How to Select XML node, given only the attribute name - c#

I have an XML file as follow
<NODE1 attribute1 = "SomeValue" attribute2 = "SomeOtherValue" />
<NODE2 attribute3 = "SomeValue" attribute4 = "SomeOtherValue" />
Now I am given only the attribute name say "attribute3". How can I get the name of node?

Add the following namespace at the top of your file:
using System.Xml.Linq;
And try this (assuming that input.xml is the path to your XML file):
var xml = XDocument.Load("input.xml");
string nodeName;
var node = xml.Descendants()
.FirstOrDefault(e => e.Attribute("attribute3") != null);
if (node != null)
nodeName = node.Name.LocalName;

With LINQ to XML:
XDocument xdoc = XDocument.Load(path_to_xml);
var nodes = xdoc.Descendants().Where(e => e.Attribute("attribute3") != null);
Or with XPath (as Marvin suggested):
var nodes = xdoc.XPathSelectElements("//*[#attribute3]");
Both queries will return collection of XElement nodes which have attribute attribute3 defined. You can get first of them with FirstOrDefault. If you want to get just name, use node.Name.LocalName.
UPDATE: I do not recommend you to use XmlDocument, but if you already manipulating this xml document, then loading it second time with XDocument could be inefficient. So, you can select nodes with XPathNavigator:
var doc = new XmlDocument();
doc.Load(path_to_xml);
var naviagator = doc.CreateNavigator();
var nodeIterator = naviagator.Select("//*[#attribute3]");

try in this way
string nodeName;
if(Node.Attributes.Cast<XmlAttribute>().Any(x => x.Name == "attribute3"))
{
nodeName=Node.Name;
}

Related

How to select an attribute in XML based on the value of another attribute?

Currently I am able to select attributes in an XML document because they are uniquely identifiable, like this:
XmlDocument weatherData = new XmlDocument();
weatherData.Load(query);
XmlNode channel = weatherData.SelectSingleNode("rss").SelectSingleNode("channel");
XmlNamespaceManager man = new XmlNamespaceManager(weatherData.NameTable);
man.AddNamespace("yweather", "http://xml.weather.yahoo.com/ns/rss/1.0");
town = channel.SelectSingleNode("yweather:location", man).Attributes["city"].Value;
But how do I select the "text" attribute from a node of the same name (yweather:forecast)?
<yweather:forecast day="Sat" text="Sunny" code="32"/>
<yweather:forecast day="Sun" text="Partly Cloudy" code="30"/>
<yweather:forecast day="Mon" text="AM Showers" code="39"/>
<yweather:forecast day="Tue" text="Cloudy" code="26"/>
<yweather:forecast day="Wed" text="Cloudy/Wind" code="24"/>
Is there a conditional statement I can use to only select the text attribute where the day attribute is equal to "Mon"?
Something like this will work:
string xml = "YourXml";
XElement doc = XElement.Parse(xml);
var Result = from a in doc.Descendants("yweather:forecast")
where a.Attribute("day").Value == "Mon"
select a.Attribute("text").Value;
or lambda syntax:
var Result = doc.Descendants("yweather:forecast")
.Where(x=> x.Attribute("day").Value == "Mon")
.Select(x=> x.Attribute("text").Value);
you can also refer this SO post

Adding info to a xml file

I have a XML file which contains about 850 XML nodes. Like this:
<NameValueItem>
<Text>Test</Text>
<Code>Test</Code>
</NameValueItem>
........ 849 more
And I want to add a new Childnode inside each and every Node. So I end up like this:
<NameValueItem>
<Text>Test</Text>
<Code>Test</Code>
<Description>TestDescription</Description>
</NameValueItem>
........ 849 more
I've tried the following:
XmlDocument doc = new XmlDocument();
doc.Load(xmlPath);
XmlNodeList nodes = doc.GetElementsByTagName("NameValueItem");
Which gives me all of the nodes, but from here am stuck(guess I need to iterate over all of the nodes and append to each and every) Any examples?
You need something along the lines of this example below. On each of your nodes, you need to create a new element to add to it. I assume you will be getting different values for the InnerText property, but I just used your example.
foreach (var rootNode in nodes)
{
XmlElement element = doc.CreateElement("Description");
element.InnerText = "TestDescription";
root.AppendChild(element);
}
You should just be able to use a foreach loop over your XmlNodeList and insert the node into each XmlNode:
foreach(XmlNode node in nodes)
{
node.AppendChild(new XmlNode()
{
Name = "Description",
Value = [value to insert]
});
}
This can also be done with XDocument using LINQ to XML as such:
XDocument doc = XDocument.Load(xmlDoc);
var updated = doc.Elements("NameValueItem").Select(n => n.Add(new XElement() { Name = "Description", Value = [newvalue]}));
doc.ReplaceWith(updated);
If you don't want to parse XML using proper classes (i.e. XDocument), you can use Regex to find a place to insert your tag and insert it:
string s = #"<NameValueItem>
<Text>Test</Text>
<Code>Test</Code>
</NameValueItem>";
string newTag = "<Description>TestDescription</Description>";
string result = Regex.Replace(s, #"(?<=</Code>)", Environment.NewLine + newTag);
but the best solution is Linq2XML (it's much better, than simple XmlDocument, that is deprecated at now).
string s = #"<root>
<NameValueItem>
<Text>Test</Text>
<Code>Test</Code>
</NameValueItem>
<NameValueItem>
<Text>Test2</Text>
<Code>Test2</Code>
</NameValueItem>
</root>";
var doc = XDocument.Load(new StringReader(s));
var elms = doc.Descendants("NameValueItem");
foreach (var element in elms)
{
element.Add(new XElement("Description", "TestDescription"));
}
var text = new StringWriter();
doc.Save(text);
Console.WriteLine(text);

Looping through xmlnodes using Xdocument

I have an xml string like this
<Test>
<ConnectionParameters>
<ConnectionParameter DisplayName="asd" Id="cgfh" IsPassword="false" IsRequired="true"> </ConnectionParameter>
<ConnectionParameter DisplayName="asdasd" Id="fgh" IsPassword="false" IsRequired="true"></ConnectionParameter>
<ConnectionParameter DisplayName="asdasd" Id="hdfh" IsPassword="false" IsRequired="true"></ConnectionParameter>
<ConnectionParameter DisplayName="asdad" Id="dfgdf" IsPassword="false" IsRequired="true"> </ConnectionParameter>
</ConnectionParameters>
</Test>
How can I loop through each "ConnectionParameter" tag inorder to get the attributes like Id,DisplayName etc using xdocument?
I tried like this,
XDocument xdoc = new XDocument();
xdoc= XDocument.Parse(fileContent);
var saveResult = from b in xdoc.Descendants("ConnectionParameters")
select new
{
success = (string)b.Element("ConnectionParameter").Attribute("Id").Value ?? string.Empty,
};
But it only returns the first node only
You're currently looping through all the ConnectionParameters elements (of which there's only one) and selecting the first ConnectionParameter element (using the Element call). You want to just loop through the ConnectionParameter elements:
// Note the lack of creating a new XDocument for no reason
XDocument xdoc = XDocument.Parse(fileContent);
var saveResult = from b in xdoc.Descendants("ConnectionParameter")
select new
{
success = (string) b.Attribute("Id") ?? ""
};
Or to avoid creating an anonymous type for no obvious reason, and using plain "dot notation" as the query expression isn't helping you much:
XDocument xdoc = XDocument.Parse(fileContent);
var saveResult = xdoc.Descendants("ConnectionParameter")
.Select(b => (string) b.Attribute("Id") ?? "");
If you prefer to make the parent element names explicit, you could use:
XDocument xdoc = XDocument.Parse(fileContent);
var saveResult = xdoc.Element("Test")
.Element("ConnectionParameters")
.Descendants("ConnectionParameter")
.Select(b => (string) b.Attribute("Id") ?? "");
Or:
XDocument xdoc = XDocument.Parse(fileContent);
var saveResult = xdoc.Root
.Element("ConnectionParameters")
.Descendants("ConnectionParameter")
.Select(b => (string) b.Attribute("Id") ?? "");
Load your xml into xDocument, then you can do something like this (can't remember exact syntax)
xDoc.Root.Descendants("ConnectionParameters").Attribute("DisplayName").Value;

Get node property of XmlDocument in C#

I'm using this xml structure:
<park>
<car title="Ferrari" available="true">
<url>http://www.ferrari.com/</url>
</rss>
</park>
And this is my code in C#:
XmlDocument doc = new XmlDocument();
doc.Load("Settings.xml");
XmlNodeList list = doc.SelectNodes("/park/car");
foreach (XmlNode item in list)
{
string x = item["#title"].InnerText;
}
I just want to get "title" property but i can't get it working. I'm using "#" but without success.
Try this code:
string x = item.Attributes["title"].Value;
I suggest you to use LINQ to XML for parsing xml:
var xdoc = XDocument.Load("Settings.xml");
var titles = xdoc.XPathSelectElements("//park/car")
.Select(c => (string)c.Attribute("title"));
Or without XPath:
var titles = xdoc.Descendants("park")
.Elements("car")
.Select(c => (string)c.Attribute("title"));

Locating XML node by child node value inside of it, and changing another value

Three part question.
Is it possible to locate a specific XML node by a child inside of it to retrieve other children of the parent? Example:
<House>
<Kitchen>
<Appliance>
<Name>Refrigerator</Name>
<Brand>Maytag</Brand>
<Model>F2039-39</Model>
</Appliance>
<Appliance>
<Name>Toaster</Name>
<Brand>Black and Decker</Brand>
<Model>B8d-k30</Model>
</Appliance>
</Kitchen>
</House>
So for this, I would like to locate the appropriate Appliance node by searching for "Refrigerator" or "Toaster", and retrieve the brand from it.
The second part of this question is this: Is this a stupid way to do it? Would using an attribute in the Appliance tag make this a lot easier? If so, how would I locate it that way?
As for the third part, once I locate the Appliance, how would I go about changing say, the Model, of that particular appliance?
Using XLinq, you can perform this query fairly naturally:
// Given:
// var xdoc = XDocument.Load(...);
// string applianceName = "Toaster";
// Find the appliance node who has a sub-element <Name> matching the appliance
var app = xdoc.Root
.Descendants("Appliance")
.SingleOrDefault(e => (string)e.Element("Name") == applianceName);
// If we've found one and it matches, make a change
if (app != null)
{
if (((string)app.Element("Model")).StartsWith("B8d-k30"))
{
app.Element("Model").Value = "B8d-k30 Mark II";
}
}
xdoc.Save(#"output.xml"); // save changes back to the document
Well if you are using XmlDocument
foreach(XmlNode applianceNode in
myDocument.DocumentElement.SelectNodes("Kitchen/Applicance[Name='Refrigerator']")
{
XmlNode modelNode = applicianceNode.SelectSingleNode("Model").InnerText = SomeOtherValue;
}
if you made the name tag an attribute (applicanceName) it would make little difference to this.
foreach(XmlNode applianceNode in
myDocument.DocumentElement.SelectNodes("Kitchen/Applicance[#applianceName='Refrigerator']")
{
// ...
}
string xml = #"<House>
<Kitchen>
<Appliance>
<Name>Refrigerator</Name>
<Brand>Maytag</Brand>
<Model>F2039-39</Model>
</Appliance>
<Appliance>
<Name>Toaster</Name>
<Brand>Black and Decker</Brand>
<Model>B8d-k30</Model>
</Appliance>
</Kitchen>
</House>";
XDocument xdoc = XDocument.Parse(xml);
string newModel = "B8d-k45";
var matchingElement = (from appliance in xdoc.Descendants("Appliance")
where appliance.Element("Name").Value == "Toaster"
select appliance).FirstOrDefault();
if (matchingElement != null)
{
matchingElement.Element("Model").Value = newModel;
}
Console.WriteLine(xdoc.ToString());
Necromancing.
Yes, it's even simpler with XPath, and works completely without Linq:
Just use .. to get to the parent node (on the second thought, Linq will be easier when using "ordinalignorecase")
public static void CreateNewHouse()
{
System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
doc.XmlResolver = null;
doc.Load(#"d:\House.xml");
foreach (System.Xml.XmlNode modelNode in doc.DocumentElement
.SelectNodes("/House/Kitchen/Appliance/Name[text()='Refrigerator']/../Model"))
{
modelNode.InnerText = "A New Value";
}
doc.Save(#"d:\MyHouse.xml");
}
MyHouse.xml:
<House>
<Kitchen>
<Appliance>
<Name>Refrigerator</Name>
<Brand>Maytag</Brand>
<Model>A New Value</Model>
</Appliance>
<Appliance>
<Name>Toaster</Name>
<Brand>Black and Decker</Brand>
<Model>B8d-k30</Model>
</Appliance>
</Kitchen>
</House>
If you need it case-insensitive, replace text() with this:
translate(text(), 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz')
(for ASCII/english-only) and of course change "Refrigerator" to lowercase ("refrigerator")
If the XML-document has a default-namespace, you need to supply it in Select*Node, e.g.
xnImageTag.SelectSingleNode("./dft:Source", nsmgr);
where
System.Xml.XmlNamespaceManager nsmgr = GetReportNamespaceManager(doc);
public static System.Xml.XmlNamespaceManager GetReportNamespaceManager(System.Xml.XmlDocument doc)
{
if (doc == null)
throw new ArgumentNullException("doc");
System.Xml.XmlNamespaceManager nsmgr = new System.Xml.XmlNamespaceManager(doc.NameTable);
// <Report xmlns="http://schemas.microsoft.com/sqlserver/reporting/2008/01/reportdefinition" xmlns:rd="http://schemas.microsoft.com/SQLServer/reporting/reportdesigner">
if (doc.DocumentElement != null)
{
string strNamespace = doc.DocumentElement.NamespaceURI;
System.Console.WriteLine(strNamespace);
nsmgr.AddNamespace("dft", strNamespace);
return nsmgr;
}
nsmgr.AddNamespace("dft", "http://schemas.microsoft.com/sqlserver/reporting/2005/01/reportdefinition");
// nsmgr.AddNamespace("dft", "http://schemas.microsoft.com/sqlserver/reporting/2008/01/reportdefinition");
return nsmgr;
} // End Function GetReportNamespaceManager

Categories

Resources