微信公众平台开发：请求消息去重

messageHandler.OmitRepeatedMessage = true;//启用消息去重功能

/// <summary>
 /// 最简化的处理流程（不加密）
 /// </summary>
 [HttpPost]
 [ActionName("MiniPost")]
 public ActionResult MiniPost(string signature, string timestamp, string nonce, string echostr)
 {
     if (!CheckSignature.Check(signature, timestamp, nonce, Token))
     {
         return new WeixinResult("参数错误！");//v0.8+
     }
 
     var messageHandler = new CustomMessageHandler(Request.InputStream, null, 10);
 
     messageHandler.OmitRepeatedMessage = true;//启用消息去重功能
 
     messageHandler.Execute();//执行微信处理过程
 
     return new FixWeixinBugWeixinResult(messageHandler);
 }

public virtual void OnExecuting()
{
    if (OmitRepeatedMessage && CurrentMessageContext.RequestMessages.Count > 1)
    {
        var lastMessage = CurrentMessageContext.RequestMessages[CurrentMessageContext.RequestMessages.Count - 2];
        if (lastMessage.MsgId != 0 && lastMessage.MsgId == RequestMessage.MsgId)
        {
            CancelExcute = true;//重复消息，取消执行
        }
    }
}