET,和一个POST就可以和微信通信了，从这一点来看，设计的还是比较人性化的，赞一个。GET用于接通微信服务的校验，验证；POST用于接收微信服务器过来的消息，然后将Response组装好返回即可。

三、上代码

       好了，废话不多说了。

       由于微信服务器Post给我们的是xml消息，返回的是json,所以需要互转。这样就存在3种类型的format,这也是大量的框架定义实体类导致框架不够轻量级的的原因之所在。

       实现第一个目标，我主要用到了.net Framework4.0的Dynamic特性，和一个将xml字符串自动转换成Dynamic Object的DynamicXml.cs类，还有一个将json字符串自动转换成Dynamic Object的DynamicJson.cs类。

       苦苦寻觅，终于让我找到了我想要的。

       1.以下是DynamicXml.cs类，文件头有原作者的版权信息。

/*--------------------------------------------------------------------------
 * https://www.captechconsulting.com/blog/kevin-hazzard/fluent-xml-parsing-using-cs-dynamic-type-part-1
 * 博客园网友 夜の魔王 友情借用此代码，用于微信开发。
 * http://www.cnblogs.com/deepleo/
*--------------------------------------------------------------------------*/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Dynamic;
using System.Xml.Linq;
using System.Collections;

public class DynamicXml : DynamicObject, IEnumerable
{
    private readonly List<XElement> _elements;

    public DynamicXml(string text)
    {
        var doc = XDocument.Parse(text);
        _elements = new List<XElement> { doc.Root };
    }

    protected DynamicXml(XElement element)
    {
        _elements = new List<XElement> { element };
    }

    protected DynamicXml(IEnumerable<XElement> elements)
    {
        _elements = new List<XElement>(elements);
    }

    public override bool TryGetMember(GetMemberBinder binder, out object result)
    {
        result = null;
        if (binder.Name == "Value")
            result = _elements[0].Value;
        else if (binder.Name == "Count")
            result = _elements.Count;
        else
        {
            var attr = _elements[0].Attribute(XName.Get(binder.Name));
            if (attr != null)
                result = attr;
            else
            {
                var items = _elements.Descendants(XName.Get(binder.Name));
                if (items == null || items.Count() == 0) return false;
                result = new DynamicXml(items);
            }
        }
        return true;
    }

    public override bool TryGetIndex(GetIndexBinder binder, object[] indexes, out object result)
    {
        int ndx = (int)indexes[0];
        result = new DynamicXml(_elements[ndx]);
        return true;
    }

    public IEnumerator GetEnumerator()
    {
        foreach (var element in _elements)
            yield return new DynamicXml(element);
    }
}

     这个代码我也没仔细看，反正能用，没出过差错。

      2.以下是DynamicJson.cs类，文件头有原作者的版权信息

/*--------------------------------------------------------------------------
* DynamicJson
* ver 1.2.0.0 (May. 21th, 2010)
*
* created and maintained by neuecc <ils@neue.cc>
* licensed under Microsoft Public License(Ms-PL)
* http://neue.cc/
* http://dynamicjson.codeplex.com/
 * 博客园网友 夜の魔王 友情借用此代码，用于微信开发。
 * http://www.cnblogs.com/deepleo/
*--------------------------------------------------------------------------*/
using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Dynamic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization.Json;
using System.Text;
using System.Xml;
using System.Xml.Linq;

namespace Codeplex.Data
{
    public class DynamicJson : DynamicObject
    {
        private enum JsonType
        {
            @string, number, boolean, @object, array, @null
        }

        // public static methods

        /// <summary>from JsonSring to DynamicJson</summary>
        public static dynamic Parse(string json)
        {
            return Parse(json, Encoding.Unicode);
        }

        /// <summary>from JsonSring to DynamicJson</summary>
        public static dynamic Parse(string json, Encoding encoding)
        {
            using (var reader = JsonReaderWriterFactory.CreateJsonReader(encoding.GetBytes(json), XmlDictionaryReaderQuotas.Max))
            {
                return ToValue(XElement.Load(reader));
            }
        }

        /// <summary>from JsonSringStream to DynamicJson</summary>
        public static dynamic Parse(Stream stream)
        {
            using (var reader = JsonReaderWriterFactory.CreateJsonReader(stream, XmlDictionaryReaderQuotas.Max))
            {
                return ToValue(XElement.Load(reader));
            }
        }

        /// <summary>from JsonSringStream to DynamicJson</summary>
        public static dynamic Parse(Stream stream, Encoding encoding)
        {
            using (var reader = JsonReaderWriterFactory.CreateJsonReader(stream, encoding, XmlDictionaryReaderQuotas.Max, _ => { }))
            {
                return ToValue(XElement.Load(reader));
            }
        }

        /// <summary>create JsonSring from primitive or IEnumerable or Object({public property name:property value})</summary>
        public static string Serialize(object obj)
        {
            return CreateJsonString(new XStreamingElement("root", CreateTypeAttr(GetJsonType(obj)), CreateJsonNode(obj)));
        }

        // private static methods

        private static dynamic ToValue(XElement element)
        {
            var type = (JsonType)Enum.Parse(typeof(JsonType), element.Attribute("type").Value);
            switch (type)
            {
                case JsonType.boolean:
                    return (bool)element;
                case JsonType.number:
                    return (double)element;
                case JsonType.@string:
                    return (string)element;
                case JsonType.@object:
                case JsonType.array:
                    return new DynamicJson(element, type);
                case JsonType.@null:
                default:
                    return null;
            }
        }

        private static JsonType GetJsonType(object obj)
        {
            if (obj == null) return JsonType.@null;

            switch (Type.GetTypeCode(obj.GetType()))
            {
                case TypeCode.Boolean:
                    return JsonType.boolean;
                case TypeCode.String:
                case TypeCode.Char:
                case TypeCode.DateTime:
                    return JsonType.@string;
                case TypeCode.Int16:
                case TypeCode.Int32:
                case TypeCode.Int64:
                case TypeCode.UInt16:
                case TypeCode.UInt32:
                case TypeCode.UInt64:
                case TypeCode.Single:
                case TypeCode.Double:
                case TypeCode.Decimal:
                case TypeCode.SByte:
                case TypeCode.Byte:
                    return JsonType.number;
                case TypeCode.Object:
                    return (obj is IEnumerable) ? JsonType.array : JsonType.@object;
                case TypeCode.DBNull:
                case TypeCode.Empty:
                default:
                    return JsonType.@null;
            }
        }

        private static XAttribute CreateTypeAttr(JsonType type)
        {
            return new XAttribute("type", type.ToString());
        }

        private static object CreateJsonNode(object obj)
        {
            var type = GetJsonType(obj);
            switch (type)
            {
                case JsonType.@string:
                case JsonType.number:
                    return obj;
                case JsonType.boolean:
                    return obj.ToString().ToLower();
                case JsonType.@object:
                    return CreateXObject(obj);
                case JsonType.array:
                    return CreateXArray(obj as IEnumerable);
                case JsonType.@null:
                default:
                    return null;
            }
        }

        private static IEnumerable<XStreamingElement> CreateXArray<T>(T obj) where T : IEnumerable
        {
            return obj.Cast<object>()
                .Select(o => new XStreamingElement("item", CreateTypeAttr(GetJsonType(o)), CreateJsonNode(o)));
        }

        private static IEnumerable<XStreamingElement> CreateXObject(object obj)
        {
            return obj.GetType()
                .GetProperties(BindingFlags.Public | BindingFlags.Instance)
                .Select(pi => new { Name = pi.Name, Value = pi.GetValue(obj, null) })
                .Select(a => new XStreamingElement(a.Name, CreateTypeAttr(GetJsonType(a.Value)), CreateJsonNode(a.Value)));
        }

        private static string CreateJsonString(XStreamingElement element)
        {
            using (var ms = new MemoryStream())
            using (var writer = JsonReaderWriterFactory.CreateJsonWriter(ms, Encoding.Unicode))
            {
                element.WriteTo(writer);
                writer.Flush();
                return Encoding.Unicode.GetString(ms.ToArray());
            }
        }

        // dynamic structure represents JavaScript Object/Array

        readonly XElement xml;
        readonly JsonType jsonType;

        /// <summary>create blank JSObject</summary>
        public DynamicJson()
        {
            xml = new XElement("root", CreateTypeAttr(JsonType.@object));
            jsonType = JsonType.@object;
        }

        private DynamicJson(XElement element, JsonType type)
        {
            Debug.Assert(type == JsonType.array || type == JsonType.@object);

            xml = element;
            jsonType = type;
        }

        public bool IsObject { get { return jsonType == JsonType.@object; } }

        public bool IsArray { get { return jsonType == JsonType.array; } }

        /// <summary>has property or not</summary>
        public bool IsDefined(string name)
        {
            return IsObject && (xml.Element(name) != null);
        }

        /// <summary>has property or not</summary>
        public bool IsDefined(int index)
        {
            return IsArray && (xml.Elements().ElementAtOrDefault(index) != null);
        }

        /// <summary>delete property</summary>
        public bool Delete(string name)
        {
            var elem = xml.Element(name);
            if (elem != null)
            {
                elem.Remove();
                return true;
            }
            else return false;
        }

        /// <summary>delete property</summary>
        public bool Delete(int index)
        {
            var elem = xml.Elements().ElementAtOrDefault(index);
            if (elem != null)
            {
                elem.Remove();
                return true;
            }
            else return false;
        }

        /// <summary>mapping to Array or Class by Public PropertyName</summary>
        public T Deserialize<T>()
        {
            return (T)Deserialize(typeof(T));
        }

        private object Deserialize(Type type)
        {
            return (IsArray) ? DeserializeArray(type) : DeserializeObject(type);
        }

        private dynamic DeserializeValue(XElement element, Type elementType)
        {
            var value = ToValue(element);
            if (value is DynamicJson)
            {
                value = ((DynamicJson)value).Deserialize(elementType);
            }
            return Convert.ChangeType(value, elementType);
        }

        private object DeserializeObject(Type targetType)
        {
            var result = Activator.CreateInstance(targetType);
            var dict = targetType.GetProperties(BindingFlags.Public | BindingFlags.Instance)
                .Where(p => p.CanWrite)
                .ToDictionary(pi => pi.Name, pi => pi);
            foreach (var item in xml.Elements())
            {
                PropertyInfo propertyInfo;
                if (!dict.TryGetValue(item.Name.LocalName, out propertyInfo)) continue;
                var value = DeserializeValue(item, propertyInfo.PropertyType);
                propertyInfo.SetValue(result, value, null);
            }
            return result;
        }

        private object DeserializeArray(Type targetType)
        {
            if (targetType.IsArray) // Foo[]
            {
                var elemType = targetType.GetElementType();
                dynamic array = Array.CreateInstance(elemType, xml.Elements().Count());
                var index = 0;
                foreach (var item in xml.Elements())
                {
                    array[index++] = DeserializeValue(item, elemType);
                }
                return array;
            }
            else // List<Foo>
            {
                var elemType = targetType.GetGenericArguments()[0];
                dynamic list = Activator.CreateInstance(targetType);
                foreach (var item in xml.Elements())
                {
                    list.Add(DeserializeValue(item, elemType));
                }
                return list;
            }
        }

        // Delete
        public override bool TryInvoke(InvokeBinder binder, object[] args, out object result)
        {
            result = (IsArray)
                ? Delete((int)args[0])
                : Delete((string)args[0]);
            return true;
        }

        // IsDefined, if has args then TryGetMember
        public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result)
        {
            if (args.Length > 0)
            {
                result = null;
                return false;
            }

            result = IsDefined(binder.Name);
            return true;
        }

        // Deserialize or foreach(IEnumerable)
        public override bool TryConvert(ConvertBinder binder, out object result)
        {
            if (binder.Type == typeof(IEnumerable) || binder.Type == typeof(object[]))
            {
                var ie = (IsArray)
                    ? xml.Elements().Select(x => ToValue(x))
                    : xml.Elements().Select(x => (dynamic)new KeyValuePair<string, object>(x.Name.LocalName, ToValue(x)));
                result = (binder.Type == typeof(object[])) ? ie.ToArray() : ie;
            }
            else
            {
                result = Deserialize(binder.Type);
            }
            return true;
        }

        private bool TryGet(XElement element, out object result)
        {
            if (element == null)
            {
                result = null;
                return false;
            }

            result = ToValue(element);
            return true;
        }

        public override bool TryGetIndex(GetIndexBinder binder, object[] indexes, out object result)
        {
            return (IsArray)
                ? TryGet(xml.Elements().ElementAtOrDefault((int)indexes[0]), out result)
                : TryGet(xml.Element((string)indexes[0]), out result);
        }

        public override bool TryGetMember(GetMemberBinder binder, out object result)
        {
            return (IsArray)
                ? TryGet(xml.Elements().ElementAtOrDefault(int.Parse(binder.Name)), out result)
                : TryGet(xml.Element(binder.Name), out result);
        }

        private bool TrySet(string name, object value)
        {
            var type = GetJsonType(value);
            var element = xml.Element(name);
            if (element == null)
            {
                xml.Add(new XElement(name, CreateTypeAttr(type), CreateJsonNode(value)));
            }
            else
            {
                element.Attribute("type").Value = type.ToString();
                element.ReplaceNodes(CreateJsonNode(value));
            }

            return true;
        }

        private bool TrySet(int index, object value)
        {
            var type = GetJsonType(value);
            var e = xml.Elements().ElementAtOrDefault(index);
            if (e == null)
            {
                xml.Add(new XElement("item", CreateTypeAttr(type), CreateJsonNode(value)));
            }
            else
            {
                e.Attribute("type").Value = type.ToString();
                e.ReplaceNodes(CreateJsonNode(value));
            }

            return true;
        }

        public override bool TrySetIndex(SetIndexBinder binder, object[] indexes, object value)
        {
            return (IsArray)
                ? TrySet((int)indexes[0], value)
                : TrySet((string)indexes[0], value);
        }

        public override bool TrySetMember(SetMemberBinder binder, object value)
        {
            return (IsArray)
                ? TrySet(int.Parse(binder.Name), value)
                : TrySet(binder.Name, value);
        }

        public override IEnumerable<string> GetDynamicMemberNames()
        {
            return (IsArray)
                ? xml.Elements().Select((x, i) => i.ToString())
                : xml.Elements().Select(x => x.Name.LocalName);
        }

        /// <summary>Serialize to JsonString</summary>
        public override string ToString()
        {
            // <foo type="null"></foo> is can't serialize. replace to <foo type="null" />
            foreach (var elem in xml.Descendants().Where(x => x.Attribute("type").Value == "null"))
            {
                elem.RemoveNodes();
            }
            return CreateJsonString(new XStreamingElement("root", CreateTypeAttr(jsonType), xml.Elements()));
        }
    }
}

      这个代码我也依旧没仔细看，反正也能用，没出过差错。

      这个最核心的拦路虎解决了，后面的事情就顺理成章的进行啦。

      3.基础支持API包装

/*--------------------------------------------------------------------------
* BasicAPI.cs
 *Auth:deepleo
* Date:2013.12.31
* Email:2586662969@qq.com
*--------------------------------------------------------------------------*/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Http;
using Codeplex.Data;
using System.IO;

namespace Deepleo.Weixin.SDK
{
    /// <summary>
    /// 对应微信API的 "基础支持"
    /// </summary>
    public class BasicAPI
    {
        /// <summary>
        /// 检查签名是否正确:
        /// http://mp.weixin.qq.com/wiki/index.php?title=%E6%8E%A5%E5%85%A5%E6%8C%87%E5%8D%97
        /// </summary>
        /// <param name="signature"></param>
        /// <param name="timestamp"></param>
        /// <param name="nonce"></param>
        /// <param name="token">AccessToken</param>
        /// <returns>
        /// true: check signature success
        /// false: check failed, 非微信官方调用!
        /// </returns>
        public static bool CheckSignature(string signature, string timestamp, string nonce, string token, out string ent)
        {
            var arr = new[] { token, timestamp, nonce }.OrderBy(z => z).ToArray();
            var arrString = string.Join("", arr);
            var sha1 = System.Security.Cryptography.SHA1.Create();
            var sha1Arr = sha1.ComputeHash(Encoding.UTF8.GetBytes(arrString));
            StringBuilder enText = new StringBuilder();
            foreach (var b in sha1Arr)
            {
                enText.AppendFormat("{0:x2}", b);
            }
            ent = enText.ToString();
            return signature == enText.ToString();
        }

        /// <summary>
        /// 获取AccessToken
        /// http://mp.weixin.qq.com/wiki/index.php?title=%E8%8E%B7%E5%8F%96access_token
        /// </summary>
        /// <param name="grant_type"></param>
        /// <param name="appid"></param>
        /// <param name="secrect"></param>
        /// <returns>access_toke</returns>
        public static dynamic GetAccessToken( string appid, string secrect)
        {
            var url = string.Format("https://api.weixin.qq.com/cgi-bin/token?grant_type={0}&appid={1}&secret={2}", "client_credential", appid, secrect);
            var client = new HttpClient();
            var result = client.GetAsync(url).Result;
            if (!result.IsSuccessStatusCode) return string.Empty;
            var token = DynamicJson.Parse(result.Content.ReadAsStringAsync().Result);
            return token;
        }

        /// <summary>
        /// 上传多媒体文件
        /// http://mp.weixin.qq.com/wiki/index.php?title=%E4%B8%8A%E4%BC%A0%E4%B8%8B%E8%BD%BD%E5%A4%9A%E5%AA%92%E4%BD%93%E6%96%87%E4%BB%B6
        /// 1.上传的媒体文件限制：
        ///图片（image) : 1MB，支持JPG格式
        ///语音（voice）：1MB，播放长度不超过60s，支持MP4格式
        ///视频（video）：10MB，支持MP4格式
        ///缩略图（thumb)：64KB，支持JPG格式
        ///2.媒体文件在后台保存时间为3天，即3天后media_id失效
        /// </summary>
        /// <param name="token"></param>
        /// <param name="type"></param>
        /// <param name="file"></param>
        /// <returns>media_id</returns>
        public static string UploadMedia(string token, string type, string file)
        {
            var url = string.Format("http://api.weixin.qq.com/cgi-bin/media/upload?access_token={0}&type={1}&filename={2}", token, type, Path.GetFileName(file));
            var client = new HttpClient();
            var result = client.PostAsync(url, new StreamContent(new FileStream(file, FileMode.Open, FileAccess.Read)));
            if (!result.Result.IsSuccessStatusCode) return string.Empty;
            var media = DynamicJson.Parse(result.Result.Content.ReadAsStringAsync().Result);
            return media.media_id;
        }


    }
}

      

       4.发送消息包装

/*--------------------------------------------------------------------------
* SendMessageAPI.cs
 *Auth:deepleo
* Date:2013.12.31
* Email:2586662969@qq.com
*--------------------------------------------------------------------------*/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Codeplex.Data;
using System.Net;
using System.Net.Http;

namespace Deepleo.Weixin.SDK
{
    /// <summary>
    /// 对应微信API的 "发送消息”
    /// </summary>
    public class SendMessageAPI
    {
        /// <summary>
        /// 被动回复消息
        /// </summary>
        /// <param name="message">微信服务器推送的消息</param>
        /// <param name="executor">用户自定义的消息执行者</param>
        /// <returns></returns>
        public static string Relay(WeixinMessage message, IWeixinExecutor executor)
        {
            return executor.Execute(message);
        }

        /// <summary>
        /// 主动发送客服消息
        /// http://mp.weixin.qq.com/wiki/index.php?title=%E5%8F%91%E9%80%81%E5%AE%A2%E6%9C%8D%E6%B6%88%E6%81%AF
        /// 当用户主动发消息给公众号的时候
        /// 开发者在一段时间内（目前为24小时）可以调用客服消息接口，在24小时内不限制发送次数。
        /// </summary>
        /// <param name="token"></param>
        /// <param name="msg">json格式的消息，具体格式请参考微信官方API</param>
        /// <returns></returns>
        public static bool Send(string token, string msg)
        {
            var client = new HttpClient();
            var task = client.PostAsync(string.Format("https://api.weixin.qq.com/cgi-bin/message/custom/send?access_token={0}", token), new StringContent(msg)).Result;
            return task.IsSuccessStatusCode;
        }
    }
}

       5.其他代码就不一一贴出来了。可以在文章最后自行下载完整代码查阅。

       6.处理与微信服务器通信的WeixinController.cs,WeixinExecutor.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.Mvc;
using System.Xml.Linq;
using Deepleo.Weixin.SDK;
using Deepleo.NewTon.Web.Services;
using System.Xml;
using Deepleo.NewTon.Framework.Services.Admin;
using Deepleo.Log;

namespace Deepleo.NewTon.Web.Controllers
{
    public class WeixinController : Controller
    {
        public WeixinController()
        {
        }

        /// <summary>
        /// 微信后台验证地址（使用Get），微信后台的“接口配置信息”的Url
        /// </summary>
        [HttpGet]
        [ActionName("Index")]
        public ActionResult Get(string signature, string timestamp, string nonce, string echostr)
        {
            var token = new SettingsService().Get().Token;
            if (string.IsNullOrEmpty(_token)) return Content("请先设置Token！");
            var ent = "";
            if (!BasicAPI.CheckSignature(signature, timestamp, nonce, _token, out ent))
            {
                new WeixinLogService().Create(new Framework.Entities.WeixinLog("get(failed)", string.Format("(get weixin)signature:{0},timestamp:{1},nonce:{2},echostr:{3},ent:{4},token:{5}",
                    signature, timestamp, nonce, echostr, ent, _token)));
                return Content("参数错误！");
            }
        
            return Content(echostr); //返回随机字符串则表示验证通过
        }

        /// <summary>
        /// 用户发送消息后，微信平台自动Post一个请求到这里，并等待响应XML。
        /// </summary>
        [HttpPost]
        [ActionName("Index")]
        public ActionResult Post(string signature, string timestamp, string nonce, string echostr)
        {
           
                WeixinMessage message = null;
                using (var streamReader = new StreamReader(Request.InputStream))
                {
                    message = AcceptMessageAPI.Parse(streamReader.ReadToEnd());
                }
              var  response = new WeixinExecutor().Execute(message);
            return new ContentResult
            {
                Content = response,
                ContentType = "text/xml",
                ContentEncoding = System.Text.UTF8Encoding.UTF8
            };
        }

    }
}

/*--------------------------------------------------------------------------
* WeixinExecutor.cs
 *Auth:deepleo
* Date:2013.12.31
* Email:2586662969@qq.com
*--------------------------------------------------------------------------*/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using Deepleo.Weixin.SDK;
using System.Text;
using System.Text.RegularExpressions;

namespace Deepleo.Weixin
{
    public class WeixinExecutor : IWeixinExecutor
    {
        public WeixinExecutor()
        {
        }

        public string Execute(WeixinMessage message)
        {
            var result = "";
            string openId = message.Body.FromUserName.Value;
            var myUserName = message.Body.ToUserName.Value;
            switch (message.Type)
            {
                case WeixinMessageType.Text:
                    string userMessage = message.Body.Content.Value;
                    result = RepayText(openId, myUserName, "欢迎使用");
                    break;
                case WeixinMessageType.Event:
                    string eventType = message.Body.Event.Value.ToLower();
                    string eventKey = message.Body.EventKey.Value;
                    switch (eventType)
                    {
                        case "subscribe":
                            result = RepayText(openId, myUserName, "欢迎订阅");
                            break;
                        case "unsubscribe":
                            result = RepayText(openId, myUserName, "欢迎再来");
                            break;
                        case "scan":
                            result = RepayText(openId, myUserName, "欢迎使用");
                            break;
                        case "location"://用户进入应用时记录用户地理位置
                            #region location
                            var lat = message.Body.Latitude.Value.ToString();
                            var lng = message.Body.Longitude.Value.ToString();
                            var pcn = message.Body.Precision.Value.ToString();

                            #endregion
                            break;
                        case "click":
                            switch (eventKey)//refer to： Recources/menu.json
                            {
                                case "myaccount":
                                    #region 我的账户
                                    result = RepayText(openId, myUserName, "我的账户.");
                                    #endregion
                                    break;
                                default:
                                    result = string.Format("<xml><ToUserName><![CDATA[{0}]]></ToUserName>" +
                                         "<FromUserName><![CDATA[{1}]]></FromUserName>" +
                                         "<CreateTime>{2}</CreateTime>" +
                                         "<MsgType><![CDATA[text]]></MsgType>" +
                                         "<Content><![CDATA[{3}]]></Content>" + "</xml>",
                                         openId, myUserName, DateTime.Now.ToBinary(), "没有响应菜单事件");
                                    break;
                            }
                            break;
                    }
                    break;
                default:
                    result = string.Format("<xml><ToUserName><![CDATA[{0}]]></ToUserName>" +
                                         "<FromUserName><![CDATA[{1}]]></FromUserName>" +
                                         "<CreateTime>{2}</CreateTime>" +
                                         "<MsgType><![CDATA[text]]></MsgType>" +
                                         "<Content><![CDATA[{3}]]></Content>" + "</xml>",
                                         openId, myUserName, DateTime.Now.ToBinary(), string.Format("未处理消息类型:{0}", message.Type));
                    break;
            }
            return result;
        }

        private string RepayText(string toUserName, string fromUserName, string content)
        {
            return string.Format("<xml><ToUserName><![CDATA[{0}]]></ToUserName>" +
                                                   "<FromUserName><![CDATA[{1}]]></FromUserName>" +
                                                   "<CreateTime>{2}</CreateTime>" +
                                                   "<MsgType><![CDATA[text]]></MsgType>" +
                                                   "<Content><![CDATA[{3}]]></Content>" + "</xml>",
                                                   toUserName, fromUserName, DateTime.Now.ToBinary(), content);
        }
        private string RepayNews(string toUserName, string fromUserName, List<WeixinNews> news)
        {
            var couponesBuilder = new StringBuilder();
            couponesBuilder.Append(string.Format("<xml><ToUserName><![CDATA[{0}]]></ToUserName>" +
            "<FromUserName><![CDATA[{1}]]></FromUserName>" +
            "<CreateTime>{2}</CreateTime>" +
            "<MsgType><![CDATA[news]]></MsgType>" +
            "<ArticleCount>{3}</ArticleCount><Articles>",
             toUserName, fromUserName,
             DateTime.Now.ToBinary(),
             news.Count
                ));
            foreach (var c in news)
            {
                couponesBuilder.Append(string.Format("<item><Title><![CDATA[{0}]]></Title>" +
                    "<Description><![CDATA[{1}]]></Description>" +
                    "<PicUrl><![CDATA[{2}]]></PicUrl>" +
                    "<Url><![CDATA[{3}]]></Url>" +
                    "</item>",
                   c.Title, c.Description, c.PicUrl, c.Url
                 ));
            }
            couponesBuilder.Append("</Articles></xml>");
            return couponesBuilder.ToString();
        }

    }
    public class WeixinNews
    {
        public string Title { set; get; }
        public string Description { set; get; }
        public string PicUrl { set; get; }
        public string Url { set; get; }
    }
}

Github在线浏览：https://github.com/night-king/weixinSDK

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开发者论坛：http://www.weixinsdk.net