Develop Reference

Insert a string in a particular position into an other string

I am work on some innerxml of an XML document.
I have to concat several parts.
I have this:
<TRANFSERT><GOOD></GOOD></TRANSFERT>
I want to insert another part, <GOOD></GOOD>, before </TRANSFERT>.
I tried this:
int pos = xmldoc.indexOf("</GOOD>");
StringBuilder sb = new StringBuilder(xmlFinal);
sb.Append(xmlModifiee,pos,xmlModifiee.length);
xmlFinal = sb.ToString();
But it doesn't work.
How can I add a small part of XML in other XML?

You shouldn't interact with XML like with ordinary string.
Use provided System.Xml.XmlDocument or System.Xml.Linq.XDocument classes:
Ordinary XmlDocument single node selection and appending new element to it:
XmlDocument xmlDocument = new XmlDocument();
xmlDocument.Load("YourFile.xml");
XmlNode goodNode = xmlDocument.SelectSingleNode("TRANSFERT/GOOD");
XmlNode nodeToInsert = xmlDocument.CreateElement("INSERTEDNODE");
goodNode.AppendChild(nodeToInsert);
Ordinary XmlDocument iterating by nodes to find necessary (be aware for many-childed nodes) and add new child node to it:
XmlDocument xmlDocument = new XmlDocument();
xmlDocument.Load("YourFile.xml");
foreach (XmlNode rootNode in xmlDocument.ChildNodes)
{
if (rootNode.Name == "TRANSFERT")
{
foreach (XmlNode childNode in rootNode.ChildNodes)
{
if (childNode.Name == "GOOD")
{
XmlNode nodeToInsert = xmlDocument.CreateElement("INSERTEDNODE");
childNode.AppendChild(nodeToInsert);
}
}
}
}
Linq to XML variant:
XDocument xDoc = XDocument.Load("YourFIle.xml");
XElement rootElement = xDoc.Element("TRANSFERT");
XElement goodElement = rootElement.Element("GOOD");
goodElement.Add(new XElement("INSERTEDNODE"));
Simplified Linq to XML variant:
XDocument.Load("YourFIle.xml").Element("TRANSFERT").Element("GOOD").Add(new XElement("INSERTEDNODE"));
EDITED: answering the question, example was rewrited from changing InnerText values to Append/Add new child element to GOOD node.

StringBuilder.Append can only be used to add something to the end of the string. To add something inside the string, use StringBuilder.Insert like this:
sb.Insert(pos, xmlModifiee);

Selecting value from first xml child node

I have an XML file that contains multiple URLs for different image file sizes, and I'm trying to get a single url to load into a picture box. My issue is that the child nodes are named similarly, and the parent nodes are named similarly as well. For example, I want to pull the first medium image (ending in SL160_.jpg). See below for XML code
<Items>
<SmallImage>
<URL>http://ecx.images-amazon.com/images/I/51TAL%2Bn7AqL._SL75_.jpg</URL>
</SmallImage>
<MediumImage>
<URL>http://ecx.images-amazon.com/images/I/51TAL%2Bn7AqL._SL160_.jpg</URL>
</MediumImage>
<LargeImage>
<URL>http://ecx.images-amazon.com/images/I/51TAL%2Bn7AqL.jpg</URL>
</LargeImage>
<MediumImage>
<URL>http://ecx.images-amazon.com/images/I/51TAL%2Bn7AqL._SL162_.jpg</URL>
</MediumImage>
<LargeImage>
<URL>http://ecx.images-amazon.com/images/I/51TAL%2Bn7AqL.jpg</URL>
</LargeImage>
</Items>
I've tried using GetElementsByTag, as well as trying to call something like doc.SelectSingleNode("LargeImage").SelectSingleNode("URL").InnerText, and GetElementByID. All of these have given me an Object set to null reference exception.
What can I do to specify that I want the url from the first found MediumImage node?

Use LinqToXML，It is rather simple
string xml = #"<Items>
<SmallImage>
<URL>http://ecx.images-amazon.com/images/I/51TAL%2Bn7AqL._SL75_.jpg</URL>
</SmallImage>
<MediumImage>
<URL>http://ecx.images-amazon.com/images/I/51TAL%2Bn7AqL.01_SL160_.jpg</URL>
</MediumImage>
<LargeImage>
<URL>http://ecx.images-amazon.com/images/I/51TAL%2Bn7AqL.jpg</URL>
</LargeImage>
<MediumImage>
<URL>http://ecx.images-amazon.com/images/I/51TAL%2Bn7AqL.02_SL162_.jpg</URL>
</MediumImage>
<LargeImage>
<URL>http://ecx.images-amazon.com/images/I/51TAL%2Bn7AqL.jpg</URL>
</LargeImage>
</Items>";
XElement root = XElement.Parse(xml);
var ele = root.Elements("MediumImage").Where(e => e.Element("URL").Value.EndsWith("SL160_.jpg")).FirstOrDefault();
Console.WriteLine(ele);

In addition to Sky Fang's answer, I think the OP wants this:
var firstMedImg = root.Elements("MediumImage").First();
var imgUrl = firstMedImg.Element("URL").Value;

XmlDocument doc = new XmlDocument();
// PATH TO YOUR DOCUMENT
doc.Load("daco.xml");
// Select LIST ALL ELEMENTS SmallImage,MediumImage,LargeImage
XmlNodeList listOfAllImageElements = doc.SelectNodes("/Items/*");
foreach (XmlNode imageElement in listOfAllImageElements)
{
// Select URL ELEMENT
XmlNode urlElement= node.SelectSingleNode("URL");
System.Console.WriteLine(urlElement.InnerText);
}
Console.ReadLine();
If you want to select multiple url's
XmlDocument doc = new XmlDocument();
// PATH TO YOUR DOCUMENT
doc.Load("daco.xml");
// Select LIST ALL ELEMENTS SmallImage,MediumImage,LargeImage
XmlNodeList listOfAllImageElements = doc.SelectNodes("/Items/*");
foreach (XmlNode imageElement in listOfAllImageElements)
{
// Select URL's ELEMENTs
XmlNodeList listOfAllUrlElements = imageElement.SelectNodes("URL");
foreach (XmlNode urlElement in listOfAllUrlElements)
{
System.Console.WriteLine(urlElement.InnerText);
}
}
Console.ReadLine();
if you have specific namespace in your xml file
XmlDocument doc = new XmlDocument();
doc.Load("doc.xml");
XmlNamespaceManager man = new XmlNamespaceManager(doc.NameTable);
// reaplace http://schemas.microsoft.com/vs/2009/dgml with your namespace
man.AddNamespace("x", "http://schemas.microsoft.com/vs/2009/dgml");
// next you have to use x: in your path like this
XmlNodeList node = doc.SelectNodes("/x:Items/x:*, man);

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);

XML - how to use namespace prefixes

I have this XML at http://localhost/file.xml:
<?xml version="1.0" encoding="utf-8"?>
<val:Root xmlns:val="http://www.hw-group.com/XMLSchema/ste/values.xsd">
<Agent>
<Version>2.0.3</Version>
<XmlVer>1.01</XmlVer>
<DeviceName>HWg-STE</DeviceName>
<Model>33</Model>
<vendor_id>0</vendor_id>
<MAC>00:0A:DA:01:DA:DA</MAC>
<IP>192.168.1.1</IP>
<MASK>255.255.255.0</MASK>
<sys_name>HWg-STE</sys_name>
<sys_location/>
<sys_contact>
HWg-STE:For more information try http://www.hw-group.com
</sys_contact>
</Agent>
<SenSet>
<Entry>
<ID>215</ID>
<Name>Home</Name>
<Units>C</Units>
<Value>27.7</Value>
<Min>10.0</Min>
<Max>40.0</Max>
<Hyst>0.0</Hyst>
<EmailSMS>1</EmailSMS>
<State>1</State>
</Entry>
</SenSet>
</val:Root>
I am trying to read this from my c# code:
static void Main(string[] args)
{
var xmlDoc = new XmlDocument();
xmlDoc.Load("http://localhost/file.xml");
XmlElement root = xmlDoc.DocumentElement;
// Create an XmlNamespaceManager to resolve the default namespace.
XmlNamespaceManager nsmgr = new XmlNamespaceManager(xmlDoc.NameTable);
nsmgr.AddNamespace("val", "http://www.hw-group.com/XMLSchema/ste/values.xsd");
XmlNodeList nodes = root.SelectNodes("/val:SenSet/val:Entry");
foreach (XmlNode node in nodes)
{
string name = node["Name"].InnerText;
string value = node["Value"].InnerText;
Console.Write("name\t{0}\value\t{1}", name, value);
}
Console.ReadKey();
}
}
Problem is that the node is empty. I understand this is a common newbie problem when reading XML, still not able to solve what I am doing wrong, probably something with the Namespace "val" ?

You need to pass the namespace manager into the SelectNodes()
method.
Edit: corrected code
XmlNodeList nodes = root.SelectNodes("/val:Root/SenSet/Entry", nsmgr);

Just change you Xpath to:
XmlNodeList nodes1 = root.SelectNodes("/val:Root/SenSet/Entry",nsmgr);
Or:
XmlNodeList nodes = root.SelectNodes("SenSet/Entry");

Your xpath query string should be:
XmlNodeList nodes = root.SelectNodes("/val:Root/SenSet/Entry", nsmgr);
or more concisely,
XmlNodeList nodes = root.SelectNodes("//SenSet/Entry", nsmgr);

Read a XML (from a string) and get some fields - Problems reading XML

I have this XML (stored in a C# string called myXML)
<?xml version="1.0" encoding="utf-16"?>
<myDataz xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<listS>
<sog>
<field1>123</field1>
<field2>a</field2>
<field3>b</field3>
</sog>
<sog>
<field1>456</field1>
<field2>c</field2>
<field3>d</field3>
</sog>
</listS>
</myDataz>
and I'd like to browse all <sog> elements. For each of them, I'd like to print the child <field1>.
So this is my code :
XmlDocument xmlDoc = new XmlDocument();
string myXML = "<?xml version=\"1.0\" encoding=\"utf-16\"?><myDataz xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\"><listS><sog><field1>123</field1><field2>a</field2><field3>b</field3></sog><sog><field1>456</field1><field2>c</field2><field3>d</field3></sog></listS></myDataz>"
xmlDoc.Load(myXML);
XmlNodeList parentNode = xmlDoc.GetElementsByTagName("listS");
foreach (XmlNode childrenNode in parentNode)
{
HttpContext.Current.Response.Write(childrenNode.SelectSingleNode("//field1").Value);
}
but seems I can't read a string as XML? I get System.ArgumentException

You should use LoadXml method, not Load:
xmlDoc.LoadXml(myXML);
Load method is trying to load xml from a file and LoadXml from a string. You could also use XPath:
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(xml);
string xpath = "myDataz/listS/sog";
var nodes = xmlDoc.SelectNodes(xpath);
foreach (XmlNode childrenNode in nodes)
{
HttpContext.Current.Response.Write(childrenNode.SelectSingleNode("//field1").Value);
}

Use Linq-XML,
XDocument doc = XDocument.Load(file);
var result = from ele in doc.Descendants("sog")
select new
{
field1 = (string)ele.Element("field1")
};
foreach (var t in result)
{
HttpContext.Current.Response.Write(t.field1);
}
OR : Get the node list of <sog> tag.
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(myXML);
XmlNodeList parentNode = xmlDoc.GetElementsByTagName("sog");
foreach (XmlNode childrenNode in parentNode)
{
HttpContext.Current.Response.Write(childrenNode.SelectSingleNode("field1").InnerText);
}

The other answers are several years old (and do not work for Windows Phone 8.1) so I figured I'd drop in another option. I used this to parse an RSS response for a Windows Phone app:
XDocument xdoc = new XDocument();
xdoc = XDocument.Parse(xml_string);

Or use the XmlSerializer class.
XmlSerializer xs = new XmlSerializer(objectType);
obj = xs.Deserialize(new StringReader(yourXmlString));

I used the System.Xml.Linq.XElement for the purpose. Just check code below for reading the value of first child node of the xml(not the root node).
string textXml = "<xmlroot><firstchild>value of first child</firstchild>........</xmlroot>";
XElement xmlroot = XElement.Parse(textXml);
string firstNodeContent = ((System.Xml.Linq.XElement)(xmlroot.FirstNode)).Value;