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;
}
}