linq-to-xml的问题

Question

我希望linq将我的xml保存在csv中，但我没有问题。

这里有这个括号，因为如果没有它，代码就不会显示(为什么？)

<results>
    <Countries country="Albania">
        <Regions region="Centralna Albania">
            <Provinces province="Durres i okolice">
                <Cities city="Durres" cityCode="2B66E0ACFAEF78734E3AF1194BFA6F8DEC4C5760">
                    <IndividualFlagsWithForObjects Status="1" />
                    <IndividualFlagsWithForObjects  Status="0" />
                    <IndividualFlagsWithForObjects magazyn="2" />
                </Cities>
            </Provinces>
        </Regions>
    </Countries>
    <Countries country="Albania">
        <Regions region="Centralna Albania">
            <Provinces province="Durres i okolice">
                <Cities city="Durres" cityCode="2B66E0ACFAEF78734E3AF1194BFA6F8DEC4C5760">
                    <IndividualFlagsWithForObjects storage="0" Status="1" /> 
                    <IndividualFlagsWithForObjects storage="1" Status="0" /> 
                    <IndividualFlagsWithForObjects storage="2" Status="1" /> 
                </Cities>
            </Provinces>
        </Regions>
    </Countries>
</results>

我必须指出一件重要的事情:父节点是，但是当我使用它的结果(“loaded.Descendants”)时，它没有给我任何东西。

XDocument loaded = XDocument.Load(@"c:\citiesxml.xml");

// create a writer and open the file
TextWriter tw = new StreamWriter("c:\\XmltoCSV.txt");

// Query the data and write out a subset of contacts
var contacts = (from c in loaded.Descendants("Countries")
    select new
    {
        Country = (string)c.Attribute("ountry").Value,
        Region = (string)c.Element("Regions").Attribute("region").Value,
        Province= c.Element("Regions").Element("Provinces").Attribute("prowincja").Value,
        City= c.Element("Regions").Element("Provinces").Element("Cities").Attribute("city").Value,
        Kod = c.Element("Regions").Element("Provinces").Element("Cities").Attribute("cityCode").Value,
        IndywidualnaFlagaStatus = c.Element("Regions").Element("Provinces").Element("Cities").Element("IndividualFlagsWithForObjects").Attribute("Status"),
        IndywidualnaFlagaWartosc = c.Element("Regions").Element("Provinces").Element("Cities").Element("IndividualFlagsWithForObjects").Attribute("storage")
    }).ToList();

最后一个问题：

 IndywidualnaFlagaWartosc = c.Element("Regions").Element("Provinces").Element("Cities").Element("IndividualFlagsWithForObjects").Attribute("storage")

给了我：

IndywidualnaFlagaWartosc = {storage="0"} (I see this while debugging)

Answer 1

var contacts = (from c in loaded.Descendants("Countries")
                        select new
                        {
                            Country = (string)c.Attribute("Country").Value,
                            Region = (string)c.Element("Regions").Attribute("region").Value,
                            Province = (string)c.Element("Regions").Element("Provinces").Attribute("province").Value,
                            City = (string)c.Element("Regions").Element("Provinces").Element("Cities").Attribute("city").Value,
                            Hotel = (string)c.Element("Hotels").Attribute("hotel").Value
                        }).ToList();

酒店不在您的xml anywhere中，因此需要进行调整。我通常建议你拉取每个项目一次并检查是否为空，而不是像我在这里所做的那样拉取区域3次。

Answer 2

您的元素名称与您的xml片段不匹配(片段中的所有元素都是单数，而在linq查询中它们是复数(countries - country、regions - region等)。

 var contacts = (from c in loaded.Descendants("Countries")
                           select new
                           {
                               Country = c.Element("Countries").Value,
                               Region = c.Element("Regions").Value,
                               Province= c.Element("Provinces").Value,
                               City = c.Element("Cities").Value,
                               Hotel = c.Element("Hotels").Value
                           }).ToList();

Answer 3

您请求的元素是对象，而不是它的值。你的代码应该是：

var contacts = (from c in loaded.Descendants("Countries")
               select new
               {
                   Country = c.Element("Country").Value,
                   Region = c.Element("region").Value,
                   Province= c.Element("province").Value,
                   City = c.Element("city").Value,
                   Hotel = c.Element("hotel").Value
               }).ToList();

但是如果我看一下您的XML，我不确定这是否也会给出任何结果。我猜这应该会给你想要的结果：

var contacts = (from c in loaded.Descendants("Countries")
               select new
               {
                   Country = c.Attribute("country").Value,
                   Region = c.Descendants("Regions").FirstOrDefault().Attribute("region")Value,
                   Province= c.Descendants("Provinces").FirstOrDefault().Attribute("province").Value,
                   City = c.Descendants("Cities").FirstOrDefault().Attribute("city").Value,
                   Hotel = c.Descendants("Hotels").FirstOrDefault().Attribute("hotel").Value
               }).ToList();

请注意，此代码非常脆弱，因为如果缺少一个分面元素，就会发生异常。你应该对自己进行一些微调，以获得你想要的结果。