新加企业微信企业客户标签回调事件

[xiaopotian1990]

新加企业微信企业客户标签回调事件 ，现版本没有该事件回调会抛异常
https://developer.work.weixin.qq.com/document/path/92130#%E4%BC%81%E4%B8%9A%E5%AE%A2%E6%88%B7%E6%A0%87%E7%AD%BE%E5%88%9B%E5%BB%BA%E4%BA%8B%E4%BB%B6

[JeffreySu]

@xiaopotian1990 非常感谢！
下述代码中 RequestMessageEvent_Change_External_Tag_Create 等构造函数需要有参数输入，否则编译会出错，麻烦检查一下：

switch (doc.Root.Element("ChangeType").Value.ToUpper())
{
    case "CREATE":
        requestMessage = new RequestMessageEvent_Change_External_Tag_Create();
        break;
    case "UPDATE":
        requestMessage = new RequestMessageEvent_Change_External_Tag_Update();
        break;
    case "DELETE":
        requestMessage = new RequestMessageEvent_Change_External_Tag_Delete();
        break;
    case "SHUFFLE":
        requestMessage = new RequestMessageEvent_Change_External_Tag_Shuffle();
        break;
    default://其他意外类型（也可以选择抛出异常）
        requestMessage = new RequestMessageEventBase();
        break;
}