Develop Reference

XML node is missing when empty

I have an XMLDocument as result of query.
I would like to extract the <Property> value and the appropriate <Notes> for each entry.
<?xml version="1.0"?>
<EADATA version="1.0" exporter="Enterprise Architect">
<Dataset_0>
<Data>
<Row>
<PropertyID>439</PropertyID>
<Object_ID>683</Object_ID>
<Property>tagged value</Property>
<ea_guid>{5BF3E019-277B-45c2-B2DE-1887A90C6944}</ea_guid>
</Row>
<Row>
<PropertyID>444</PropertyID>
<Object_ID>683</Object_ID>
<Property>Another Tagged value</Property>
<Notes>Another tagged value notes.</Notes>
<ea_guid>{42BE8BAA-06B8-4822-B79A-59F653C44453}</ea_guid>
</Row>
</Data>
</Dataset_0>
</EADATA>
However, If the <Notes> is empty there is no <Notes> tag at all.
What XPath should I write in such cases?

Which value do you want if there is no Notes element, a null, an empty string?
I would select the Row elements with SelectNodes and then check whether a Notes child exists and assign null (as done below) or the empty string if not:
foreach (XmlElement row in doc.SelectNodes("//Row"))
{
string prop = row.SelectSingleNode("Property").InnerText;
string notes = row.SelectSingleNode("Notes") != null ? row.SelectSingleNode("Notes").InnerText : null;
}

Try this :
XPathDocument docNav = new XPathDocument(new StringReader(xml));
XPathNavigator navigator = docNav.CreateNavigator();
XPathNodeIterator NodeIter = navigator.Select("/EADATA/Dataset_0/Data/Row");
foreach (XPathNavigator selectedNode in NodeIter)
{
var a= "<root>" + selectedNode.InnerXml + "</root>";
var x= XDocument.Parse(a);
Console.WriteLine (x.Root.Element("Property").Value);
if (x.Root.Element("Notes")!=null)
Console.WriteLine (x.Root.Element("Notes").Value);
}
result :
tagged value
Another Tagged value
Another tagged value notes.

Unable to remove root node from an xml document using linq to xml c#

Actullay, I need to get all elements except root node from first xml document and so that I could insert them as child nodes to an element(that has same name as a previous doc's root name) in a new document.
So I have tried various ways to achieve it, one of them is removing the root node of first and then trying to add elements to a new one's as given below:
I have tried the following but could not achieve it.
XDocument testDoc = XDocument.Parse(Mydocument);
testDoc.Descendants().Where(e => e.Name.LocalName == "rootName").Select(m=>m).Single().Remove();
var resultDoc = testDoc;
The above code is giving me an empty "{}" result.
my xml document looks something like the below one's:
<rootName xsi:schemaLocation="" xmlns:xsi="" xmlns="">
<main>
<child>
</child>
<anotherchild>
</anotherchild>
</main>
</rootName>
And another way is getting all the elements of first document as the following:
var resultDoc = testDoc.Descendants(ns + "rootName").Elements();
the above statement is giving me the list of elements in the "testDoc" which
I need to do something like below, I am clueless:
<AnotherDocument xsi:schemaLocation="" xmlns:xsi="" xmlns="">
<firstNode>
<rootName>
<main>
<child>
</child>
<anotherchild>
</anotherchild>
</main>
</rootName>
</firstNode>
Please let me know how to insert those elements in a new document as above if I am correct else let me know the way to resolve this issue.
Thanks in advance.

You can replace content of rootName element in another document with elements from first document root:
var xDoc = XDocument.Parse(Mydocument);
var anotherXDoc = XDocument.Load("anotherdata.xml");
XNamespace ns = "http://..."; // your xml namespance
var rootName = anotherXDoc.Descendants(ns + "rootName").First();
rootName.ReplaceNodes(xDoc.Root.Elements());

By this page_nodes gets all nodes now you can used all node by for each loop
var page_nodes = from p in xdoc.Descendants.Where(e => e.Name.LocalName == "rootName").Select(m=>m).Single().Remove() select p;
foreach (var page_node in page_nodes)
{
//Do stuff
}

Wouldn't removing a root node, remove all its child nodes as well? The result you are getting is to be expected I think. You should probably get all the children of the root and copy them to your new document.

Selecting values from an xml document object with XPATH in code behind (c#)

I am trying to select specific values from a xml document using XPath. The xml is stored into a string varibale "tmp". This xml is the result of a query performed on a external API.
sample XML contents:
<?xml version="1.0" encoding="ISO-8859-1"?>
<Results>
<Checks>
<Check id="wbc">
<Linespeed>6000 </Linespeed>
<Provider>BT WBC </Provider>
</Check>
<Check id="adsl">
<Linespeed>2048 </Linespeed>
<Provider>BT ADSL </Provider>
</Check>
</Checks>
</Results>
Using XPATH in code behind I want to be able to select the and only for id=adsl, then store the value in a string variable for later use. I want to achieve this withouth the use of a separate xslt stylesheet.
Here is the code I have written for this but I am getting an error:
//Creating an XPATH epression
String strExpression1;
strExpression1 = "Results/Checks/Check[#id = 'adsl']/Linespeed";
//Loading the xml document
XmlDocument doc;
doc = new XmlDocument();
doc.LoadXml(tmp);
//Create an XmlNamespaceManager to resolve the default namespace.
XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);
nsmgr.AddNamespace("bk", "urn:schemas-microsoft-com:xslt");
//Selecting Linespeed from Check id='adsl'
XmlNode Check;
XmlElement root = doc.DocumentElement;
Check = root.SelectSingleNode(strExpression1, nsmgr);
//Assigning the the results of the XPATH expression to the variable Linespeedval
string Linespeedval = Check.ToString();
//Adding a control to display the xpath results of the "tmp" xml objectt
AvailabilityCheckerResults2.Controls.Add(new LiteralControl(Linespeedval));
Any assistance will be greately appreciated! Thanks in advance!

strExpression1 = "/Results/Checks/Check[#id = 'adsl']/Linespeed";
//or strExpression1 = "//Checks/Check[#id = 'adsl']/Linespeed";
//doc has no namespace
Check = root.SelectSingleNode(strExpression1);
....
string Linespeedval = Check.InnerText;

Take a look at this article. It has step by step instruction to parse xml using xpath.
How to query XML with an XPath expression by using Visual C#

linq update issue

I have a xml document that has a record set like this.
<document>
<row>
<Pub_Code>OHB-A0011</Pub_Code>
<Sec>16</Sec>
<Pags>20</Pags>
<Copies>1,000</Copies>
<Binding>Saddle Stitch</Binding>
<Tab>No tabs</Tab>
<Qty>0</Qty>
<Cover>Self Cover</Cover>
<Tpgs>0</Tpgs>
</row>
</document>
I have a linq query wrtten this way:
string xml_path = #"D:\Server-Apps\BooksData.xml";
XElement root = XElement.Load(xml_path);
var selected = from myBooks in root.Elements("row") where myBooks.Element("Pub_Code").Value == "OHB-A0011" select myBooks;
foreach (var d in selected)
{
Console.WriteLine("Pub_Code: {0}", d.Element("Pub_Code").Value);
Console.WriteLine("Cover: {0}", d.Element("Cover").Value);
d.SetElementValue("Tpgs", "test");
}
I can read the value find but when I uses d.SetElementValue("Tpgs", "test"); nothing gets update.
the tag is already in the xml file .

If you want to save the updated XML back to the file, you need to do:
root.Save(xml_path);
I added the line t the end of your program and it seems to work correctly.

Direct access and edit to an xml node, using properties

El Padrino showed a solution:
How to change XML Attribute
where an xml element can be loaded directly (no for each..), edited and saved!
My xml is:
<?xml version="1.0" encoding="ISO-8859-8"?>
<g>
<page no="1" href="page1.xml" title="נושא 1">
<row>
<pic pos="1" src="D:\RuthSiteFiles\webSiteGalleryClone\ruthCompPics\C_WebBigPictures\100CANON\IMG_0418.jpg" width="150" height="120">1</pic>
</row>
</page>
</g>
and I need to select a node by two attributes(1. "no" in the page tag and "pos" in the pic tag)
I've found :
How to access a xml node with attributes and namespace using selectsinglenode()
where direct access is possible but beside the fact that I dont understand the solution, I think it uses the xpath object which can't be modified and save changes.
What's the best way to
access directly an xml node (I'm responsible that the node will be unique)
edit that node
save changes to the xml
Thanks
Asaf

You can use the same pattern as the first answer you linked to, but you will need to include the conditions on the attributes in the XPath. Your basic XPath would be g/page/row/pic. Since you want the no attribute of page to be 1, you add [#no='1'] as a predicate on page. So, the full XPath query is something like g/page[#no='1']/row/pic[#pos='1']. SelectSingleNode will return a mutable XmlNode object, so you can modify that object and save the original document to save changes.
Putting the XPath together with El Padrino's answer:
//Here is the variable with which you assign a new value to the attribute
string newValue = string.Empty;
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(xmlFile);
XmlNode node = xmlDoc.SelectSingleNode("g/page[#no='1']/row/pic[#pos='1']");
node.Attributes["src"].Value = newValue;
xmlDoc.Save(xmlFile);
//xmlFile is the path of your file to be modified

Use the new, well-designed XDocument/XElement instead of the old XmlDocument API.
In your example,
XDocument doc = XDocument.Load(filename);
var pages = doc.Root.Elements("page").Where(page => (int?) page.Attribute("no") == 1);
var rows = pages.SelectMany(page => page.Elements("row"));
var pics = rows.SelectMany(row => row.Elements("pic").Where(pic => (int?) pic.Attribute("pos") == 1));
foreach (var pic in pics)
{
// outputs <pic pos="1" src="D:\RuthSiteFiles\webSiteGalleryClone\ruthCompPics\C_WebBigPictures\100CANON\IMG_0418.jpg" width="150" height="120">1</pic>
Console.WriteLine(pic);
// outputs 1
Console.WriteLine(pic.Value);
// Changes the value
pic.Value = 2;
}
doc.Save(filename);