标签: linq-to-xml

我有一个像这样的xml结构:

<Items>
    <Configuration>
        <ConfigurationSetting>Setting1</ConfigurationSetting>
        <ConfigurationSetting>Setting2</ConfigurationSetting>
    </Configuration>
    <MetaData>
    ...
    </MetaData>
    <Group>
        <GroupType>MyType1</GroupType>
        <GroupType>MyType2</GroupType>
    </Group>
    <Group>  <--- Looking for this Element
        <Reference>MyReference1</Reference>
        <Reference>MyReference2</Reference>
    </Group>
    <Group>
        <GroupType>MyType3</GroupType>
        <GroupType>MyType4</GroupType>
    </Group>
</Items>

我想写一个Linq查询,返回包含子元素"引用"的第一个"组"元素.

谢谢你的帮助.

这是我将得到的回应:

<?xml version="1.0" encoding="utf-8"?>
<rsp stat="ok">
        <image_hash>cxmHM</image_hash>
        <delete_hash>NNy6VNpiAA</delete_hash>
        <original_image>http://imgur.com/cxmHM.png</original_image>
        <large_thumbnail>http://imgur.com/cxmHMl.png</large_thumbnail>
        <small_thumbnail>http://imgur.com/cxmHMl.png</small_thumbnail>
        <imgur_page>http://imgur.com/cxmHM</imgur_page>
        <delete_page>http://imgur.com/delete/NNy6VNpiAA</delete_page>
</rsp>

如何提取每个标签的值？

XDocument response = new XDocument(w.UploadValues("http://imgur.com/api/upload.xml", values));
string originalImage = 'do the extraction here';
string imgurPage = 'the same';
UploadedImage image = new UploadedImage();

我是Linq的新手请指导我一些基本的事情.

在阅读Linq的一些文章.一些authers从Linq查询中填充var中的数据,一些填充自定义类型对象的列表,一些填充IEnumerable中的数据,一些填充IQuryable中的数据.我无法得到这些4中的不同之处以及应该在哪种情况下使用哪一个.

我想使用Linq to SQL.我该怎么用？

如何从此Feed中获取"入口"节点

http://www.google.com/alerts/feeds/14392773026536511983/5526937985735563348

我试过linq到xml,但我认为因为代码后面的条目标签的现有属性不起作用.

string url = "http://www.google.com/alerts/feeds/14392773026536511983/5526937985735563348";

WebClient c = new WebClient();

string xml = ASCIIEncoding.Default.GetString(c.DownloadData(url));

XDocument doc = XDocument.Parse(xml);

var entries = doc.Descendants("entry");

提前致谢,

我是一个LINQ to XML的新手,我有这个代码可以工作(大部分时间):

private long processFile(StreamWriter oWriter, string inFileName)
    {
        XDocument xmlDoc = XDocument.Load(inFileName);
        List<DocMetaData> docList =
            (from d in xmlDoc.Descendants("DOCUMENT")
             select new DocMetaData
             {
                 Folder = d.Element("FOLDER").Attribute("name").Value
                 ,
                 File = d.Element("FILE").Attribute("filename").Value
                 ,
                 Comment = d.Elements("INDEX")
                    .Where(i => i.Attribute("name").Value == "Comment(idmComment)")
                    .First()
                    .Attribute("value").Value
                 ,
                 Title = d.Elements("INDEX")
                    .Where(i => i.Attribute("name").Value == "Title(idmName)")
                    .First()
                    .Attribute("value").Value
                 ,
                 DocClass = d.Elements("INDEX")
                    .Where(i => i.Attribute("name").Value == "Document Class(idmDocType)")
                    .First()
                    .Attribute("value").Value
             }
            ).ToList<DocMetaData>();
        OutputListToFile(oWriter, docList);
        return docList.LongCount();
    }

这在第117行(选择表达式)上失败:

    System.NullReferenceException: Object reference not set to …

我想用Linq读取一个xml文件.这个xml文件由1个头和N个子元素组成,如下所示:

<rootNode>
         <header>
            <company name="Dexter Corp." />
         </header>
         <elements>
           <element>one</element>
           <element>eleven</element>
           <element>three</element>
           <element>four</element>
           <element>five</element>
           <element>three</element>
           <element>two</element>
           <element>two</element>
         </elements>
</rootNode>

我想检索一个值的元素(例如:2).只有当我检索元素时,才会获得标题元素.

今天,我喜欢这样:

        string xmlFilePath = @"C:\numbers.xml";
        XDocument doc = XDocument.Load(xmlFilePath);

        var header = doc.Descendants().Elements("header");
        var elements = doc.Descendants()
            .Elements("elements")
                .Elements("element")
                .Where(el => el.Value == "two");

        // I get this values even if there is no 'elements'
        string companyName = header.Descendants("company").Attributes("name").Single().Value;
        string serialNumber = header.Descendants("serial").Single().Value;


        return elements.Select(el => new {Company = companyName, Serial = serialNumber, Value = el.Value});

有没有更好的方法来解析文件？(并提高性能？)

我试图解析一个在那里有日期的xml字符串.我想要填充的对象具有可为空的DateTime.但是如果我拉回的字符串有一个空值,我希望它是最小日期值.我想将它分配给变量？使用LINQ有一种简单的方法吗？

 IEnumerable<PatientClass> template = (IEnumerable<PatientClass>)(from templates in xDocument.Descendants("dataTemplateSpecification")//elem.XPathSelectElements(string.Format("//templates/template[./elements/element[@name=\"PopulationPatientID\"and @value='{0}' and @enc='{1}']]", "1", 0))
                                               select new PatientClass
                                               {
 PCPAppointmentDateTime = DateTime.Parse(templates.Descendants("element").SingleOrDefault(el => el.Attribute("name").Value == "PCPAppointmentDateTime").Attribute("value").Value),
 });

我正在使用的对象是......

 class PatientClass
 { 
   public DateTime? PCPAppointmentDateTime { get; set; }
 }

有任何想法吗？

我有以下xml:

<root ...>
  <Tables>
    <Table content="..">
    </Table>
    <Table content="interesting">
      <Item ...></Item>
      <Item ...></Item>
      <Item ...></Item>
    </Table>
    ...etc...
  </Tables>
</root>

我正在使用以下代码从"有趣"节点获取项目:

XElement xel = XElement.Parse(resp);

var nodes = from n in xel.Elements("Tables").Elements("Table")
            where n.Attribute("content").Value == "interesting"
            select n;

var items = from i in nodes.Elements()
            select i;

是否有更简单,更清洁的方法来实现这一目标？

我试图读取XML文件,但type of the expression in the select clause is incorrect. Type inference failed in the call to 'Select'由于以下查询而收到错误:

List<Data> dogs = (from q in doc.Descendants("dog")
    where (string)q.Attribute("name") == dogName
        select new Data
        {
            name = q.Attribute("name").Value,
            breed = q.Element("breed").Value,
            sex = q.Element("sex").Value
        }.ToList<Data>);

数据类:

public class Data
{
    public string name { get; set; }
    public string breed { get; set; }
    public string sex { get; set; }
    public List<string> dogs { get; set; }
}

运行这行代码时,我收到一个System.NullReferenceException.

// Occurs on this line
if (xDoc.Root.Element("data").Element("forecast").Element("record").Value == "0")
{
    tempnow.Text = xDoc.Root.Element("data").Element("forecast").Element("pop").Value;
}

Xdoc定义在类下面,如果这与它有关.

{
    public partial class MainPage : PhoneApplicationPage
    {

        XDocument xDoc;

这是我试图访问的XML文档,并找到"记录"的值.这也是"Xdoc"所代表的文档,其中包含以下信息.

<data>
  <status>success</status>
  <location>
    <city/>
    <fullName>39.6N, 0.3W - 6miles SW of El Puerto, SP</fullName>
    <localDate>2014-01-30T01:29:23</localDate>
    <localEpoch>1391045363</localEpoch>
    <locationID>GP202368</locationID>
  </location>
  <forecast>
    <record>0</record>
    <utcEpoch>1391040000</utcEpoch>
    <utcDate>2014-01-30T00:00:00</utcDate>
    <maxTempC>15.4</maxTempC>
    <maxTempF>59.7</maxTempF>
    <minTempC>5.2</minTempC>
    <minTempF>41.3</minTempF>
    <fcstDay>1</fcstDay>
    <dayLength>10:07</dayLength>
    <sunriseHHMMLocal>8:11am</sunriseHHMMLocal>
    <sunsetHHMMLocal>6:18pm</sunsetHHMMLocal>
    <nightLength/>
    <moonriseHHMMLocal/>
    <moonsetHHMMLocal/>
    <moonphase/>
    <moonillum/>
    <moonicon/>
    <pop>19</pop>
    <uv_index>2</uv_index>
    <gustC>30</gustC>
    <gustF>19</gustF>
    <heatindexC>-999.99</heatindexC>
    <heatindexF>-999.99</heatindexF>
    <icon>partly-cloudy-sm.png</icon>
    <iconBase>partly-cloudy</iconBase>
    <iconLg>partly-cloudy.png</iconLg>
    <prcpC>0</prcpC>
    <prcpF>0</prcpF>
    <rh>33</rh>
    <skyCover>8</skyCover>
    <snowC>0</snowC>
    <snowF>0</snowF>
    <wdir>NW</wdir>
    <windchillC>-999.99</windchillC>
    <windchillF>-999.99</windchillF> …