Question

I mumped (again) with an 误解 of XDocument/Linq. 关于下文的XML,我有<代码>名称En和-provinceCode,作为我的代码中的变量。我试图确定<代码>代码(例如,和,因为我有另外两个要素。 The provinceCode and NameEn joint are separate in the XML (noplica).



<siteList>
  <site code="s0000001">
    <nameEn>Edmonton</nameEn>
    <nameFr>Edmonton</nameFr>
    <provinceCode>AB</provinceCode>
  </site>
  <site code="s0000002">
    <nameEn>Algonquin Park</nameEn>
    <nameFr>Parc Algonquin</nameFr>
    <provinceCode>ON</provinceCode>
  </site>
...
</siteList>


Here s the code I m trying (my XML is in the "loaded" XDocument:

selectedProvince = "ON";
selectedCity = "Algonquin Park";      
strSiteCode = loaded.Descendants("site")
    .Where(x => x.Element("provinceCode").Value == selectedProvince)
    .Where(x => x.Element("nameEn").Value == selectedCity)
    .Select(x => x.Element("code").Value)
    .ToString();
strNameFR = loaded.Descendants("site")
    .Where(x => x.Element("provinceCode").Value == selectedProvince)
    .Where (x => x.Element("nameEn").Value == selectedCity)
    .Select(x => x.Element("nameFr").Value)
    .ToString();


The string strSiteCode returns: System.Linq.Enumerable+WhereSelectEnumerableIterator2[System.Xml.Linq.XElement,System.String]andstrNameFRreturns""`.

I can t figure out what the working code should look like.  Thanks for any help.

Doug

Answer 1

我或许会把它照做:

get the list of matching <site> nodes once
iterate over all matches (typically only one)
get the code attribute and nameFr element from those matching items

法典希望:

// determine the matching list of <site> nodes ...
var selectedSites = loaded
                       .Descendants("site")
                       .Where(x => x.Element("provinceCode").Value == selectedProvince)
                       .Where(x => x.Element("nameEn").Value == selectedCity);

// iterate over all matching <site> nodes
foreach (var site in selectedSites)
{
    // grab the code attribute and nameFr element from <site> node
    var siteCode = site.Attribute("code").Value;
    var nameFR = site.Element("nameFr").Value;
}

Answer 2


提 出

var result = loaded.Descendants("site")
    .Where(x => (x.Element("provinceCode").Value == selectedProvince) &&
                 (x.Element("nameEn").Value == selectedCity) )
    .Select(x => x.Element("code").Value)
    .SingleOrDefault();

if (result != null)
{
    strSiteCode = result.ToString();
}

<代码>选择(>>称收复(在你看来,只有一元)。因此,请打电话<代码>SingleOrDefault()(或Single(<>>)。另外,我删除了第二个<代码>(),并列入了第一个<代码>()的条件。

Answer 3

考虑到“x.Element(......)”方法有可能使“Value”(......)”法失效,因此获得“Value”(......)将造成无效。假设您的xml不得always 各省或省。如果是的话,你就没有问题了,但你不想在释放法中排除这种可能。下面解决了无效的问题。

var site = loaded
    .Descendants("site")
    .FirstOrDefault(x => (string)x.Element("provinceCode") == selectedProvince &&
                    x => (string)x.Element("nameEn") == selectedCity);    

if (site == null)
{
    return
}

var siteCode = (string)site.Attribute("code");
var nameFr = (string)site.Element("nameFr");

友情链接