Develop Reference

C# xml reader, same element name

I'm trying to read an element from my xml file.
I need to read an string in an "link" element inside the "metadata",
but there are 2 elements called "link", I only need the second one:
<metadata>
<name>visit-2015-02-18.gpx</name>
<desc>February 18, 2015. Corn</desc>
<author>
<name>text</name>
<link href="http://snow.traceup.com/me?id=397760"/>
</author>
<link href="http://snow.traceup.com/stats/u?uId=397760&vId=1196854"/>
<keywords>Trace, text</keywords>
I need to read this line:
<link href="http://snow.traceup.com/stats/u?uId=397760&vId=1196854"/>
This is the working code for the first "link" tag, it works fine,
public string GetID(string path)
{
string id = "";
XmlReader reader = XmlReader.Create(path);
while (reader.Read())
{
if ((reader.NodeType == XmlNodeType.Element) && (reader.Name == "link"))
{
if (reader.HasAttributes)
{
id = reader.GetAttribute("href");
MessageBox.Show(id + "= first id");
return id;
//id = reader.ReadElementContentAsString();
}
}
}
return id;
}
Does anyone know how I can skip the first "link" element?
or check if reader.ReadElementContentAsString() contains "Vid" or something like that?
I hope you can help me.

xpath is the answer :)
XmlReader reader = XmlReader.Create(path);
XmlDocument doc = new XmlDocument();
doc.Load(reader);
XmlNodeList nodes = doc.SelectNodes("metadata/link");
foreach(XmlNode node in nodes)
Console.WriteLine(node.Attributes["href"].Value);

Use the String.Contains method to check if the string contains the desired substring, in this case vId:
public string GetID(string path)
{
XmlReader reader = XmlReader.Create(path);
while (reader.Read())
{
if ((reader.NodeType == XmlNodeType.Element) && (reader.Name == "link"))
{
if (reader.HasAttributes)
{
var id = reader.GetAttribute("href");
if (id.Contains(#"&vId"))
{
MessageBox.Show(id + "= correct id");
return id;
}
}
}
return String.Empty;
}
If acceptable you can also use LINQ2XML:
var reader = XDocument.Load(path); // or XDocument.Parse(path);
// take the outer link
Console.WriteLine(reader.Root.Element("link").Attribute("href").Value);
The output is always:
http://snow.traceup.com/stats/u?uId=397760&vId=1196854= first id
Another options is to use XPath like #user5507337 suggested.

XDocument example:
var xml = XDocument.Load(path); //assuming path points to file
var nodes = xml.Root.Elements("link");
foreach(var node in nodes)
{
var href = node.Attribute("href").Value;
}

Locate nodes in XML file

I have fixed my issue with reading the XML files. What I am needing now is to trim the datetime down to just MM dd yyyy hh:mm:ss and not bring the rest of it over when I insert into my Informix database.
This is the XML info:
<RecordFilingRequestMessage xmlns:nc="http://niem.gov/niem/niem-core/2.0">
<nc:DocumentIdentification>
<nc:IdentificationID>3212842</nc:IdentificationID>
</nc:DocumentIdentification>
<nc:DocumentPostDate>
<nc:DateTime>2013-06-25T11:32:08.5343733-04:00</nc:DateTime>
</nc:DocumentPostDate>
<nc:DocumentSubmitter>
<ecf:EntityPerson s:id="REVIEWER">
<nc:PersonName />
<nc:PersonOtherIdentification>
<nc:IdentificationID>41130</nc:IdentificationID>
<nc:IdentificationCategoryText>FLEPORTAL</nc:IdentificationCategoryText>
</nc:PersonOtherIdentification>
<nc:PersonOtherIdentification>
<nc:IdentificationID>kacolburn</nc:IdentificationID>
<nc:IdentificationCategoryText>FLEPORTAL_LOGONNAME</nc:IdentificationCategoryText>
</nc:PersonOtherIdentification>
...and here is my C# code:
string DocID = null;
int elementCount = 0;
string reqID = null;
string reqDateTime = null;
string empName = null;
string[] fileEntries = Directory.GetFiles(#"C:\XML\3212842.xml");
foreach (string fileName in fileEntries)
{
XmlReader xr = XmlReader.Create(fileName); //reads XML from folder
while (xr.Read())
{
if (xr.NodeType == XmlNodeType.Element && xr.Name == "nc:DateTime")
{
reqDateTime = xr.ReadElementContentAsString();
}
if (xr.NodeType == XmlNodeType.Element && xr.Name == "nc:IdentificationID")
{
elementCount++;
DocID = xr.ReadElementContentAsString();
if (elementCount == 1)
{
reqID = DocID;
}
if (elementCount == 3)
{
empName = DocID;
listBox1.Items.Add(reqID + " / " + reqDateTime + " / " + empName);
elementCount = 0;
break;
}

My first thought is, that the last '/' doesn't belong to the 'SelectNodes' call.
Alternatively, this code will solve your problem:
foreach(XmlNode node in xmlDoc.GetElementsByTagName("RecordFilingRequest")[0].GetElementsByTagName("nc:DocumentIdentification"))
{
int ID = Convert.ToInt32(node.FirstChild().InnerText);
}
Edit: This does assume, that 'RecordFilingRequest' always exists. Add a try .. catch statement, if that isn't the case.

Looks like the issue is that the XML uses namespaces, and your XPath does not. You didn't post your full XML, but you probably have something like xmlns:nc="http://some.url/ in there. Make sure to include a the namespace in a namespace manager, then add namespace prefixes to your query:
var nameTable = new NameTable();
var nsMgr = new XmlNamespaceManager(nameTable);
nsmgr.AddNamespace("nc", "http://some.url/");
var dataNodes = xmlDoc.SelectNodes("nc:RecordFilingRequest/nc:DocumentIdentification", nsMgr);
foreach (var node in dataNodes)
{
var ID = Convert.ToInt32(node.SelectSingleNode("nc:IdentificationID", nsMgr).InnerText);
// insert into database, e.g. using SqlCommand or whatever
}

read only particular instance using xmlreader

I have a xml file that looks like
<Name>AAA</Name>
<Age>23</Age>
<I1>
<Element1>A</Element1>
<Element2>B</Element2>
<Element3>C</Element3>
<\I1>
<I2>
<Element1>AA</Element1>
<Element2>BB</Element2>
<Element3>CC</Element3>
</I2>
I am reading all the values of elements using xmlreader in C# 3.0. But now i have to change by reading only the values within particular start and end tage. For the xml file mentioned above, i need to read <Name>, <Age> by default and then i have a function that returns the value "I1" or "I2" which is basically the element names. If it returns "I1" then i should read only the elements between <I1> and </I1> and should not read <I2> and vice versa. So the code structure would be (just the logic please ignore the syntax errors) like
/******function that returns element name I1 or I2*********/
string elementName = func(a,b);
xmlreader reader = reader.create("test.xml");
while(reader.read())
{
switch(reader.nodetype)
{
case xmlnodetype.element:
string nodeName = reader.name
break;
case xmlnodetype.text
switch(nodeName)
{
/*************Read default name and age values*******/
case "Name":
string personName = reader.value
break;
case "Age":
string personAge = reader.value;
break;
/*******End of reading default values**************/
/*** read only elements between the value returned by function name above
If function returns I1 then i need to read only values between <I1> </I1> else read </I2> and </I2>**/
}
}
}
Thanks!

So assuming, since we dont have any other tags to go off, that your file would look something such as this from beginning to end
<?xml version="1.0" encoding="utf-8" ?>
<RootElement>
<UserInformation>
<Name>AAA</Name>
<Age>23</Age>
<I1>
<Element1>A</Element1>
<Element2>B</Element2>
<Element3>C</Element3>
<\I1>
<I2>
<Element1>AA</Element1>
<Element2>BB</Element2>
<Element3>CC</Element3>
</I2>
</UserInformation>
</RootElement>
and then to call it
System.IO.StreamReader sr = new System.IO.StreamReader("test.xml");
String xmlText = sr.ReadToEnd();
sr.Close();
List<UserInfo> finalList = readXMLDoc(xmlText);
if(finalList != null)
{
//do something
}
private List<UserInfo> readXMLDoc(String fileText)
{
//create a list of Strings to hold our user information
List<UserInfo> userList = new List<UserInfo>();
try
{
//create a XmlDocument Object
XmlDocument xDoc = new XmlDocument();
//load the text of the file into the XmlDocument Object
xDoc.LoadXml(fileText);
//Create a XmlNode object to hold the root node of the XmlDocument
XmlNode rootNode = null;
//get the root element in the xml document
for (int i = 0; i < xDoc.ChildNodes.Count; i++)
{
//check to see if we hit the root element
if (xDoc.ChildNodes[i].Name == "RootElement")
{
//assign the root node
rootNode = xDoc.ChildNodes[i];
break;
}
}
//Loop through each of the child nodes of the root node
for (int j = 0; j < rootNode.ChildNodes.Count; j++)
{
//check for the UserInformation tag
if (rootNode.ChildNodes[j].Name == "UserInformation")
{
//assign the item node
XmlNode userNode = rootNode.ChildNodes[j];
//create userInfo object to hold results
UserInfo userInfo = new UserInfo();
//loop through each if the user tag's elements
foreach (XmlNode subNode in userNode.ChildNodes)
{
//check for the name tag
if (subNode.Name == "Name")
{
userInfo._name = subNode.InnerText;
}
//check for the age tag
if (subNode.Name == "Age")
{
userInfo._age = subNode.InnerText;
}
String tagToLookFor = "CallTheMethodThatReturnsTheCorrectTag";
//check for the tag
if (subNode.Name == tagToLookFor)
{
foreach (XmlNode elementNode in subNode.ChildNodes)
{
//check for the element1 tag
if (elementNode.Name == "Element1")
{
userInfo._element1 = elementNode.InnerText;
}
//check for the element2 tag
if (elementNode.Name == "Element2")
{
userInfo._element2 = elementNode.InnerText;
}
//check for the element3 tag
if (elementNode.Name == "Element3")
{
userInfo._element3 = elementNode.InnerText;
}
}
}
}
//add the userInfo to the list
userList.Add(userInfo);
}
}
}
catch (Exception e)
{
System.Windows.Forms.MessageBox.Show(e.Message);
return null;
}
//return the list
return userList;
}
//struct to hold information
struct UserInfo
{
public String _name;
public String _age;
public String _element1;
public String _element2;
public String _element3;
}

How to update the XMLDocument using c#?

I want to update the xml document and i need to return the updated xml in string. I am trying like below. when i save the document it expects the file name. but i dont want to save this as file. i just want to get the updated xml in string.
string OldXml = #"<Root>
<Childs>
<first>this is first</first>
<second>this is second </second>
</Childs
</Root>";
XmlDocument NewXml = new XmlDocument();
NewXml.LoadXml(OldXml );
XmlNode root = NewXml.DocumentElement;
XmlNodeList allnodes = root.SelectNodes("*");
foreach (XmlNode eachnode in allnodes)
{
if (eachnode.Name == "first")
{
eachnode.InnerText = "1";
}
}
NewXml.Save();
string newxml = NewXml.OuterXml;

You don't need to call Save method because string is immutable, your problem is in root.SelectNodes("*"), it just get child nodes, not all level of nodes. You need to go one more level:
foreach (XmlNode eachnode in allnodes)
{
var firstNode = eachnode.ChildNodes.Cast<XmlNode>()
.SingleOrDefault(node => node.Name == "first");
if (firstNode != null)
{
firstNode.InnerText = "1";
}
}
string newxml = NewXml.OuterXml;
It would be strongly recommended using LINQ to XML, it's simpler:
var xDoc = XDocument.Parse(OldXml);
foreach (var element in xDoc.Descendants("first"))
element.SetValue(1);
string newXml = xDoc.ToString();

Your iteration never reaches a node called "first". Else it would work fine without saving the NewXml.
You could however use a XElement and iterate over all descendants.
string OldXml = #"<Root>
<Childs>
<first>this is first</first>
<second>this is second </second>
</Childs>
</Root>";
var NewXml = XElement.Parse(OldXml);
foreach (var node in NewXml.Descendants())
{
if (node.Name.LocalName == "first")
{
node.Value = "1";
}
}
var reader = NewXml.CreateReader();
reader.MoveToContent();
string newxml = reader.ReadInnerXml();

Find all the child node of specific value in C#

<main>
<myself>
<pid>1</pid>
<name>abc</name>
</myself>
<myself>
<pid>2</pid>
<name>efg</name>
</myself>
</main>
that is my XML file named simpan. I have two button. next and previous. What i want to do is, all the info will shows off on the TextBox when the user click the button. The searching node will be based on the pid.
Next button will adding 1 value of pid (let's say pid=2) and it will search on the node that have the same value of pid=2. it also will show the name for the pid=2. (showing name=abc)
Same goes to the previous button where it will reduce 1value of pid (pid=1).
Does anybody knows how to do this?
//-------------EDIT------------------
thanks to L.B, im trying to use his code. however i got an error.
is my implementation of code correct?
private void previousList_Click(object sender, EventArgs e)
{
pid = 14;
XDocument xDoc = XDocument.Parse("C:\\Users\\HDAdmin\\Documents\\Fatty\\SliceEngine\\SliceEngine\\bin\\Debug\\simpan.xml");
var name = xDoc.Descendants("myself")
.First(m => (int)m.Element("PatientID") == pid)
.Value;
textETA.Text = name;
////////////////////
}

int pid = 2;
XDocument xDoc = XDocument.Parse(xml); //Load
var name = xDoc.Descendants("myself")
.First(m => (int)m.Element("pid") == pid)
.Element("name")
.Value;

You can use the following XPath to list all Myself tags, then look for what you want using a simple Linq command:
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(AppDomain.CurrentDomain.BaseDirectory + "file1.xml");
var resNodes = xmlDoc.SelectNodes("//myself");
XmlNode res = null;
var val = textBox1.Text;
var item = from XmlNode x in resNodes
select x;
foreach (var nodP in item) {
foreach (XmlNode nod in nodP.ChildNodes) {
if (nod.InnerText == val) {
res = nodP;
}
}
}
if (res == null)
// not found!
;
else
// show the result
;

Call me old fashioned but you could use an XPath, for example:
string xml =
#"<main>
<myself>
<pid>1</pid>
<name>abc</name>
</myself>
<myself>
<pid>2</pid>
<name>efg</name>
</myself>
</main>";
using System.Xml;
....
XmlDocument xmlDocument = new XmlDocument();
xmlDocument.LoadXml(xml);
// Replace "2" in the string below with the desired pid
XmlNode xmlNode =
xmlDocument.DocumentElement.SelectSingleNode("myself/name[../pid=2]");
// xmlNode contains the <name>efg</name> XmlElement. For example:
string name = xmlNode.Value;
If it can match multiple nodes, for example there could be multiple <myself> elements with a child element <pid> set to 2, use the following instead:
foreach(XmlNode xmlNode in
xmlDocument.DocumentElement.SelectNodes("myself/name[../pid=2]"))
{
// xmlNode contains the matching <name> element
}
In both cases, the value can be extracted from the XmlNode using the Value property.

public class simpman
{
private static XElement root = XElement.Load("Simpman.xml");
public static string GetItem(int index)
{
XElement item =
(from element in root.Elements("myself")
where (int)element.Element("pid") == index
select element.Element("name")).SingleOrDefault();
return item != null ? item.Value : "Please check the Index";
}
}
Initialize a static itemIndex to 1 and use it further like itemIndex++ (for Next) and itemIndex-- (for Prev).

private void previousList_Click(object sender, EventArgs e)
{
pid = 14;
XDocument xDoc = XDocument.Load(#"C:\Users\HDAdmin\Documents\Fatty\SliceEngine\SliceEngine\bin\Debug\simpan.xml");
var name = xDoc.Root
.Descendants("myself")
.FirstOrDefault(e => e.Element("pid")
.Value
.Equals(pid.ToString(CultureInfo.InvariantCulture)))
.Element("name")
.Value;
textETA.Text = name;
}

XmlDocument doc = new XmlDocument();
FileStream fs = new FileStream(rootXMLPath, FileMode.Open, FileAccess.Read);
doc.Load(fs);
XmlNode node = doc.DocumentElement;
nodeName = "/main/myself";
var child1 = node.SelectSingleNode(nodeName).ChildNodes[0].FirstChild.InnerXml;
var child2 = node.SelectSingleNode(nodeName).ChildNodes[0].LastChild.InnerXml;
var child3 = node.SelectSingleNode(nodeName).ChildNodes[1].FirstChild.InnerXml;
var child4 = node.SelectSingleNode(nodeName).ChildNodes[1].LastChild.InnerXml;