Load function is already defined in xmlData class
public class XmlData
{
public void Load(XElement xDoc)
{
var id = xDoc.XPathSelectElements("//ID");
var listIds = xDoc.XPathSelectElements("/Lists//List/ListIDS/ListIDS");
}
}
I'm just calling the Load function from my end.
XmlData aXmlData = new XmlData();
string input, stringXML = "";
TextReader aTextReader = new StreamReader("D:\\test.xml");
while ((input = aTextReader.ReadLine()) != null)
{
stringXML += input;
}
XElement Content = XElement.Parse(stringXML);
aXmlData.Load(Content);
in load function,im getting both id and and listIds as null.
My test.xml contains
<SEARCH>
<ID>11242</ID>
<Lists>
<List CURRENT="true" AGGREGATEDCHANGED="false">
<ListIDS>
<ListID>100567</ListID>
<ListID>100564</ListID>
<ListID>100025</ListID>
<ListID>2</ListID>
<ListID>1</ListID>
</ListIDS>
</List>
</Lists>
</SEARCH>
EDIT: Your sample XML doesn't have an id element in the namespace with the nss alias. It would be <nss:id> in that case, or there'd be a default namespace set up. I've assumed for this answer that in reality the element you're looking for is in the namespace.
Your query is trying to find an element called id at the root level. To find all id elements, you need:
var tempId = xDoc.XPathSelectElements("//nss:id", ns);
... although personally I'd use:
XDocument doc = XDocument.Parse(...);
XNamespace nss = "http://schemas.microsoft.com/SQLServer/reporting/reportdesigner";
// Or use FirstOrDefault(), or whatever...
XElement idElement = doc.Descendants(nss + "id").Single();
(I prefer using the query methods on LINQ to XML types instead of XPath... I find it easier to avoid silly syntax errors etc.)
Your sample code is also unclear as you're using xDoc which hasn't been declared... it helps to write complete examples, ideally including everything required to compile and run as a console app.
I am looking at the question 3 hours after it was submitted and 41 minutes after it was (last) edited.
There are no namespaces defined in the provided XML document.
var listIds = xDoc.XPathSelectElements("/Lists//List/ListIDS/ListIDS");
This XPath expression obviously doesn't select any node from the provided XML document, because the XML document doesn't have a top element named Lists (the name of the actual top element is SEARCH)
var id = xDoc.XPathSelectElements("//ID");
in load function,im getting both id and and listIds as null.
This statement is false, because //ID selects the only element named ID in the provided XML document, thus the value of the C# variable id is non-null. Probably you didn't test thoroughly after editing the XML document.
Most probably the original ID element belonged to some namespace. But now it is in "no namespace" and the XPath expression above does select it.
string xmldocument = "<response xmlns:nss=\"http://schemas.microsoft.com/SQLServer/reporting/reportdesigner\"><action>test</action><id>1</id></response>";
XElement Content = XElement.Parse(xmldocument);
XPathNavigator navigator = Content.CreateNavigator();
XmlNamespaceManager ns = new XmlNamespaceManager(navigator.NameTable);
ns.AddNamespace("nss", "http://schemas.microsoft.com/SQLServer/reporting/reportdesigner");
var tempId = navigator.SelectSingleNode("/id");
The reason for the null value or system returned value is due to the following
var id = xDoc.XPathSelectElements("//ID");
XpathSElectElements is System.xml.linq.XElment which is linq queried date. It cannot be directly outputed as such.
To Get individual first match element
use XPathSelectElement("//ID");
You can check the number of occurrences using XPathSelectElements as
var count=xDoc.XPathSelectElements("//ID").count();
you can also query the linq statement as order by using specific conditions
Inorder to get node value from a list u can use this
foreach (XmlNode xNode in xDoc.SelectNodes("//ListIDS/ListID"))
{
Console.WriteLine(xNode.InnerText);
}
For Second list you havnt got the value since, the XPath for list items is not correct
Related
<Block ID="Ar0010100" BOX="185 211 825 278" ELEMENT_TYPE="h1" SEQ_NO="0" />
This is an example from my XML code. In C# I need to store ONLY ID'S inside of a block element in one variable, and ONLY Box's inside of a block element. I have been trying to do this for two days, and I don't know how to narrow down my question.
XmlNodeList idList = doc.SelectNodes("/Block/ID");
doesn't work... Any version of doc.selectnode, doc.GetElementBy... doesn't return the right element/children/whatever you call it. I'm not able to find documentation that tells me what I'm trying to reference. i don't know if ID or BOX are children, if they're attributes or what. This is my first time using XML, and I can't seem to narrow down my problem.
You can simply use following code
XmlNodeList elemList = doc.GetElementsByTagName("Your Element");
for (int i = 0; i < elemList.Count; i++)
{
string attrVal = elemList[i].Attributes["ID"].Value;
}
Demo: https://dotnetfiddle.net/5PpNPk
the above code is taken from here Read XML Attribute using XmlDocument
The problem is that ID is actually neither child nor part.
It's a node's attribute. You can access it this way:
doc.SelectSingleNode("/Block").GetAttribute("ID")
// or
doc.SelectSingleNode("/Block").Attributes["ID"].Value
Of course, you can iterate through them:
foreach (XmlElement element in doc.SelectNodes("/Block"))
{
Console.WriteLine(element.GetAttribute("ID"));
}
You also can ensure that it contains ID attribute, so, you won't get NullReferenceException or other exception. Use the following XPath:
foreach (XmlElement element in doc.SelectNodes("/Block[#ID]"))
{
Console.WriteLine(element.GetAttribute("ID"));
}
Your attempted xpath tried to find <Block> element having child element <ID>. In xpath, you use # at the beginning of attribute name to reference an attribute, for example /Block/#ID.
Given a correct xpath expression as parameter, SelectNodes() and SelectSingleNode() are capable of returning attributes. Here is an example :
var xml = #"<Block ID=""Ar0010100"" BOX=""185 211 825 278"" ELEMENT_TYPE=""h1"" SEQ_NO=""0"" />";
var doc = new XmlDocument();
doc.LoadXml(xml);
XmlNodeList idList = doc.SelectNodes("/Block/#ID");
foreach(XmlNode id in idList)
{
Console.WriteLine(id.Value);
}
Demo
I have the below XML and I've been trying to extract the FirstName, LastName and OtherName for a while now I'm running into all sort of problems.
<OmdCds xmlns="cds"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:cdsd="cds_dt"
xsi:schemaLocation="cds ontariomd_cds.xsd">
<PatientRecord>
<Demographics>
<Names>
<cdsd:LegalName namePurpose="L">
<cdsd:FirstName>
<cdsd:Part>SARAH</cdsd:Part>
<cdsd:PartType>GIV</cdsd:PartType>
<cdsd:PartQualifier>BR</cdsd:PartQualifier>
</cdsd:FirstName>
<cdsd:LastName>
<cdsd:Part>GOMEZ</cdsd:Part>
<cdsd:PartType>FAMC</cdsd:PartType>
<cdsd:PartQualifier>BR</cdsd:PartQualifier>
</cdsd:LastName>
<cdsd:OtherName>
<cdsd:Part>GABRIELA</cdsd:Part>
<cdsd:PartType>GIV</cdsd:PartType>
<cdsd:PartQualifier>BR</PartQualifier>
I currently trying to extract with the below c# code but still can't extract the above data. I'm getting a nullreferenceexception.
XmlDocument doc = new XmlDocument();
doc.Load(folder + "\\" + o.ToString());
XmlNamespaceManager namespaceManager = new XmlNamespaceManager(doc.NameTable);
namespaceManager.AddNamespace("cdsd", "http://www.w3.org/2001/XMLSchema-instance");
XmlNode firstName = doc.DocumentElement.SelectSingleNode("/PatientRecord/Demographics/Names/cdsd:LegalName/cdsd:FirstName/cdsd:Part", namespaceManager);
string fName = firstName.InnerText;
MessageBox.Show(fName);
I can see in the local watch item under doc.DocumentElement, all the InnerXML and InnerText. The InnerXML look something like this...
<PatientRecord xmlns=\"cds\"><Demographics><Names><cdsd:LegalName namePurpose=\"L\" xmlns:cdsd=\"cds_dt\"><cdsd:FirstName><cdsd:Part>SARAH</cdsd:Part><cdsd:PartType>GIV</cdsd:PartType><cdsd:PartQualifier>BR</cdsd:PartQualifier></cdsd:FirstName>
You have 3 namespace definitions in the document:
cds - as a default namespace
http://www.w3.org/2001/XMLSchema-instance- with the xsi prefix
cds_dt - with the cdsd prefix
I am wondering that you don't get an error message, because cds and cds_dt are no URIs and namspaces need to be URIs.
If you try to understand an element name you need to replaces the prefix with the actual namespace.
<PatientRecord> reads as {cds}:PatientRecord
<cdsd:LegalName> reads as {cds_dt}:LegalName
Now in XPath 1.0 the same happens with registered namespaces. But XPath does not have a default namespace. So elements without one are not expanded with a default namespace.
You need to register namespace prefixes on the namespace manager. The prefix does not need to be the same as in the document.
namespaceManager.AddNamespace("cdsd", "cds_dt");
namespaceManager.AddNamespace("cds", "cds");
Now you can use the registered namespaces in XPath:
doc.DocumentElement.SelectSingleNode(
"cds:PatientRecord/cds:Demographics/cds:Names/cdsd:LegalName/cdsd:FirstName/cdsd:Part",
namespaceManager
);
If the first character of an XPath expression is a slash the expression is relative to the document, otherwise to the current context node. You call SelectSingleNode() on the doc.DocumentElement - the OmdCds element node. PatientRecord is a child node, so you can start with it or use . for the current context node.
PatientRecord, Demographics and Names are in the cds namespace. This is because of the default namespace declaration on the OmdCds element (xmlns="cds"). The others are in the cdsd namespace, not xsi. You'll have to add them and use them in the XPATH:
namespaceManager.AddNamespace("cdsd", "cdsd");
namespaceManager.AddNamespace("cds", "cds");
XmlNode firstName = doc.DocumentElement.SelectSingleNode(
"/cds:PatientRecord/cds:Demographics/cds:Names/cdsd:LegalName/cdsd:FirstName/cdsd:Part",
namespaceManager);
BTW, you're getting a NullReferenceException because you're making the false assumption that your query will always return a node. You are now seeing what happens when it does not return a node. Always check for null whenever it's possible that a query returns no value.
Instead XmlDocument class you can use Linq to XML, is easy. You need using the System.Xml.Linq namspace, for example:
XDocument xdoc = XDocument.Load("path");
IEnumerable<XElement> nodes = (from p in xdoc.Descendants()
where p.Name.LocalName == "FirstName"
select p).Elements();
foreach (XElement nodeFirstName in nodes)
{
foreach (XElement parts in nodeFirstName.Elements())
{
string strExtracted = parts.Name.LocalName + " " + parts.Value;
}
}
The LocalName property is used beacuse elements have a prefix "cdsd"
Considering the following XML:
<Stations>
<Station>
<Code>HT</Code>
<Type>123</Type>
<Names>
<Short>H'bosch</Short>
<Middle>Den Bosch</Middle>
<Long>'s-Hertogenbosch</Long>
</Names>
<Country>NL</Country>
</Station>
</Stations>
There are multiple nodes. I need the value of each node.
I've got the XML from a webpage (http://webservices.ns.nl/ns-api-stations-v2)
Login (--) Pass (--)
Currently i take the XML as a string and parse it to a XDocument.
var xml = XDocument.Parse(xmlString);
foreach (var e in xml.Elements("Long"))
{
var stationName = e.ToString();
}
You can retrieve "Station" nodes using XPath, then get each subsequent child node using more XPath. This example isn't using Linq, which it looks like you possibly are trying to do from your question, but here it is:
XmlDocument xml = new XmlDocument();
xml.Load(xmlStream);
XmlNodeList stations = xml.SelectNodes("//Station");
foreach (XmlNode station in stations)
{
var code = station.SelectSingleNode("Code").InnerXml;
var type = station.SelectSingleNode("Type").InnerXml;
var longName = station.SelectSingleNode("Names/Long").InnerXml;
var blah = "you should get the point by now";
}
NOTE: If your xmlStream variable is a String, rather than a Stream, use xml.LoadXml(xmlStream); for line 2, instead of xml.Load(xmlStream). If this is the case, I would also encourage you to name your variable to be more accurately descriptive of the object you're working with (aka. xmlString).
This will give you all the values of "Long" for every Station element.
var xml = XDocument.Parse(xmlStream);
var longStationNames = xml.Elements("Long").Select(e => e.Value);
I am parsing an URI for query_id. I want to get the last query's id. That is actually the last added node in the URI.
I am using the following code but it is failing to return the last node but is returning info from the first node. HELP !!!
XmlDocument doc = new XmlDocument();
doc.Load("helpdesk.hujelabs.com/user.php/1/query");
XmlNode node = doc.DocumentElement;
XmlNode id = node.LastChild.SelectSingleNode("//queries/query/description/text()");
string TID = id.InnerText;
Any answer of the form:
//queries/query[position() = last()]/query_id/text()
or
//queries/query/description[last()]/text()
is wrong.
It is a FAQ: The XPath // pseudo-operator has lower precedence then the [] operator -- this is why the above expressions select any query (or respectively description) element that is the last child of its parent -- these can be all query or description elements.
Solution:
Use:
(//queries/query)[last()]/query_id/text()
Also note: The use of the // pseudo-operator usually results in signifficant loss of efficiency, because this causes the whole (sub) tree rooted at the current node to be completely traversed (O(N^2) operation).
A golden rule: Whenever the structure of the XML document is statically (in advance) known and stable, never use //. Instead use an XPath expression that has a series of specific location steps.
For example, if all the elements you want to select can be selected using:
/x/y/queries/query
then use the above XPath expression -- not //queries/query
use this XPath
//queries/query/description[last()]/text()
To retrieve last query's query_id, change your XPath to
/queries/query[position() = last()]/query_id/text()
Or alternatively, use LINQ to XML:
var doc = XDocument.Load("http://helpdesk.hujelabs.com/user.php/1/query");
var elem = doc.Root.Elements("query").Last().Element("query_id");
var TID = (int)elem;
I have code which parses XML that looks like this:
<custom_fields>
<custom_field>
<column_name>foo</column_name>
<column_value>0</column_value>
<description>Submitted</description>
<data_type>BOOLEAN</data_type>
<length>0</length>
<decimal>0</decimal>
</custom_field>
<custom_field>
<column_name>bar</column_name>
<column_value>0</column_value>
<description>Validated</description>
<data_type>BOOLEAN</data_type>
<length>0</length>
<decimal>0</decimal>
</custom_field>
</custom_fields>
... more <custom_field> elements...
I want to find the element called custom_field which has a child element called column_name with a certain value (for example bar), and then find that child's sibling called column_value and get its value. Right now I use XPath on an XMlDocument to do this:
string path = "//custom_fields/custom_field[column_name='" + key + "']";
XmlNode xNode = doc.SelectSingleNode(path);
if (xNode != null)
{
XmlNode v = xNode.SelectSingleNode("column_value");
val.SetValue(v.InnerText);
}
Where key is the name of the field I am looking for.
But I want to do this using the new LINQ to XML syntax on an XDocument. My thinking is that I will move much of my old-style XPath parsing to the LINQ methods. Maybe it's not a good idea, but this is a case where if I can get it to work, then I believe I will have a much better understanding of LINQ in general, and will be able to clean up a lot of complex code.
You can always use XPath within LINQ to XML. Just include the System.Xml.XPath namespace.
var xpath = $"//custom_fields/custom_field[column_name='{key}']/column_value";
var columnValue = doc.XPathSelectElement(xpath);
if (columnValue != null)
{
val.SetValue((int)columnValue);
}
Otherwise for the equivalent LINQ to XML query:
var columnValue = doc.Descendants("custom_fields")
.Elements("custom_field")
.Where(cf => (string)cf.Element("column_name") == key) // assuming `key` is a string
.Elements("column_value")
.SingleOrDefault();
Your XQuery expression
//custom_fields/custom_field[column_name='key']
selects all custom_field elements in custom_fields elements where the value of the column_key child element equals "key". You expect a single element to be returned and select the value of the column_value child element.
You can express this using LINQ to XML as follows:
var doc = XDocument.Load(...);
var query = from fields in doc.Descendants("custom_fields")
from field in fields.Elements("custom_field")
where (string)field.Element("column_name") == "key"
select (int)field.Element("column_value");
int result = query.Single();
I want to find the element called
custom_field which has a child element
called column_name with a certain
value (for example "bar", and then
find that child's sibling called
column_value and get its value.
Use:
/custom_fields/custom_field[column_name = 'bar']/column_value