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how to extract particular attribute from xml file using c#?

static void Main(string[] args)
{
WebClient _httpReq = new WebClient(); // to talk to the web only for get method
string response = _httpReq.DownloadString("https://open-ic.epic.com/FHIR/api/FHIR/DSTU2/Patient?family=Argonaut&given=Jason");
Console.WriteLine(response);\\prints the xml string fetched from FHIR provider EPIC
XmlDocument xml = new XmlDocument();
xml.LoadXml(response); // suppose that myXmlString contains "<Names>...</Names>"
XmlNodeList xnList = xml.SelectNodes("/entry/resource/patient/name");
// here code is trying to extract the name attribute
foreach (XmlNode xn in xnList)
{
string firstName = xn["family value"].InnerText;
string lastName = xn["given value"].InnerText;
Console.WriteLine("Name: {0} {1}", firstName, lastName);
//print the first name and last name of the patient
}
Console.ReadLine();
}

i do it like this:
XmlDocument MyDocument = new XmlDocument();
MyDocument.Load("...");
XmlNode MyNode = MyDocument.SelectSingleNode("/Node_Name");
foreach (XmlAttribute MyAttribute in MyNode.Attributes)
{
if (MyAttribute.Name == "Attribute_Name")
{
object Value = MyAttribute.Value;
break;
}
}

Review XPath. Once you start understanding it, you will find it efficient and easier to code than iterating through lists. It also lets you directly get the nodes/attributes you want.
Then the code would be something similar to
string attrVal = doc.SelectSingleNode("/entry/resource/patient/#name").Value;
Or you can Load XML in XMlDocument and You can fetch element and out of that element you can read specific atairbute,
XmlDocument doc = new XmlDocument();
doc.LoadXml("<reply success=\"true\">More nodes go here</reply>");
XmlElement root = doc.DocumentElement;
string s = root.Attributes["success"].Value;

Can not read XML document containing ampersand symbol

I am writing a program that reads a XML file with Visual C#. I have a problem reading the Xml file, because it contains invalid XML symbols, for example '&'.
I have to read the XML but I can not modify the document. How can I modify the Xml file using C#? My code so far:
private void button1_Click(object sender, EventArgs e)
{
XmlDocument doc;
doc = new XmlDocument();
doc.Load("nuevo.xml");
XmlNodeList Xpersonas = doc.GetElementsByTagName("personas");
XmlNodeList Xlista = ((XmlElement)Xpersonas[0]).GetElementsByTagName("edad");
foreach (XmlElement nodo in Xlista)
{
string edad = nodo.GetAttribute("edad");
string nombre = nodo.InnerText;
textBox1.Text = nodo.InnerXml;
}

As #EBrown suggested, one possibility would be read the file content in a string variable and replace the & symbol with the correct representation for propert XML & and then parse the XML structure. A possible solution could look like this:
var xmlContent = File.ReadAllText(#"nuevo.xml");
XmlDocument doc;
doc = new XmlDocument();
doc.LoadXml(xmlContent.Replace("&", "&"));
XmlNodeList Xpersonas = doc.GetElementsByTagName("personas");
XmlNodeList Xlista = ((XmlElement)Xpersonas[0]).GetElementsByTagName("edad");
foreach (XmlElement nodo in Xlista)
{
string edad = nodo.GetAttribute("edad");
string nombre = nodo.InnerText;
Console.WriteLine(nodo.InnerXml.Replace("&", "&"));
}
The output is:
34 & 34
If it is ok to use LINQ2XML, then the solution is even shorter, and there is no need to write the reverse(second) replace, because LINQ2XML make this for you automatically:
var xmlContent = File.ReadAllText(#"nuevo.xml");
var xmlDocument = XDocument.Parse(xmlContent.Replace("&", "&"));
var edad = xmlDocument.Root.Element("edad").Value;
Console.WriteLine(edad);
The output is the same as above.

Inserting data at specific position in XML

I want to read an XML file and match tag </contrib-group> and write a string after this tag
string Final = File.ReadAllText(Npath);
string Oxml = path + "\\" + Oword + ".abs.xml";
if (File.Exists(Oxml))
{
StreamReader xml = new StreamReader(Oxml,Encoding.UTF8);
string xmltag = xml.ReadToEnd();
//File.OpenWrite(Oxml);
xml.Close();
StreamWriter write = new StreamWriter(Oxml, true, Encoding.UTF8);
Match tag = Regex.Match(xmltag, #"</contrib-group>");
if (tag.Success == true)
{
write.WriteLine(Environment.NewLine);
write.Write(Final);
}
}
So I need to write the string Final to the XML file called Oxml after the matched XML tag </contrib-group>

If you are willing to save the new content as a valid XML file which you can work with, you should use the XML classes for that approach, this should look like this (untested):
XmlDocument doc = new XmlDocument();
doc.Load("YourFile.xml");
XmlElement root = doc.DocumentElement;
XmlNodeList elemList = root.GetElementsByTagName("contrib-group");
for (int i=0; i < elemList.Count; i++)
{
XmlNode xnode = elemList[i];
XmlNode xnodeParent = xnode.ParentNode;
XMLNode newNode = doc.CreateNode(XmlNodeType.Element, "NodeName", "");
newNode.InnerText = "ContentInsideTheNode";
xnodeParent.InsertAfter(newNode, xnode);
}
doc.Save("YourFile.xml");
If you only need to replace the string for other purposes than saving it where having a valid XML is not an issue you can just handle it as a string and use the String.Replace (String, String) Method
string searchedTag = #"</contrib-group>";
string tagAndNewContent = #"</contrib-group>" + newContent;
string fileContentString = File.ReadAllText("YourFile.xml");
string ouput = fileContentString.Replace(searchedTag, tagAndNewContent);

Combine two XMLDocuments rss

I've got two rss feeds I would like to merge together to make one. I've actually managed to merge the two feeds together and place the items in correct place - however the data in each attribute, i.e. title contains title+link+description+author+pubDate - and that repeats for link, description, author and pubdate. Can someone help me dubug it please?
Object rssData = new object();
Cms.UI.CommonUI.ApplicationAPI AppAPI = new Cms.UI.CommonUI.ApplicationAPI();
rssData = AppAPI.ecmRssSummary(50, true, "DateCreated", 0, "");
Response.ContentType = "text/xml";
Response.ContentEncoding = System.Text.Encoding.UTF8;
XmlDocument xmlDocument = new XmlDocument();
xmlDocument.LoadXml(rssData.ToString());
//************************************************************
// Obtain 5 data items from second list
Object rssData1 = new object();
Cms.UI.CommonUI.ApplicationAPI AppAPI1 = new Cms.UI.CommonUI.ApplicationAPI();
rssData1 = AppAPI1.ecmRssSummary(60, true, "DateCreated", 5, "");
XmlDocument xmlDocument1 = new XmlDocument();
xmlDocument1.LoadXml(rssData1.ToString());
XmlNodeList nl = xmlDocument1.SelectNodes("/rss/channel");
XmlNode root = nl[0]; //do I need this line?
foreach (XmlNode xnode1 in root.ChildNodes)
{
string title = xnode1.InnerText;
string link = xnode1.InnerText;
string desc = xnode1.InnerText;
string auth = xnode1.InnerText;
string pdate = xnode1.InnerText;
//Merge new nodes
node = xmlDocument.CreateNode(XmlNodeType.Element, "item", null);
//node.InnerText = "this is new node";
//create title node
XmlNode nodeTitle = xmlDocument.CreateElement("title");
nodeTitle.InnerText = title;
//create Link node
XmlNode nodeLink = xmlDocument.CreateElement("link");
nodeLink.InnerText = link;
XmlNode nodeDesc = xmlDocument.CreateElement("description");
nodeDesc.InnerText = desc;
XmlNode nodeAuthor = xmlDocument.CreateElement("author");
nodeAuthor.InnerText = auth;
XmlNode nodepubDate = xmlDocument.CreateElement("pubDate");
nodepubDate.InnerText = pdate;
//add to parent node
node.AppendChild(nodeTitle);
node.AppendChild(nodeLink);
node.AppendChild(nodeDesc);
node.AppendChild(nodeAuthor);
node.AppendChild(nodepubDate);
//add to elements collection
//xmlDocument.DocumentElement.AppendChild(node);
xmlDocument.DocumentElement.SelectNodes("/rss/channel")[0].AppendChild(node);
}
//********************************************
xmlDocument.Save(Response.Output);

As you rightly suspected, the problem is here:
string title = xnode1.InnerText;
string link = xnode1.InnerText;
string desc = xnode1.InnerText;
string auth = xnode1.InnerText;
string pdate = xnode1.InnerText;
No wonder that
the data in each attribute, i.e. title contains
title+link+description+author+pubDate - and that repeats for link,
description, author and pubdate.
You need to read the values of specific subelements of each node. Probably something like:
string title = xnode1["title"].InnerText;
etc.
See http://www.csharp-examples.net/xml-nodes-by-name/ for reference.

Konrad's answer is clear, but it might not work if there's nested tags within the title tag.
Say, <title> TEXT <tag1> OTHER_TEXT </tag1></title>
On my computer, it will return you a concatenation of TEXT and OTHER_TEXT.
This should work:
string title = xnode1["title"].FirstChild.Value;
FirstChild will get you the TEXT no matter whether there is other tags with the title or not.

C# Pull XML data from google's weather API

I've been using this code to try and get data from the google weather API, but I never get even close to pulling out what i want.
My goal is to look at:
<forecast_information>
**<city data="london uk"/>**
<postal_code data="london uk"/>
<latitude_e6 data=""/>
<longitude_e6 data=""/>
<forecast_date data="2011-10-09"/>
<current_date_time data="2011-10-09 12:50:00 +0000"/>
<unit_system data="US"/>
</forecast_information>
<current_conditions>
<condition data="Partly Cloudy"/>
<temp_f data="68"/>
**<temp_c data="20"/>**
**<humidity data="Humidity: 68%"/>**
<icon data="/ig/images/weather/partly_cloudy.gif"/>
**<wind_condition data="Wind: W at 22 mph"/>**
</current_conditions>
And only return the text of the child nodes.
So the result would be:
City: London UK
Temp: 20c
Humidity: 68%
Wind: 22mph
Currently I am trying to use this, but got nowhere...
XmlDocument doc = new XmlDocument();
XmlNodeList _list = null;
doc.Load("http://www.google.com/ig/api?weather=london+uk");
_list = doc.GetElementsByTagName("forecast_information/");
foreach (XmlNode node in _list)
{
history.AppendText(Environment.NewLine + "City : " + node.InnerText);
}
//NOTE, currently code is set to display ALL child nodes
Perhaps someone can shed some light on the matter?

Maybe you should use node.SelectSingleNode("city").Attributes["data"].Value instead of node.InnerText
--EDIT--
This works for me
XmlDocument doc = new XmlDocument();
doc.Load("http://www.google.com/ig/api?weather=london+uk");
var list = doc.GetElementsByTagName("forecast_information");
foreach (XmlNode node in list)
{
Console.WriteLine("City : " + node.SelectSingleNode("city").Attributes["data"].Value);
}
list = doc.GetElementsByTagName("current_conditions");
foreach (XmlNode node in list)
{
foreach (XmlNode childnode in node.ChildNodes)
{
Console.Write(childnode.Attributes["data"].Value + " ");
}
}

Change that to
history.AppendText(Environment.NewLine + "City : " + node.GetAttribute("data"));

using System.Xml.Linq;
using System.Xml.XPath;
XElement doc = XElement.Load("http://www.google.com/ig/api?weather=london+uk");
string theCity = doc.XPathSelectElement(#"weather/forecast_information/city").Attribute("data").Value;
string theTemp = doc.XPathSelectElement(#"weather/current_conditions/temp_c").Attribute("data").Value;
string theHumid = doc.XPathSelectElement(#"weather/current_conditions/humidity").Attribute("data").Value;
string theWind = doc.XPathSelectElement(#"weather/current_conditions/wind_condition").Attribute("data").Value;
string resultString = String.Format("City : {0} Temp : {1}c {2} {3}", theCity, theTemp, theHumid, theWind);