Develop Reference

Get all child element values of specific node using XPath

I'm using XPath to read elements from an XML document. Specifically I want to return the values of any element which is the child of a specified element (here the specified element is <SceneryType> and these elements have single-digit values. So I want to return all of the children of <SceneryType> 1 for example.
Here is the XML:
<MissionObjectives>
<Theme themeName="Gothic">
<SceneryType>
1
<Objective>
Do a river thing.
</Objective>
<Objective>
Get all men to the other side of the river.
</Objective>
</SceneryType>
<SceneryType>
2
<Objective>
Climb some trees!
</Objective>
<Objective>
Shoot the tree!
</Objective>
</SceneryType>
</Theme>
I've tried various ways of getting these child elements, but I can't figure it out. My //objective part of the expression just returns everything from the root it seems, but the iterator isn't running which seems odd, shouldn't it loop through every element if the expression is returning a nodelist of all the elements?
XPathDocument missionDoc = new XPathDocument(objectivesPath + "MissionObjectives" + chosenTheme + ".xml");
XPathNavigator nav = missionDoc.CreateNavigator();
foreach (Scenery scenery in world.currentWorld)
{
int sceneryType = scenery.type;
XPathExpression expr = nav.Compile($"MissionObjectives/Theme/SceneryType[text()='{sceneryType}']//Objective");
XPathNodeIterator iterator = nav.Select(expr);
while (iterator.MoveNext())
{
XPathNavigator nav2 = iterator.Current.Clone();
compatibleObjectivesList.Add(nav2.Value);
}
}
I've tried looking through Stack Overflow for similar questions but I can't seem to find anything which applies to XPath. I can't use LINQ to XML for this. Any idea how I can return all the values of the various 'Objective' nodes?
Cheers for any help!

its much simpler to use the XDocument:
var doc = XDocument.Load(objectivesPath + "MissionObjectives" + chosenTheme + ".xml");
to get all of the first SceneryType child nodes:
var node = doc.XPathSelectElement("//MissionObjectives/Theme/SceneryType[1]");
to get the second objective node:
var node = doc.XPathSelectElement("//MissionObjectives/Theme/SceneryType/Objective[2]");
more xpath samples

For one, your xml data has carriage returns, line feeds, and white spaces in the search element's text node. Keep in mind, that an XML node can be an element, attribute, or text (among other node types). The solution below is a bit on the "long-handed" side and perhaps a little "hacky", but it should work. I wasn't certain if you wanted the child element text data or the entire child element, but I return just the child text node data (without carriage returns and line feeds). Also, while this solution DOES NOT use LINQ to XML in the strictest sense, it does use one LINQ expression.
private List<string> getSceneryTypeObjectiveTextList(string xml, int sceneryTypeId, string xpath = "/MissionObjectives/Theme/SceneryType")
{
List<string> result = null;
XmlDocument doc = null;
XmlNodeList sceneryTypeNodes = null;
try
{
doc = new XmlDocument();
doc.LoadXml(xml);
sceneryTypeNodes = doc.SelectNodes(xpath);
if (sceneryTypeNodes != null)
{
if (sceneryTypeNodes.Count > 0)
{
foreach (XmlNode sceneryTypeNode in sceneryTypeNodes)
{
if (sceneryTypeNode.HasChildNodes)
{
var textNode = from XmlNode n in sceneryTypeNode.ChildNodes
where (n.NodeType == XmlNodeType.Text && n.Value.Replace("\r", "").Replace("\n", "").Replace(" ", "") == sceneryTypeId.ToString())
select n;
if (textNode.Count() > 0)
{
XmlNodeList objectiveNodes = sceneryTypeNode.SelectNodes("Objective");
if (objectiveNodes != null)
{
result = new List<string>(objectiveNodes.Count);
foreach (XmlNode objectiveNode in objectiveNodes)
{
result.Add(objectiveNode.InnerText.Replace("\r", "").Replace("\n", "").Trim());
}
// Could break out of the iteration, here, if we know that SceneryType is always unique (i.e. - no duplicates in Element text node)
}
}
}
}
}
}
}
catch (Exception ex)
{
// Handle error
}
finally
{
}
return result;
}
private sampleCall(string filePath, int sceneryTypeId)
{
List<string> compatibleObjectivesList = null;
try
{
compatibleObjectivesList = getSceneryTypeObjectiveTextList(File.ReadAllText(filePath), sceneryTypeId);
}
catch (Exception ex)
{
// Handle error
}
finally
{
}
}

How to iterate a xml file with XmlReader class

my xml stored in xml file which look like as below
<?xml version="1.0" encoding="utf-8"?>
<metroStyleManager>
<Style>Blue</Style>
<Theme>Dark</Theme>
<Owner>CSRAssistant.Form1, Text: CSR Assistant</Owner>
<Site>System.ComponentModel.Container+Site</Site>
<Container>System.ComponentModel.Container</Container>
</metroStyleManager>
this way i am iterating but some glitch is there
XmlReader rdr = XmlReader.Create(System.IO.Path.GetDirectoryName(System.Windows.Forms.Application.ExecutablePath) + #"\Products.xml");
while (rdr.Read())
{
if (rdr.NodeType == XmlNodeType.Element)
{
string xx1= rdr.LocalName;
string xx = rdr.Value;
}
}
it is always getting empty string xx = rdr.Value;
when element is style then value should be Blue as in the file but i am getting always empty....can u say why?
another requirement is i want to iterate always within <metroStyleManager></metroStyleManager>
can anyone help for the above two points. thanks

Blue is the value of Text node, not of Element node. You either need to add another if to get value of text nodes, or you can read inner xml of current element node:
rdr.MoveToContent();
while (rdr.Read())
{
if (rdr.NodeType == XmlNodeType.Element)
{
string name = rdr.LocalName;
string value = rdr.ReadInnerXml();
}
}
You can also use Linq to Xml to get names and values of root children:
var xdoc = XDocument.Load(path_to_xml);
var query = from e in xdoc.Root.Elements()
select new {
e.Name.LocalName,
Value = (string)e
};

You can use the XmlDocument class for this.
XmlDocument doc = new XmlDocument.Load(filename);
foreach (XmlNode node in doc.ChildNodes)
{
if (node.ElementName == "metroStyleManager")
{
foreach (XmlNode subNode in node.ChildNodes)
{
string key = subNode.LocalName; // Style, Theme, etc.
string value = subNode.Value; // Blue, Dark, etc.
}
}
else
{
...
}
}

you can user XDocument xDoc = XDocument.Load(strFilePath) to load XML file.
then you can use
foreach (XElement xeNode in xDoc.Element("metroStyleManager").Elements())
{
//Check if node exist
if (!xeNode.Elements("Style").Any()
//If yes then
xeNode.Value
}
Hope it Helps...
BTW, its from System.XML.Linq.XDocument

Concatenate XML Node data

I have XML look like this
<BoxResult>
<DocumentType>BCN</DocumentType>
<DocumentID>BCN_20131113_1197005001#854#11XEZPADAHANDELC</DocumentID>
<DocumentVersion>1</DocumentVersion>
<ebXMLMessageId>CENTRAL_MATCHING</ebXMLMessageId>
<State>FAILED</State>
<Timestamp>2013-11-13T13:02:57</Timestamp>
<Reason>
<ReasonCode>efet:IDNotFound</ReasonCode>
<ReasonText>Unknown Sender</ReasonText>
</Reason>
<Reason>
<ReasonCode>efet:IDNotFound</ReasonCode>
<ReasonText>Unknown Receiver</ReasonText>
</Reason>
</BoxResult>
In my C# code , i need to parse through the XML and concatenate the Reason Text Data.
Basically , i need the output as Unknown Sender ; Unknown Receiver
I tried the following code but i am not getting the desired output
XmlNodeList ReasonNodeList = xmlDoc.SelectNodes(/BoxResult/Reason);
foreach (XmlNode xmln in ReasonNodeList)
{
ReasonText = ReasonText + ";" + xmlDoc.SelectSingleNode(/BoxResult/Reason/ReasonText).InnerXml.ToString();
}
if (ReasonText != " ")
{
ReasonText = ReasonText.Substring(1);
}
The output i am getting from this code is Unknown Sender ; Unknown Sender
It is not displaying Unknown Receiver
Please advise and your help will be useful

You are always using the same node to retrieve the data. The xmlDoc is always called (i.e. the first <Reason> node), instead of each targeted node.
XmlNodeList ReasonNodeList = xmlDoc.SelectNodes("/BoxResult/Reason/ReasonText"); //change here
foreach (XmlNode xmln in ReasonNodeList)
{
ReasonText = ReasonText + ";" + xmln.InnerXml.ToString(); //change here
}
if (ReasonText != " ")
{
ReasonText = ReasonText.Substring(1);
}

You're iterating through <Reason> nodes and each time selecting the first /BoxResult/Reason/ReasonText node in document (note you're not using your xmln variable anywhere).
By the way, here's a shorter version (replaces your whole code block):
ReasonText += String.Join(";",
xmlDoc.SelectNodes("/BoxResult/Reason/ReasonText")
.Cast<XmlNode>()
.Select(n => n.InnerText));

Reading multiple child nodes of xml file

I have created an Xml file with example contents as follows:
<?xml version="1.0" encoding="utf-8" ?>
<Periods>
<PeriodGroup name="HER">
<Period>
<PeriodName>Prehistoric</PeriodName>
<StartDate>-500000</StartDate>
<EndDate>43</EndDate>
</Period>
<Period>
<PeriodName>Iron Age</PeriodName>
<StartDate>-800</StartDate>
<EndDate>43</EndDate>
</Period>
<Period>
<PeriodName>Roman</PeriodName>
<StartDate>43</StartDate>
<EndDate>410</EndDate>
</Period>
</PeriodGroup>
<PeriodGroup name="CAFG">
<Period>
<PeriodName>Prehistoric</PeriodName>
<StartDate>-500000</StartDate>
<EndDate>43</EndDate>
</Period>
<Period>
<PeriodName>Roman</PeriodName>
<StartDate>43</StartDate>
<EndDate>410</EndDate>
</Period>
<Period>
<PeriodName>Anglo-Saxon</PeriodName>
<StartDate>410</StartDate>
<EndDate>800</EndDate>
</Period>
</PeriodGroup>
</Periods>
I need to be able to read the Period node children within a selected PeriodGroup. I guess the PeriodName could be an attribute of Period if that is more sensible.
I have looked at loads of examples but none seem to be quite right and there seems to be dozens of different methods, some using XmlReader, some XmlTextReader and some not using either. As this is my first time reading an Xml file, I thought I'd ask if anyone could give me a pointer. I've got something working just to try things out, but it feels clunky. I'm using VS2010 and c#. Also, I see a lot of people are using LINQ-Xml, so I'd appreciate the pros and cons of using this method.
string PG = "HER";
XmlDocument doc = new XmlDocument();
doc.Load(Server.MapPath("./Xml/XmlFile.xml"));
string text = string.Empty;
XmlNodeList xnl = doc.SelectNodes("/Periods/PeriodGroup");
foreach (XmlNode node in xnl)
{
text = node.Attributes["name"].InnerText;
if (text == PG)
{
XmlNodeList xnl2 = doc.SelectNodes("/Periods/PeriodGroup/Period");
foreach (XmlNode node2 in xnl2)
{
text = text + "<br>" + node2["PeriodName"].InnerText;
text = text + "<br>" + node2["StartDate"].InnerText;
text = text + "<br>" + node2["EndDate"].InnerText;
}
}
Response.Write(text);
}

You could use an XPath approach like so:
XmlNodeList xnl = doc.SelectNodes(string.Format("/Periods/PeriodGroup[#name='{0}']/Period", PG));
Though prefer LINQ to XML for it's readability.
This will return Period node children based on the PeriodGroup name attribute supplied, e.g. HER:
XDocument xml = XDocument.Load(HttpContext.Current.Server.MapPath(FileLoc));
var nodes = (from n in xml.Descendants("Periods")
where n.Element("PeriodGroup").Attribute("name").Value == "HER"
select n.Element("PeriodGroup").Descendants().Elements()).ToList();
Results:
<PeriodName>Prehistoric</PeriodName>
<StartDate>-500000</StartDate>
<EndDate>43</EndDate>
<PeriodName>Iron Age</PeriodName>
<StartDate>-800</StartDate>
<EndDate>43</EndDate>
<PeriodName>Roman</PeriodName>
<StartDate>43</StartDate>
<EndDate>410</EndDate>
The query is pretty straightforward
from n in xml.Descendants("Periods")
Will return a collection of the descendant elements for the element Periods.
We then use where to filter this collection of nodes based on attribute value:
where n.Element("PeriodGroup").Attribute("name").Value == "HER"
Will then filter down the collection to PeriodGroup elements that have a name attribute with a value of HER
Finally, we select the PeriodGroup element and get it's descendant nodes
select n.Element("PeriodGroup").Descendants().Elements()
EDIT (See comments)
Since the result of this expression is just a query, we use .ToList() to enumerate the collection and return an object containing the values you need. You could also create anonymous types to store the element values for example:
var nodes = (from n in xml.Descendants("Period").
Where(r => r.Parent.Attribute("name").Value == "HER")
select new
{
PeriodName = (string)n.Element("PeriodName").Value,
StartDate = (string)n.Element("StartDate").Value,
EndDate = (string)n.Element("EndDate").Value
}).ToList();
//Crude demonstration of how you can reference each specific element in the result
//I would recommend using a stringbuilder here..
foreach (var n in nodes)
{
text += "<br>" + n.PeriodName;
text += "<br>" + n.StartDate;
text += "<br>" + n.EndDate;
}
This is what the nodes object will look like after the query has run:

Since the XmlDocument.SelectNodes method actually accepts an XPath expression, you're free to go like this:
XmlNodeList xnl = doc.SelectNodes("/Periods/PeriodGroup[#name='" + PG + "']/Period");
foreach (XmlNode node in xnl) {
// Every node here is a <Period> child of the relevant <PeriodGroup>.
}
You can learn more on XPath at w3schools.

go thru this
public static void XMLNodeCheck(XmlNode xmlNode)
{
if (xmlNode.HasChildNodes)
{
foreach (XmlNode node in xmlNode)
{
if (node.HasChildNodes)
{
Console.WriteLine(node.Name);
if (node.Attributes.Count!=0)
{
foreach (XmlAttribute att in node.Attributes)
{
Console.WriteLine("----------" + att.Name + "----------" + att.Value);
}
}
XMLNodeCheck(node);//recursive function
}
else
{
if (!node.Equals(XmlNodeType.Element))
{
Console.WriteLine(node.InnerText);
}
}
}
}
}

Change Value of the last Attribute in an XML c#

I was working on a bunch of XMLs that all share an attribute that contains the string "name" in them. The following code selects the attribute with string "name" in it and assign a new value to it.
public void updateXmlFile(string strFileName)
{
try
{
//Load the Document
XmlDocument doc = new XmlDocument();
doc.Load(strFileName);
//Set the changed Value
string newValue = GetUniqueKey();
//Select all nodes in the XML then choose from them
//the first node that contain string "name" in it
XmlNodeList list = doc.SelectNodes("//#*");
XmlNode filteredNode = list.Cast<XmlNode>()
.First(item => item.Name.ToLower().Contains("name"));
//Assign the newValue to the value of the node
filteredNode.Value = newValue;
doc.Save(strFileName);
}
catch (XmlException xex) { Console.WriteLine(xex); }
}
Now a new XMLs were added that dosen't have the string "name" in them, so instead of modifying the attribute with string "name" in it I decided to simply modify the last attribute no matter what it was (not the first)
Can anybody tell me how to do that?
EDIT
Here is an example of my XML
<?xml version="1.0" encoding="utf-8"?>
<CO_CallSignLists Version="24" ModDttm="2010-09-13T06:45:38.873" ModUser="EUADEV\SARE100" ModuleOwner="EUADEVS06\SS2008" CreateDttm="2009-11-05T10:19:31.583" CreateUser="EUADEV\A003893">
<CoCallSignLists DataclassId="E3FC5E2D-FE84-492D-AD94-3ACCED870714" EntityId="E3FC5E2D-FE84-492D-AD94-3ACCED870714" MissionID="4CF71AB2-0D92-DE11-B5D1-000C46F3773D" BroadcastType="S" DeputyInSpecialList="1" SunSpots="1537634cb70c6d80">
<CoCallSigns EntityId="DEBF1DDB-3C92-DE11-A280-000C46F377C4" CmdID="C45F3EF1-1292-DE11-B5D1-000C46F3773D" ModuleID="6CB497F3-AD63-43F1-ACAE-2C5C3B1D7F61" ListType="HS" Name="Reda Sabassi" Broadcast="INTO" PhysicalAddress="37" IsGS="1" HCId="0" CommonGeoPos="1" GeoLat="0.0000000" GeoLong="0.0000000">
<CoRadios EntityId="E1BF1DDB-3C92-DE11-A280-000C46F377C4" RadioType="HF" />
</CoCallSigns>
</CoCallSignLists>
</CO_CallSignLists>
#Alex: You notice that the "SunSpots" attribute (last attribute in the first child element) is successfully changed. But now when I wanna load the XML back into the DB it gives me an error
Here is the modified code
public void updateXmlFile(string strFileName)
{
try
{
XDocument doc = XDocument.Load(strFileName);
XAttribute l_attr_1 = (doc.Elements().First().Elements().First().Attributes().Last());
l_attr_1.Value = GetUniqueKey();
Console.WriteLine("Name: {0} Value:{1}", l_attr_1.Name, l_attr_1.Value);
doc.Save(strFileName);
}
catch (XmlException xex) { Console.WriteLine(xex); }
}
I was thinking of making an if statment which checks if the XML has an attribute that contains string "name" in it (since most of my XMLs has an attribute that contains name in them) if it does then change the attribute's value if not look for the last attribute and change it.. not the best solution but just throwing it out there

Then definitely use Linq to XML.
Example:
using System.Xml.Linq;
string xml = #"<?xml version=""1.0"" encoding=""utf-8""?>
<Commands Version=""439"" CreateUser=""Reda"">
<CmCommands DataclassId=""57067ca8-ef96-4d2e-a085-6bd7e8b24126"" OrderName = ""Tea"" Remark=""Black"">
<CmExecutions EntityId=""A9A5B0F2-6AB4-4619-9106-B0F85F86EE01"" Lock=""n"" />
</CmCommands>
</Commands>";
XDocument x = XDocument.Parse(xml);
Debug.Print(x.Elements().First().Elements().First().Attributes().Last().Value);
// Commands ^ CmCommands ^ Remark ^
That is, word for word, the last attribute of the first child of the first element.
You can also query for element/attribute names, like:
Debug.Print(x.Descendants(XName.Get("CmCommands", "")).First().Attribute(XName.Get("Remark", "")).Value);
And of course you can use all of the Linq goodness like Where, Select, Any, All etc.
Note: replace XDocument.Parse with XDocument.Load if appropriate etc.

I've not tested this but you should be able to do all of this in the XPath expression. Something like this:
//#*[contains(node-name(.), 'name')][last()]
This will return only the last attribute with the string name anywhere in its name.
If you only want the last attribute, irrespective of it's name, use this:
//#*[last()]

Look at class XmlAttributeCollection. You can get this collection by reading property Attributes of XmlNode. Just get the last by index.

Instead of .First(), use an extension method like this:
public static T LastOrDefault<T>(this IEnumerable<T> list)
{
T val = null;
foreach(T item in list)
{
val = item;
}
return val;
}