Develop Reference

getting "null" value for xml

in this xml
<Roots>
<Root Name="cab">element_list</Root>
</Roots>
I want to get the value of attribute Name which is cab and element_list
I have this code
XmlDocument doc = new XmlDocument();
doc.LoadXml("<Root Name=\"cab\">element_list</Root>");
XmlElement root = doc.DocumentElement;
var values = doc.Descendants("Roots").Select(x => new { Name = (string)x.Attribute("Name"), List = (string)x }).ToList();
What I get when I run the debugger is
values> Name = "null", List = "element_list"
I am not understanding why I am getting a null value when I should be getting cab for the attribute Name

XDocument is much easier to work with compared to XmlDocument. Perhaps consider switching to it?
public static void ParseXml()
{
string str = "<Roots><Root Name=\"cab\">element_list</Root></Roots>";
using TextReader textReader = new StringReader(str);
XDocument doc = XDocument.Load(textReader);
var val = doc.Element("Roots").Element("Root").Attribute("Name").Value;
}

Get element from xml file in c#

I have an xml file which contains an element .
i am storing the content of that xml file as string in csv in one of my projects.i am reading the content of that xml from csv and i want the data of the tag which exists in the content of xml file
I tried like this.
XmlDocument doc = new XmlDocument();
doc.LoadXml(Convert.ToString(dataRow["XML"]));
var temp = doc.GetElementsByTagName("Mail");
but I am not getting the value of Mail into temp.what should i do?

GetElementsByTagName returns XmlNodeList. MSDN Reference
// Display all the book titles.
XmlNodeList elemList = doc.GetElementsByTagName("title");
for (int i=0; i < elemList.Count; i++)
{
Console.WriteLine(elemList[i].InnerXml);
}
Linq solution:
var xDoc = XDocument.Load(dataRow["XML"].ToString());
var mailList = xDoc.Descendants("Mail")
.Select(x => new
{
MailID = x.Element("MailID").Value
})
.ToList();
UPDATE:
XmlDocument doc = new XmlDocument();
doc.LoadXml(Convert.ToString(dataRow["XML"]));
var temp = doc.GetElementsByTagName("Mail");
// loop through all retrieved "Mail" elements
foreach(XmlElement xElem in temp)
{
string sMailText = xElem.InnerText;
}

How to insert xml data into existing xml in c#?

i added xml file in my windows application, i want to add values to that from textbox..
i used the following code,
string path = "codedata.xml";
XmlDocument doc = new XmlDocument();
if (!System.IO.File.Exists(path))
{
//Create neccessary nodes
XmlDeclaration declaration = doc.CreateXmlDeclaration("1.0", "UTF-8", "yes");
XmlComment comment = doc.CreateComment("This is an XML Generated File");
doc.AppendChild(declaration);
doc.AppendChild(comment);
}
else //If there is already a file
{
// //Load the XML File
doc.Load(path);
}
//Get the root element
XmlElement root = doc.DocumentElement;
XmlElement Subroot = doc.CreateElement("data");
XmlElement Companycode = doc.CreateElement("Companycode");
XmlElement Productcode = doc.CreateElement("Productcode");
XmlElement Productname = doc.CreateElement("Productname");
XmlElement Brandcode = doc.CreateElement("Brandcode");
XmlElement Brandname = doc.CreateElement("Brandname");
Companycode.InnerText = txt_companycode.Text;
Productcode.InnerText = txt_productcode.Text;
Productname.InnerText = txt_productname.Text;
Brandcode.InnerText = txt_brandcode.Text;
Brandname.InnerText = txt_brandname.Text;
Subroot.AppendChild(Companycode);
Subroot.AppendChild(Productcode);
Subroot.AppendChild(Productname);
Subroot.AppendChild(Brandcode);
Subroot.AppendChild(Brandname);
root.AppendChild(Subroot);
doc.AppendChild(root);
//Save the document
doc.Save(path);
//Show confirmation message
MessageBox.Show("Details added Successfully");
it showing error near root.AppendChild(Subroot); can any one help me, wer i made mistake.

You can use Linq to XML, here is an example :
var xDoc = XElement.Load("FilePath");
if (xDoc == null)
return;
var myNewElement = new XElement("ElementName"
new XAttribute("AttributeName", value1),
new XAttribute("AttributeName", value2)
//And so on ...
);
xDoc.Add(myNewElement);
xDoc.Save("FilePath");

The root is null. Try to add Root element when you create XML file.
if (!System.IO.File.Exists(path))
{
//Create neccessary nodes
XmlDeclaration declaration = doc.CreateXmlDeclaration("1.0", "UTF-8", "yes");
XmlComment comment = doc.CreateComment("This is an XML Generated File");
doc.AppendChild(declaration);
doc.AppendChild(comment);
doc.AppendChild(doc.CreateElement("Root"));
}
Or use LINQ-XML
string _file=#"c:\sample.xml";
XDocument doc;
if (!File.Exists(_file))
{
doc = new XDocument();
doc.Add(new XElement("Root"));
}
else
{
doc = XDocument.Load(_file);
}
doc.Root.Add(
new XElement("data",
new XElement("CompanyCode","C101"),
new XElement("ProductCode","P101")
)
);
doc.Save(_file);

In null XML DocumentElement is null. Try add Subroot to Document:
XmlElement root = doc.DocumentElement;
root.AppendChild(Subroot);
doc.AppendChild(root);
// new code
doc.AppendChild(Subroot);

Deleting XML using a selected Xpath and a for loop

I currently have the following code:
XPathNodeIterator theNodes = theNav.Select(theXPath.ToString());
while (theNodes.MoveNext())
{
//some attempts i though were close
//theNodes.RemoveChild(theNodes.Current.OuterXml);
//theNodes.Current.DeleteSelf();
}
I have set xpath to what I want to return in xml and I want to delete everything that is looped. I have tried a few ways of deleting the information but it does't like my syntax. I found an example on Microsoft support: http://support.microsoft.com/kb/317666 but I would like to use this while instead of a for each.
Any comments or questions are appreciated.

Why not to use XDocument?
var xmlText = "<Elements><Element1 /><Element2 /></Elements>";
var document = XDocument.Parse(xmlText);
var element = document.XPathSelectElement("Elements/Element1");
element.Remove();
var result = document.ToString();
result will be <Elements><Element2 /></Elements>.
Or:
var document = XDocument.Load(fileName);
var element = document.XPathSelectElement("Elements/Element1");
element.Remove();
document.Savel(fileName);
[Edit] For .NET 2, you can use XmlDocument:
XmlDocument document = new XmlDocument();
document.Load(fileName);
XmlNode node = document.SelectSingleNode("Elements/Element1");
node.ParentNode.RemoveChild(node);
document.Save(fileName);
[EDIT]
If you need to remove all child elements and attributes:
XmlNode node = document.SelectSingleNode("Elements");
node.RemoveAll();
If you need to keep attributes, but delete elements:
XmlNode node = document.SelectSingleNode("Elements");
foreach (XmlNode childNode in node.ChildNodes)
node.RemoveChild(childNode);

string nodeXPath = "your x path";
XmlDocument document = new XmlDocument();
document.Load(/*your file path*/);
XmlNode node = document.SelectSingleNode(nodeXPath);
node.RemoveAll();
XmlNode parentnode = node.ParentNode;
parentnode.RemoveChild(node);
document.Save("File Path");

You can use XmlDocument:
string nodeXPath = "your x path";
XmlDocument document = new XmlDocument();
document.Load(/*your file path*/);//or document.LoadXml(...
XmlNode node = document.SelectSingleNode(nodeXPath);
if (node.HasChildNodes)
{
//note that you can use node.RemoveAll(); it will remove all child nodes, but it will also remove all node' attributes.
for (int childNodeIndex = 0; childNodeIndex < node.ChildNodes.Count; childNodeIndex++)
{
node.RemoveChild(node.ChildNodes[childNodeIndex]);
}
}
document.Save("your file path"));

writing to xml attributes

Hey all i have code to write to an xml doc from asp
string filePath = Server.MapPath("../XML/MyXmlDoc.xml");
XmlDocument xmlDoc = new XmlDocument();
try
{
xmlDoc.Load(filePath);
}
catch (System.IO.FileNotFoundException)
{
//if file is not found, create a new xml file
XmlTextWriter xmlWriter = new XmlTextWriter(filePath, System.Text.Encoding.UTF8);
xmlWriter.Formatting = Formatting.Indented;
xmlWriter.WriteProcessingInstruction("xml", "version='1.0' encoding='UTF-8'");
string startElement = "markings";
xmlWriter.WriteStartElement(startElement);
xmlWriter.Close();
xmlDoc.Load(filePath);
}
XmlNode root = xmlDoc.DocumentElement;
XmlElement mainNode = xmlDoc.CreateElement("mark");
XmlElement childNode1 = xmlDoc.CreateElement("studentFirstName");
XmlElement childNode2 = xmlDoc.CreateElement("studentLastName");
XmlElement childNode3 = xmlDoc.CreateElement("className");
XmlElement childNode4 = xmlDoc.CreateElement("marks");
XmlText childTextNode1 = xmlDoc.CreateTextNode("");
XmlText childTextNode2 = xmlDoc.CreateTextNode("");
XmlText childTextNode3 = xmlDoc.CreateTextNode("");
XmlText childTextNode4 = xmlDoc.CreateTextNode("");
root.AppendChild(mainNode);
//this portion can be added to a foreach loop if you need to add multiple records
childTextNode1.Value = "John";
childTextNode2.Value = "Doe";
childTextNode3.Value = "Biology";
childTextNode4.Value = "99%";
mainNode.AppendChild(childNode1);
childNode1.AppendChild(childTextNode1);
mainNode.AppendChild(childNode2);
childNode2.AppendChild(childTextNode2);
mainNode.AppendChild(childNode3);
childNode3.AppendChild(childTextNode3);
mainNode.AppendChild(childNode4);
childNode4.AppendChild(childTextNode4);
//end of loop section
xmlDoc.Save(filePath);
which works fine but i want to store the xml in the following structure
graph
set name="John Doe" value="99";
/graph
instead of
name John Doe /name
value 99 /value
is there a way to store the xml like this? thanks all

You can add an attribute to your XmlElement by using the following syntax (C#) :
XmlAttribute value = xmlDoc.CreateAttribute("value");
childNode1.attributes.appendChild(value);
Hope this helps !

This code will do what you're looking for:
XmlElement graph = xmlDoc.CreateElement("graph");
XmlAttribute name = xmlDoc.CreateAttribute("name");
name.Value = "John Doe";
XmlAttribute value = xmlDoc.CreateAttribute("value");
value.Value = "99";
graph.SetAttributeNode(name);
graph.SetAttributeNode(value);
mainNode.AppendChild(graph);