使用LINQ to XML查询XML [英] Querying XML with LINQ to XML

问题描述

大家好！

我的应用程序使用LINQ to XML XElement将消息跟踪到xml文件中.这是结果xml文件的示例:

Hi all!

My application traces messages into xml-file by using LINQ to XML XElement. Here is sample of result xml-file:

<xml version="1.0" encoding="utf-8"?>
<Messages>
  <Message>
    <timeStamp>10.12.2010 12:05:57</timeStamp>
    <Level>Error</Level>
    <PID>1256</PID>
    <traceMessage>Error happened </traceMessage>
  </Message>
  <Message>
    <timeStamp>10.12.2010 12:06:07</timeStamp>
    <Level>Info</Level>
    <PID>5168</PID>
    <traceMessage>This is just info message</traceMessage>
  </Message>
  <Message>
<Messages>

现在，我的任务是创建WPF应用程序，该应用程序读取该xml文件并显示消息.问题是，消息级别有所不同(错误，信息)，我需要创建一些仅显示所需消息的过滤器或查询.例如仅显示错误消息".我该怎么办?

还是有可能查询该格式，还是我必须稍微改变我的文件格式?请您帮忙.

希望你有我的主意:)

干杯

Now my task is to create WPF application which reads that xml file and shows messages. The problem is that message level varies (error, info.) and I need create some filter or query which shows only wanted messages. For example "show only Error messages". How do I do that?

Or is it even possible query that format or do I have to change little bit my file formation? I kindly ask your help.

I hope you got my idea :)

Cheers

推荐答案

如果您的traceMessage元素中始终带有错误词，那么如果包含错误，则可以基于字符串比较进行过滤，然后返回错误消息.

但是我建议您向消息元素"添加一个属性，例如显示一个类别，无论是错误还是信息.

喜欢

If your traceMessage Element have always Error word inside then you can filter based on string comparison if it contains Error then it''s Error message.

But I would suggest you to add one attribute to Message Element like to show a category whether it''s error or Info.

like

<Message Category="Error">
...
...
</Message>
<Message Category="Info">
...
...
</Message>

应用LINQ筛选数据将更加容易.

[更新]

啊！！感谢您更新raitu，我可以建议您执行可能对您有帮助的查询.

It will be easier to apply LINQ to filter data.

[Update]

Ah!! Thanks for updating raitu, I can suggest you following query that might help you.

var resultXML = from c in TraceMessage.Elements("Message")
                      where ((string)c.Element("traceMessage")).Contains("Error")
                      select new {
                                    Timestamp = (String)c.Element("timestamp"),
                                     Level = (string)c.Element("Level"),
                                     PID = (string)c.Element("PID"),
                                     traceMessage  = (string)c.Element("tracemessage") };

这篇关于使用LINQ to XML查询XML的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！