这几天，接手一个同事的代码，关于微信接口开发的，那一堆的 if，看得哥蛋痛了，这个毛病也是很多新手容易犯的，所以特地把这次重构写出来。

下面来我们看看这个代码的问题所在，if else 里面的代码块逻辑，不好改，使得它的重用性为 0，并且难以阅读。当然，如果 if 只有一两个，或者3个，这样写是问题不大的。

但是如果多了，这种代码便会让维护变得困难起来。

if (strMsgType == "text")

{

textContentClient = rootElement.SelectSingleNode("Content").InnerText;

strResult = SetMsgType_Text(strClientName, textContentClient, db, strServerName, Identity);

System.Diagnostics.Trace.WriteLine(strResult);

return Content(strResult);

}

else if (strMsgType == "event")

{

string eventType = rootElement.SelectSingleNode("Event").InnerText.ToLower();

if (eventType == "subscribe")

{

string keyCode = "";

if (rootElement.SelectSingleNode("EventKey") != null)

keyCode = rootElement.SelectSingleNode("EventKey").InnerText.ToLower();

strResult = FormatEventSubscribe(keyCode);

RecordReplyMessage();

return Content(strResult);

}

else if (eventType == "scan")

{

string keyCode = rootElement.SelectSingleNode("EventKey").InnerText.ToLower();

var outLetName = "欢迎关注";

var outletDB = ShoppingContext.CreateInstance(Identity);

var outLetModel = outletDB.Outlets.FirstOrDefault(o => o.SceneId == Int32.Parse(keyCode));

if (outLetModel != null)

outLetName += outLetModel.Name;

return Content(GetTextTemp(strClientName, strServerName, outLetName));

}

else if (eventType == "click")

{

string keyCode = rootElement.SelectSingleNode("EventKey").InnerText.ToLower();

strResult = FomatMenuMessage(keyCode);

return Content(strResult);

}

else if (eventType == "unsubscribe")

{

var subIds = db.ReplyRecords.Where(r => r.FromOpenId == this.ClientId.ToString() && r.EMessType == EEventType.Subscribe.ToString() && r.KeyWord != null).Select(o => o.KeyWord).ToArray();

var unSubIds = db.ReplyRecords.Where(r => r.FromOpenId == this.ClientId.ToString() && r.EMessType == EEventType.Unsubscribe.ToString() && r.KeyWord != null).Select(o => o.KeyWord).ToArray();

var SencesId = "";

foreach (var k in subIds)

{

if (!unSubIds.Contains(k))

{

this.ReplyModel.KeyWord = k;

break;

}

}

this.ReplyModel.EMessType = EEventType.Unsubscribe.ToString();

RecordReplyMessage();

}

}

else if (strMsgType.ToLower() == "location")

{

string strLocation_X = rootElement.SelectSingleNode("Location_X").InnerText;

string strLocation_Y = rootElement.SelectSingleNode("Location_Y").InnerText;

strResult = FormatOutLetLBS(double.Parse(strLocation_X), double.Parse(strLocation_Y), 10);

//strResult = FormatTextMessage(strLocation_X + "|" + strLocation_Y);

return Content(strResult);

}

else if (strMsgType.ToLower() == "image")

{

string strImgUrl = rootElement.SelectSingleNode("PicUrl").InnerText;

}

一种比较好的处理方法就是把语句块内的代码抽出来，写成函数，如下面所示：

public class MessageProcesser

{

public ReplyMessage Process(string xml)

{

var msg = PostMessage.FromXml(xml);

switch (msg.MsgType)

{

case Models.PostMessageType.Event:

var eventType = ((EventMessage)msg).Event;

switch (eventType)

{

case EventType.Click:

return ProcessClickEvent((ClickEvent)msg);

case EventType.Location:

return ProcessLocationEvent((LocationEvent)msg);

case EventType.Scan:

return ProcessScanEvent((ScanEvent)msg);

case EventType.Subscribe:

return ProcessSubscribeEvent((SubscribeEvent)msg);

case EventType.Unsubscribe:

return ProcessUnsubscribeEvent((UnsubscribeEvent)msg);

}

break;

case Models.PostMessageType.Image:

return ProcessImageMessage((ImageMessage)msg);

case Models.PostMessageType.Link:

return ProcessLinkMessage((LinkMessage)msg);

case Models.PostMessageType.Location:

return ProcessLocationMessage((LocationMessage)msg);

case Models.PostMessageType.Text:

return ProcessTextMessage((TextMessage)msg);

case Models.PostMessageType.Video:

return ProcessVideoMessage((VideoMessage)msg);

case Models.PostMessageType.Voice:

return ProcessVoiceMessage((VoiceMessage)msg);

}

return null;

}

protected virtual ReplyMessage ProcessClickEvent(ClickEvent msg)

{

return DefaultProcess(msg);

}

protected virtual ReplyMessage ProcessLocationEvent(LocationEvent msg)

{

return DefaultProcess(msg);

}

protected virtual ReplyMessage ProcessScanEvent(ScanEvent msg)

{

return DefaultProcess(msg);

}

protected virtual ReplyMessage ProcessSubscribeEvent(SubscribeEvent msg)

{

return DefaultProcess(msg);

}

protected virtual ReplyMessage ProcessUnsubscribeEvent(UnsubscribeEvent msg)

{

return DefaultProcess(msg);

}

protected virtual ReplyMessage ProcessImageMessage(ImageMessage msg)

{

return DefaultProcess(msg);

}

protected virtual ReplyMessage ProcessLinkMessage(LinkMessage msg)

{

return DefaultProcess(msg);

}

protected virtual ReplyMessage ProcessLocationMessage(LocationMessage msg)

{

return DefaultProcess(msg);

}

protected virtual ReplyMessage ProcessTextMessage(TextMessage msg)

{

return DefaultProcess(msg);

}

protected virtual ReplyMessage ProcessVideoMessage(VideoMessage msg)

{

return DefaultProcess(msg);

}

protected virtual ReplyMessage ProcessVoiceMessage(VoiceMessage msg)

{

return DefaultProcess(msg);

}

protected virtual ReplyMessage DefaultProcess(PostMessage msg)

{

var reply = new TextReply(msg);

if (msg.MsgType == PostMessageType.Event)

{

reply.Content = string.Format("{0} event is not processed.", ((EventMessage)msg).Event);

}

else

{

reply.Content = string.Format("{0} message is not processed.", msg.MsgType);

}

return reply;

}

}

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