Problem in reading XML node with unknown root/parent nodes - c#

I have been trying to read an xml file. I have to extract value of nodes "Date" and "Name", but the problem is, they might appear at any level in XML hierarchy.
So when I try with this code,
XmlDocument doc = new XmlDocument();
doc.Load("test1.xml");
XmlElement root = doc.DocumentElement;
XmlNodeList nodes = root.SelectNodes("//*");
string date;
string name;
foreach (XmlNode node in nodes)
{
date = node["date"].InnerText;
name = node["name"].InnerText;
}
and the XML file is ::
<?xml version="1.0" encoding="utf-8"?>
<root>
<child>
<name>Aravind</name>
<date>12/03/2000</date>
</child>
</root>
the above code errors out, as <name> and <date> are not immediate child Elements of root.
is it possible to assume that parent/root nodes are unknown and just with the name of the nodes, copy the values ??

Depending on the exception you are getting, this may or may not be the exact solution. However, I would definitely check that date and name exist before doing a .InnerText on them.
foreach (XmlNode node in nodes)
{
dateNode = node["date"];
if(dateNode != null)
date = dateNode.InnerText;
// etc.
}

I would read up on XPATH and XPATH for C# to do this more efficiently
http://support.microsoft.com/kb/308333
http://www.w3schools.com/XPath/xpath_syntax.asp
Here's a little method that should allow you to get the innerText easily.
function string GetElementText(string xml, string node)
{
XPathDocument doc = new XPathDocument(xml);
XPathNavigator nav = doc.CreateNavigator();
XPathExpression expr = nav.Compile("//" + node);
XPathNodeIterator iterator = nav.Select(expr);
while (iterator.MoveNext())
{
// return 1st but there could be more
return iterator.Current.Value;
}
}

Try to use LINQ:
string xml = #"<?xml version='1.0' encoding='utf-8'?>
<root>
<date>12/03/2001</date>
<child>
<name>Aravind</name>
<date>12/03/2000</date>
</child>
<name>AS-CII</name>
</root>";
XDocument doc = XDocument.Parse(xml);
foreach (var date in doc.Descendants("date"))
{
Console.WriteLine(date.Value);
}
foreach (var date in doc.Descendants("name"))
{
Console.WriteLine(date.Value);
}
Console.ReadLine();
The Descendants method allows you to get all the elements that have a specified name.

Related

Reading XML file results in index out of range exception

Using C# I have an XML file like
<?xml version="1.0" encoding="utf-8"?>
<root>
<Account>
<name>Jani</name>
</Account>
</root>
and I also have a function to read the name node as:
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load("lib//user.xml");
XmlNode node;
node = xmlDoc.DocumentElement;
string name = node.Attributes[0].Value;
label1.Text = name.ToString();
but I am getting index out of range error as:
Why is this happening?
node = xmlDoc.DocumentElement;
string name = node.Attributes[0].Value;
node is your root node. Which looks like this:
<root>
How many attributes does it have? None, as it turns out. An attribute in XML is one of these bar="baz" things:
<foo bar="baz">
node.Attributes[0] refers to the first attribute. There is no first attribute, there's no second attribute -- you didn't use attributes in this XML at all. Hence, that's out of range. There's no first item in an empty collection.
What you want is an element named name, which is farther down inside your XML tree.
Probably this:
var node = xmlDoc.DocumentElement.SelectSingleNode("/root/Account/name");
And then you'll want to look at node.InnerText to get "Jani" out of it.
You are trying to read node.Attributes[0].Value but there is no attribtues in your sample XML file. Not sure of the exact syntax but it should probably be closer to node.Value
As mentioned by other answers, your current XML does not have attributes.
private void DoIt()
{
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(#"M:\StackOverflowQuestionsAndAnswers\38924171\38924171\data.xml");
XmlNode node;
node = xmlDoc.DocumentElement;
//string name = node.Attributes[0].Value;
string name = node["Account"].InnerText;
}
If your XML did have attributes
<?xml version="1.0" encoding="utf-8"?>
<root>
<Account name="Jani" />
</root>
Then you could do this:
private void DoItAgain()
{
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(#"M:\StackOverflowQuestionsAndAnswers\38924171\38924171\data2.xml");
XmlNode node;
node = xmlDoc.DocumentElement;
string name = node["Account"].Attributes[0].Value;
}

Working With Specific XML structure

I am trying to get some data from an XML document. I have no control over the schema. If it were up to me I would have chosen another schema. I am using C#'s XPATH library to get the data.
XML DOC
<Journals>
<name>Title of Journal</name>
<totalvolume>2</totalvolume>
<JournalList>
<Volume no="1">
<Journal>
<issue>01</issue>
<Title>Title 1</Title>
<date>1997-03-10</date>
<link>www.somelink.com</link>
</Journal>
<Journal>
<issue>02</issue>
<Title>Title 3</Title>
<date>1997-03-17</date>
<link>www.somelink.com</link>
</Journal>
</Volume>
<Volume no="2">
<Journal>
<issue>01</issue>
<Title>Title 1</Title>
<date>1999-01-01</date>
<link>www.somelink.com</link>
</Journal>
<Journal>
<issue>01</issue>
<Title>Title 2</Title>
<date>1999-01-08</date>
<link>www.somelink.com</link>
</Journal>
</Volume>
</JournalList>
</Journals>
I am trying to get all the data in the Volume 2 node. Here is what I tried so far:
C# Code:
protected void loadXML(string url)
{
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(url);
string strQuery = "Volume[#no='2']";
XmlElement nodeList = xmlDoc.DocumentElement;
XmlNodeList JournalList = nodeList.SelectNodes(strQuery);
foreach (XmlElement Journal in JournalList)
{
XmlElement temp = Journal;
}
}
It seems there are no nodes in JournalList. Anyone? Thanks in advance/
Your code is looking for "Volume" nodes directly under the "Journals" node
Change this:
string strQuery = "Volume[#no='2']";
To this, in order to look for "Volume" nodes under the "JournalList" node:
string strQuery = "JournalList/Volume[#no='2']";
Also, there's a couple typos in your XML:
</Volume no="2"> -> <Volume no="2"> // no open tag found
</Journal> -> </Journals> // expecting end tag </Journals>
From your comment below:
how would I go about access each journal? for example. I want irrate through each "journal" and get the title of the journal?
In order to do that, you could modify your code slightly:
var nodeList = xmlDoc.DocumentElement;
var volume = nodeList.SelectSingleNode(strQuery);
foreach (XmlElement journal in volume.SelectNodes("Journal"))
{
var title = journal.GetElementsByTagName("Title")[0].InnerText;
}
Also you can use Linq to XML:
using System.Xml.Linq;
//...
string path="Path of your xml file"
XDocument doc = XDocument.Load(path);
var volume2= doc.Descendants("Volume").FirstOrDefault(e => e.Attribute("no").Value == "2");

C# how to create a custom xml document

I'm really just trying to create a custom xml document for simple configuration processing.
XmlDocument xDoc = new XmlDocument();
string[] NodeArray = { "Fruits|Fruit", "Vegetables|Veggie"};
foreach (string node in NodeArray)
{
XmlNode xmlNode = xDoc.CreateNode(XmlNodeType.Element,node.Split('|')[0],null);
//xmlNode.Value = node.Split('|')[0];
xmlNode.InnerText = node.Split('|')[1];
xDoc.DocumentElement.AppendChild(xmlNode);
}
What i'm trying to get is this.
<?xml version="1.0" encoding="ISO-8859-1"?>
<Fruits>Fruit</Fruits>
<Vegetables>Veggie</Vegetables>
i get not set to value of an object at xDoc.DocumentElement.AppendChild(xmlNode);
Unfortunately, You can't make that XML structure.
All XML documents must have a single root node. You can't have more.
Try something like this
XmlDocument xDoc = new XmlDocument();
xDoc.AppendChild( xDoc.CreateElement("root"));
string[] NodeArray = { "Fruits|Fruit", "Vegetables|Veggie" };
foreach (string node in NodeArray)
{
XmlNode xmlNode = xDoc.CreateNode(XmlNodeType.Element, node.Split('|')[0], null);
//xmlNode.Value = node.Split('|')[0];
xmlNode.InnerText = node.Split('|')[1];
xDoc.DocumentElement.AppendChild(xmlNode);
}
It is not possible to have that XML structure as XML MUST have a single root element. You may want to try:
<?xml version="1.0" encoding="ISO-8859-1"?>
<items>
<Fruits>Fruit</Fruits>
<Vegetables>Veggie</Vegetables>
</items>

Algorithm for xml document splitting

I want to split an xml document into several xml documents by specified node name, (similar with string.Split(...).)
Example: I have the following xml document.
<root>
<nodeA>
Hello
</nodeA>
<nodeA>
<nodeB>
node b Text
</nodeB>
<nodeImage>
image.jpg
</nodeImage>
</nodeA>
<nodeA>
node a text
</nodeA>
</root>
I want to split this xml document into 3 parts by 'nodeImage', and keep the original xml structure. (Note: the node with name 'nodeImage' could be anywhere)
1. xml before nodeImage
2. xml for nodeImage
3. xml after nodeImage
For the sample xml, the results should be:
XML Document 1:
<root>
<nodeA>
Hello
</nodeA>
<nodeA>
<nodeB>
node b Text
</nodeB>
</nodeA>
</root>
XML Document 2:
<root>
<nodeA>
<nodeImage>
image.jpg
</nodeImage>
</nodeA>
</root>
XML Document 3:
<root>
<nodeA>
node a text
</nodeA>
</root>
Does anyone know if there is a good algorithm, or existing code sample for this requirement?
Update Notes:
If there is only one node with the name 'nodeImage' in the xml document, then this xml document should always be splitted into 3 xml documents.
XElement xe = XElement.Load(XMLFile);
foreach(XElement newXE in xe.Elements("nodeA"))
{
XElement root = new XElement("root",newXE);
root.Save(newFile);
}
The term "split" is slightly confusing. Splitting on one ocurrence does not usually produce three parts.
I start by trying to define your question in Linq to xml terms.
For every occurrence of XDocument.Descendants("nodeImage") you want to create:
A copy of the document where the nodeImage parent has the nodeImage and all succeeding nodes removed. In addition all ancestors must have all nextnodes removed.
A copy of the document where all ancestors of the nodeImage element have all XElement.NextNodes and XElement.PreviousNodes removed.
Running this check again on a copy of the XDocument where all Ancestor PreviousNodes have been removed.
If no occurrence is found. The document being checked is returned in its entirety.
A deep copy of XDocument is easy. It has a copy constructor.
Of course, this will be a hog on memory if your xml is of a significant size.
However, the challenge is to locate your node in every copy.
This question shows how you can get the XPath of an element. You can use that.
This works. Test it extensively.
var doc = new XmlDocument();
doc.LoadXml(#"<root>
<nodeA>
Hello
</nodeA>
<nodeA>
<nodeB>
node b Text
</nodeB>
<nodeImage>
image.jpg
</nodeImage>
</nodeA>
<nodeA>
node a text
</nodeA></root>");
var xmlFrags = new List<string>();
string xml = "<root>";
bool bNewFragment = true;
foreach (XmlNode nodeA in doc.SelectNodes("//root/nodeA")) {
XmlNode nodeImage = nodeA.SelectSingleNode("nodeImage");
if (nodeImage != null) {
xml += "<nodeA>";
var en = nodeA.GetEnumerator();
while (en.MoveNext()) {
XmlNode xn = (XmlNode)en.Current;
if (xn != nodeImage)
xml += xn.OuterXml;
}
xml += "</nodeA></root>";
xmlFrags.Add(xml);
xml = "<root><nodeA>" + nodeImage.OuterXml + "</nodeA></root>";
xmlFrags.Add(xml);
bNewFragment = true;
}
else
{
if (bNewFragment) {
xml = "<root>";
bNewFragment = false;
}
xml += nodeA.OuterXml;
}
}
if (!bNewFragment) {
xml += "</root>";
xmlFrags.Add(xml);
}
//Use the XML fragments as you like
foreach (var xmlFrag in xmlFrags)
Console.WriteLine(xmlFrag + Environment.NewLine);
something like this, using System.Xml.Linq?
var doc = XDocument.Parse(stringxml);
var res = new List<XElement>();
var cur = new XElement("root");
foreach (var node in doc.Element("root").Elements("nodeA"))
{
if (node.Element("nodeImage") == null)
{
cur.Add(node);
}
else
{
res.Add(cur);
res.Add(new XElement("root", node));
cur = new XElement("root");
}
}
res.Add(cur);
Try this:
using System;
using System.Xml;
class Program
{
static void Main(string[] args)
{
// create the XML documents
XmlDocument
doc1 = new XmlDocument(),
doc2 = new XmlDocument(),
doc3 = new XmlDocument();
// load the initial XMl into doc1
doc1.Load("input.xml");
// create the structure of doc2 and doc3
doc2.AppendChild(doc2.ImportNode(doc1.FirstChild, false));
doc3.AppendChild(doc3.ImportNode(doc1.FirstChild, false));
doc2.AppendChild(doc2.ImportNode(doc1.DocumentElement, false));
doc3.AppendChild(doc3.ImportNode(doc1.DocumentElement, false));
// select the nodeImage
var nodeImage = doc1.SelectSingleNode("//nodeImage");
if (nodeImage != null)
{
// append to doc3
var node3 = nodeImage.ParentNode.NextSibling;
var n3 = doc3.ImportNode(node3, true);
doc3.DocumentElement.AppendChild(n3);
// append to doc2
var n2 = doc2.ImportNode(nodeImage.ParentNode, true);
n2.RemoveChild(n2.SelectSingleNode("//nodeImage").PreviousSibling);
doc2.DocumentElement.AppendChild(n2);
// remove from doc1
nodeImage.ParentNode.ParentNode
.RemoveChild(nodeImage.ParentNode.NextSibling);
nodeImage.ParentNode
.RemoveChild(nodeImage);
}
Console.WriteLine(doc1.InnerXml);
Console.WriteLine(doc2.InnerXml);
Console.WriteLine(doc3.InnerXml);
}
}

How to get element value using c#

XML file:
<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<content>
<FingerPrintUserDetails>
<UserID>e57645</UserID>
<UserName>Jill</UserName>
<FPData>AQAAABQAAAD0AAAAAQASAAEAWgAAAAAA8AAAAHfrWpB6BHZBL10voxpdxu2Km5XVNh*oUNC80Rvpql3RhlqOiBPeet6iRPwb/BdN1fCF4Y/WHbQ40*mqoUKqilgN7bUqNuXP7M299HUWtoAGEO3nDKXXAnHd7dgytZbmHVv*mRBPJDSRw9VY/R1yOIu2cCDlLM*F8Q1lvTfMFDdfwNZynI0e2ZauCF58f0UX56XLFBallaAauxP5mvvhUmcmc6ITg7RhH9wc4181kgPjCuZg38pQepE5U07XIa3hQP8fwxPzdprifXECgB1Z3pTXWQP0q4ZD0Inlbq6Gszo1ucPrhQA0jYQRXtJUVuyBeg</FPData>
<Address>Pune</Address>
<ContactNo>848488484884</ContactNo>
</FingerPrintUserDetails>
<FingerPrintUserDetails>
<UserID>444</UserID>
<UserName>John</UserName>
<FPData>AQAAABQAAADkAAAAAQASAAEAZAAAAAAA4AAAAPLnmQ8FymAAHWYutR5pdtYvfDVmjsqLeli8tOSTFAtw6AkfA0r8XwrMzp9jFZJI7DlBk4G94BMq55gPEG7uBLZUNYrvhv0jDlDFMOjWGJ9RoWekFveTC*oZ7Tq/xmxuvY6FzLHVo*xzdKQI73Y0f9/eeMC0OgqnbQ3I0IP6cTkkKnTUZJOXKr7IFPHkjJAvCDmU7ec4vG50JHdBJIObmbzVcO0huTUQyE7CR1qYkUjmNFKgVKWPLRupEk4l/Ek0BuAba*9JlhBVUHzZuKbDQLc9lTFwevAgDuuAwxfZaLS*</FPData>
<Address>nagpur</Address>
<ContactNo>464645763</ContactNo>
</FingerPrintUserDetails>
<FingerPrintUserDetails>
<UserID>5555</UserID>
<UserName>Jack</UserName>
<FPData>AQAAABQAAAAEAQAAAQASAAEAZAAAAAAA9AAAAPz5mQO3uTeXLfU5Mb74XbCX5rERGZFPQMVG1vPpX87306O5oURlYiIe5dasJ2S8NlBZu2UU3zaUpNnB7viYDB6*wfFlgtopn/WdbXW0Yhik3hj8nDreEmaK12To8qfAJx2ooq43i0wBIL*0Jkba*QpHIprSajrhnCg1PjOLMP37sEauJUwXJaoDR/PPQYIxTFE5kf8xzGlJmqiGejD*Y8R3ewU9yIrxkdQ0S//LCdacULt2QvS/I3APo/j0FAgSCOU3SBLdDL6UBPD4fLeEzo7uUIW8gUMThzZX*u2iUuNwJdqWC2NsFtWkUWt03sz3xYQpR8pLA4vrsUmldzUMWe8</FPData>
<Address>beed</Address>
<ContactNo>5745745747</ContactNo>
</FingerPrintUserDetails>
</content>
C#:
XmlDocument doc = new XmlDocument();
doc.Load("E://BioEnable_Project//fp_project_using_xml//fp_project_using_xml//Capture_Data.xml");
XmlElement root = doc.DocumentElement;
XmlNodeList nodes = root.SelectNodes("FPData");
foreach(XmlElement node in nodes)
{
MessageBox.Show(node.Value);
}
I have to check FPData value on each node..i use above code but not getting..
In your XPath, provide the full path to the node.
XmlNodeList nodes = root.SelectNodes("/content/FingerPrintUserDetails/FPData");
What is happening is that there is no direct FPData node under the document root.
XmlNodeList nodes = root.SelectNodes("content/FingerPrintUserDetails");
it will return array of FingerPrintUserDetails, then find FPData in them
XmlNodeList res = nodes[index].SelectNodes("FPData");
Using LINQ to XML:
XDocument doc = XDocument.Load("XmlFilePath");
var selectors = from elements in doc.Elements("content").Elements("FingerPrintUserDetails")
select elements;
foreach (var element in selectors)
{
MessageBox.Show(element.Element("FPData").Value);
}
XmlDocument doc = new XmlDocument();
doc.Load("E://BioEnable_Project//fp_project_using_xml//fp_project_using_xml//Capture_Data.xml");
XmlNodeList lst = doc.GetElementsByTagName("FingerPrintUserDetails");
foreach (XmlElement elem in lst)
{
XmlNode pfData = doc.GetElementsByTagName("FPData")[0];
MessageBox.Show(pfData.Value);
}

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