C＃XML如何通过属性检索字段的innerText？

Question

Here is the XML sample:

  <?xml version="1.0" ?> 
  <XMLScreen xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <CX>80</CX> 
  <CY>24</CY> 
  <Formatted>true</Formatted> 
  <Field>
  <Location position="1" left="1" top="0" length="69" /> 
  <Attributes Base="226" Protected="false" FieldType="High" /> 
  *SDC SCHEDULING CATEGORY UPDATE 
  </Field>
  </XMLScreen>

I want to retrive the Inner text of each field based on its Location position .

What I have so far is:

  XmlDocument xmlDoc = new XmlDocument();
  xmlDoc.LoadXml(myEm.CurrentScreenXML.GetXMLText());
  XmlNodeList fields = xmlDoc.GetElementsByTagName("Field");

  MessageBox.Show("Field spot: " + i + " Contains: " + fields[i].InnerText);

And I want to be able to just extract the inner text of the field by passing in a number of the location position. So if I say foo[i] I want to be able to get the innertext

*SDC SCHEDULING CATEGORY UPDATE

Answer 1

Something like that, with XDocument instead of XmlDocument (well, if you're not in .net 3.5 or higher, we'll have a problem).

private string GetTextByLocationId(XDocument document, int id)
{
     var field = document.Descendants("Field").FirstOrDefault(m => m.Element("Location").Attribute("position").Value == id.ToString());
     if (field == null) return null;
     return field.Value;
}

and usage

var xDocument = XDocument.Load(<pathToXmlFile or XmlReader or string or ...>);
var result = GetTextByLocationId(xDocument, 1);

EDIT

or if you want a dictionary with :key = position / value = text

private static Dictionary<int, string> ParseLocationAndText(XDocument document)
        {
            var fields = document.Descendants("Field");
            return fields.ToDictionary(
                 f => Convert.ToInt32(f.Element("Location").Attribute("position").Value),
                 f => f.Value);
        }

Answer 2

You should use a xpath search query :

  XmlDocument xmlDoc = new XmlDocument();
  xmlDoc.LoadXml(xml);
  int nodeId = 4;
  XmlNode node = xmlDoc.SelectSingleNode(String.Format(@"//Location[@position='{0}']", nodeId));
  if (node != null)
  {
      String field = node.ParentNode.InnerText;
  }

Answer 3

Try,

XElement root = XElement.Parse(myEm.CurrentScreenXML.GetXMLText());
XElement field = root.XPathSelectElement(
                    string.Format("Field[Location/@position='{0}']", 1));
string text = field.Value;

You will need to use the following using to use XPath with XElements.

using System.Xml.XPath;