Develop Reference

Update XML file with C#

I have a xml file:
<?xml version="1.0" encoding="utf-8"?>
<ApplicationConfiguration xmlns="http://test.org/SDK/Configuration.xsd">
<ApplicationName>
<ApplicationUri>123</ApplicationUri>
<ApplicationUri>456</ApplicationUri>
</ApplicationName>
</ApplicationConfiguration>
What I want is set the value of ApplicationUri from 456 to 789 in C# code.
I wrote this code:
string docaddress = "testfile.xml";
XDocument doc = XDocument.Load(docaddress);
doc.Element("ApplicationConfiguration")
.Elements("ApplicationName").FirstOrDefault()
.SetElementValue("ApplicationUri", "789");
doc.Save(docaddress);
The problems are:
There is no error while running. I think the element ApplicationConfiguration is not correct. But when I delete the line xmlns=... from the xml file, it runs normally
The value 789 is replaced with 123, but not 456 as I want (same element name)
Can you tell me how to fix those problems?

Hello and welcome to Stack Overflow!
The xmlns attribute on the ApplicationConfiguration element makes that the root.
So you get the root first. Then you replace the values of each descendant, selecting locally by name with the element name you want. something like this:
string docaddress = "C:\\temp\\testfile.xml";
XDocument doc = XDocument.Load(docaddress);
var root = doc.Root;
var descendants = root.Descendants();
var these = root.Descendants().Where(p => p.Name.LocalName == "ApplicationUri");
foreach (var elem in these)
{
elem.Value = "789";
}
doc.Save(docaddress);

I added namespace to your code :
string docaddress = "testfile.xml";
XDocument doc = XDocument.Load(docaddress);
XNamespace ns = doc.Root.GetDefaultNamespace();
doc.Element(ns + "ApplicationConfiguration")
.Elements(ns + "ApplicationName").FirstOrDefault()
.SetElementValue(ns + "ApplicationUri", "789");
doc.Save(docaddress);

IMHO, here is an easiest method.
It is taking care of the XML default namespace.
No loops. Set based approach.
c#
void Main()
{
const string fileName = #"e:\temp\hala.xml";
const string searchFor = "456";
const string replaceWith = "789";
XDocument doc = XDocument.Load(fileName);
XNamespace ns = doc.Root.GetDefaultNamespace();
// step #1: find element based on the search value
XElement xmlFragment = doc.Descendants(ns + "ApplicationUri")
.Where(d => d.Value.Equals(searchFor)).FirstOrDefault();
// step #2: if found, set its value
if(xmlFragment != null)
xmlFragment.SetValue(replaceWith);
doc.Save(fileName);
}

Stuck on basic Linq to XML query

I'm trying to extract the information from the namecheap sandbox api and can't figure out why my linq queries aren't working.
Here's a sample response.
XML
<ApiResponse Status="OK" xmlns="http://api.namecheap.com/xml.response">
<Errors />
<Warnings />
<RequestedCommand>namecheap.domains.check</RequestedCommand>
<CommandResponse>
<DomainCheckResult Domain="google.com" Available="false" />
</CommandResponse>
<Server>WEB1-SANDBOX1</Server>
<GMTTimeDifference>--4:00</GMTTimeDifference>
<ExecutionTime>0.875</ExecutionTime>
</ApiResponse>
C#
var doc = XDocument.Load(url);
var response = (
from r in doc.Root.Descendants("ApiResponse")
where 1==1
select new {
Errors = r.Element("Errors").Value,
Warnings = r.Element("Warnings").Value,
RequestedCommand = r.Element("RequestedCommand").Value,
CommandResponse = r.Element("CommandResponse").Value,
Server = r.Element("Server").Value
}
);
I've also tried this query with the same doc just to see if a simple example worked.
var test = doc.Descendants("RequestedCommand").First().Value;
But both return null. So where am I going wrong? I'll eventually need to get at the top level elements and the deeper elements within CommandResponse. Any help with that would also be appreciated.
UPDATE
As Jon's answer mentioned, it was mainly an issue with not using the namespace when referencing the various elements. Also used doc.Elements() rather then doc.Root. Descendants().
Here's an updated working version.
XNamespace ns = "http://api.namecheap.com/xml.response";
var response = (
from r in doc.Elements()
select new
{
Errors = r.Element(ns + "Errors").Value,
Warnings = r.Element(ns + "Warnings").Value,
RequestedCommand = r.Element(ns + "RequestedCommand").Value,
CommandResponse = r.Element(ns + "CommandResponse").Value,
Server = r.Element(ns + "Server").Value
}
);

The problem is that you're not using the namespace when you're looking for elements, descendants etc:
XNamespace ns = "http://api.namecheap.com/xml.response";
var doc = XDocument.Load(url);
var response = doc.Root
.Descendants(ns + "ApiResponse")
.Select(r => new {
Errors = r.Element(ns + "Errors").Value,
...
});
(Note that you never need where 1 == 1 in LINQ... I've changed this from query expression syntax as it wasn't giving you anything.)
The namespace is inherited from the <ApiResponse> element as the default namespace for all the other elements, as it's just xmlns=... rather than specifying an alias.
Also note that if you've shown us the whole XML document, then the above won't find any elements, as you're asking for ApiReponse elements below the root element, whereas it is the root element.

I just got Skeeted ;)
Here's something I did in linqpad to get you one of the elements in the XML
var myxml = #"<ApiResponse Status=""OK"" xmlns=""http://api.namecheap.com/xml.response"">
<Server>WEB1-SANDBOX1</Server>
<Errors />
<Warnings />
<RequestedCommand>namecheap.domains.check</RequestedCommand>
<CommandResponse>
<DomainCheckResult Domain=""google.com"" Available=""false"" />
</CommandResponse>
<GMTTimeDifference>--4:00</GMTTimeDifference>
<ExecutionTime>0.875</ExecutionTime>
</ApiResponse>";
//myxml.Dump();
XNamespace p = "http://api.namecheap.com/xml.response";
var doc1 = XElement.Parse(myxml);
var x = from n in doc1.Elements(p + "Server") select n;
x.First().Value.Dump();

Having issue parsing xml with linq to xml

I am having a problem parsing xml that I receive from Web Service.
The xml looks very simple:
<Result xsi:schemaLocation="urn:yahoo:developer http://developer.yahooapis.com/TimeService/V1/GetTimeResponse.xsd" type="web"><Timestamp>1320677359</Timestamp></Result>
But when I try to parse it with following code I am getting no return results.
XDocument doc = XDocument.Load("http://developer.yahooapis.com/TimeService/V1/getTime?appid=StackSolution");
var datestamp = from ds in doc.Descendants("Result")
select new { currentstamp = ds.Element("Timestamp").Value };
Is there a solution or way to parse it?
Thanks you in advance

You have a couple issues: First, the Result node isn't a descendant. It's the root. Second, you ran into the most common issue when using LINQ to XML - you forgot the namespace. The following should give you what you need:
XElement doc = XElement.Load("http://developer.yahooapis.com/TimeService/V1/getTime?appid=StackSolution");
XNamespace ns = "urn:yahoo:developer";
var datestamp = from ds in doc.DescendantsAndSelf(ns + "Result")
select new { currentstamp = ds.Element(ns + "Timestamp").Value };
Note, this produces an IEnumerable. If you only want the datestamp, consider using FirstOrDefault instead. You may be able to make this simpler by just doing the following:
XElement doc = XElement.Load("http://developer.yahooapis.com/TimeService/V1/getTime?appid=StackSolution");
XNamespace ns = "urn:yahoo:developer";
var datestamp = doc.Element(ns + "Timestamp").Value;

This method avoids the namespace issue using LocalName (unqualified identifier).
var datestamp = doc.Root.Descendants().Where(c => c.Name.LocalName.Equals("Timestamp")).FirstOrDefault().FirstNode.ToString()

XDocument and Linq returns null if the element has xmlns attribute

Newbie with XDocuments and Linq, please suggest a solution to retrieve the data from a particular tag in the xml string:
If I have a XML string from webservice response (I formatted xml for ease):
<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soap:Body>
<GetCashFlowReportResponse xmlns="http://tempuri.org/">
<GetCashFlowReportPdf>Hello!</GetCashFlowReportPdf>
</GetCashFlowReportResponse>
</soap:Body>
</soap:Envelope>
Using the following code, I can get the value only if GetCashFlowReportResponse tag doesn't have "xmlns" attribute. Not sure why? Otherwise, it always return null.
string inputString = "<?xml version=\"1.0\" encoding=\"utf-8\"?><soap:Envelope xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\"><soap:Body><GetCashFlowReportResponse xmlns=\"http://tempuri.org/\"><GetCashFlowReportPdf>Hello!</GetCashFlowReportPdf></GetCashFlowReportResponse></soap:Body></soap:Envelope>"
XDocument xDoc = XDocument.Parse(inputString);
//XNamespace ns = "http://tempuri.org/";
XNamespace ns = XNamespace.Get("http://tempuri.org/");
var data = from c in xDoc.Descendants(ns + "GetCashFlowReportResponse")
select (string)c.Element("GetCashFlowReportPdf");
foreach (string val in data)
{
Console.WriteLine(val);
}
I can't change the web service to remove that attribute. IS there a better way to read the response and get the actual data back to the user (in more readable form)?
Edited:
SOLUTION:
XDocument xDoc = XDocument.Parse(inputString);
XNamespace ns = "http://tempuri.org/";
var data = from c in xDoc.Descendants(ns + "GetCashFlowReportResponse")
select (string)c.Element(ns + "GetCashFlowReportPdf");
foreach (string val in data)
{
Console.WriteLine(val);
}
Note: Even if all the child elements doesn't have the namespace attribute, the code will work if you add the "ns" to the element as I guess childs inherit the namespace from parent (see response from SLaks).

You need to include the namespace:
XNamespace ns = "http://tempuri.org/";
xDoc.Descendants(ns + "GetCashFlowReportResponse")

XName qualifiedName = XName.Get("GetCashFlowReportResponse",
"http://tempuri.org/");
var data = from d in xDoc.Descendants(qualifiedName)

Just ask for the elements using the qualified names:
// create a XML namespace object
XNamespace ns = XNamespace.Get("http://tempuri.org/");
var data = from c in xDoc.Descendants(ns + "GetCashFlowReportResponse")
select (string)c.Element(ns + "GetCashFlowReportPdf");
Note the use of the overloaded + operator that creates a QName with a XML namespace and a local name string.

Use Linq to Xml with Xml namespaces

I have this code :
/*string theXml =
#"<Response xmlns=""http://myvalue.com""><Result xmlns:a=""http://schemas.datacontract.org/2004/07/My.Namespace"" xmlns:i=""http://www.w3.org/2001/XMLSchema-instance""><a:TheBool>true</a:TheBool><a:TheId>1</a:TheId></Result></Response>";*/
string theXml = #"<Response><Result><TheBool>true</TheBool><TheId>1</TheId></Result></Response>";
XDocument xmlElements = XDocument.Parse(theXml);
var elements = from data in xmlElements.Descendants("Result")
select new {
TheBool = (bool)data.Element("TheBool"),
TheId = (int)data.Element("TheId"),
};
foreach (var element in elements)
{
Console.WriteLine(element.TheBool);
Console.WriteLine(element.TheId);
}
When I use the first value for theXml, the result is null, whereas with the second one, I have good values ...
How to use Linq to Xml with xmlns values ?

LINQ to XML methods like Descendants and Element take an XName as an argument. There is a conversion from string to XName that is happening automatically for you. You can fix this by adding an XNamespace before the strings in your Descendants and Element calls. Watch out because you have 2 different namespaces at work.
string theXml =
#"true1";
//string theXml = #"true1";
XDocument xmlElements = XDocument.Parse( theXml );
XNamespace ns = "http://myvalue.com";
XNamespace nsa = "http://schemas.datacontract.org/2004/07/My.Namespace";
var elements = from data in xmlElements.Descendants( ns + "Result" )
select new
{
TheBool = (bool) data.Element( nsa + "TheBool" ),
TheId = (int) data.Element( nsa + "TheId" ),
};
foreach ( var element in elements )
{
Console.WriteLine( element.TheBool );
Console.WriteLine( element.TheId );
}
Notice the use of ns in Descendants and nsa in Elements

You can pass an XName with a namespace to Descendants() and Element(). When you pass a string to Descendants(), it is implicitly converted to an XName with no namespace.
To create a XName in a namespace, you create a XNamespace and concatenate it to the element local-name (a string).
XNamespace ns = "http://myvalue.com";
XNamespace nsa = "http://schemas.datacontract.org/2004/07/My.Namespace";
var elements = from data in xmlElements.Descendants( ns + "Result")
select new
{
TheBool = (bool)data.Element( nsa + "TheBool"),
TheId = (int)data.Element( nsa + "TheId"),
};
There is also a shorthand form for creating a XName with a namespace via implicit conversion from string.
var elements = from data in xmlElements.Descendants("{http://myvalue.com}Result")
select new
{
TheBool = (bool)data.Element("{http://schemas.datacontract.org/2004/07/My.Namespace}TheBool"),
TheId = (int)data.Element("{http://schemas.datacontract.org/2004/07/My.Namespace}TheId"),
};
Alternatively, you could query against XElement.Name.LocalName.
var elements = from data in xmlElements.Descendants()
where data.Name.LocalName == "Result"

I have several namespaces listed at the top of an XML document, I don't really care about which elements are from which namespace. I just want to get the elements by their names. I've written this extension method.
/// <summary>
/// A list of XElement descendent elements with the supplied local name (ignoring any namespace), or null if the element is not found.
/// </summary>
public static IEnumerable<XElement> FindDescendants(this XElement likeThis, string elementName) {
var result = likeThis.Descendants().Where(ele=>ele.Name.LocalName==elementName);
return result;
}

I found the following code to work fine for reading attributes with namespaces in VB.NET:
MyXElement.Attribute(MyXElement.GetNamespaceOfPrefix("YOUR_NAMESPACE_HERE") + "YOUR_ATTRIB_NAME")
Hope this helps someone down the road.