Read first root node from XML - c#

I work with three kinds of XML files :
Type A:
<?xml version="1.0" encoding="UTF-8"?>
<nfeProc versao="2.00" xmlns="http://www.portalfiscal.inf.br/nfe">
</nfeProc>
Tyepe B:
<?xml version="1.0" encoding="UTF-8"?>
<cancCTe xmlns="http://www.portalfiscal.inf.br/cte" versao="1.04">
</cancCTe>
Type C:]
<?xml version="1.0" encoding="UTF-8"?>
<cteProc xmlns="http://www.portalfiscal.inf.br/cte" versao="1.04">
</cteProc>
I have try with this code to read the first node :
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(#"C:\crruopto\135120068964590_v01.04-procCTe.xml");
XmlNodeList ml = xmlDoc.GetElementsByTagName("*");
XmlElement root = xmlDoc.DocumentElement;
exti = root.ToString();
but dont return anything i want to read the first node , need to know if the file is nfeProc ,canCTE or cteProc
The second question is how i get the value from "value" in the same tag???
Thanks

From this post:
//Root node is the DocumentElement property of XmlDocument
XmlElement root = xmlDoc.DocumentElement
//If you only have the node, you can get the root node by
XmlElement root = xmlNode.OwnerDocument.DocumentElement

I would suggest using XPath. Here's an example where I read in the XML content from a locally stored string and select whatever the first node under the root is:
XmlDocument doc = new XmlDocument();
doc.Load(new StringReader(xml));
XmlNode node = doc.SelectSingleNode("(/*)");

If you aren't required to use the XmlDocument stuff, then Linq is your friend.
XDocument doc = XDocument.Load(#"C:\crruopto\135120068964590_v01.04-procCTe.xml");
XElement first = doc.GetDescendants().FirstOrDefault();
if(first != null)
{
//first.Name will be either nfeProc, canCTE or cteProc.
}

Working with Linq to XML is the newest and most powerful way of working with XML in .NET and offers you a lot more power and flexibility than things like XmlDocument and XmlNode.
Getting the root node is very simple:
XDocument doc = XDocument.Load(#"C:\crruopto\135120068964590_v01.04-procCTe.xml");
Console.WriteLine(doc.Root.Name.ToString());
Once you have constructed an XDocument you don't need to use any LINQ querying or special checking. You simply pull the Root property from the XDocument.

Thanks i have solved this way the first part
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(nomear);
XmlNodeList ml = xmlDoc.GetElementsByTagName("*");
XmlNode primer = xmlDoc.DocumentElement;
exti = primer.Name;

First, to be clear, you're asking about the root element, not the root node.
You can use an XmlReader to avoid having to load large documents completely into memory. See my answer to a how to find the root element at https://stackoverflow.com/a/60642354/1307074.
Second, once the reader is referencing the element, you can use the reader's Name property to get the qualified tag name of the element. You can get the value as a string using the Value property.

Related

Extracting objects from xml that uses node prefixes using xpath

I have the following XML in a file called C:\temp\config.xml:
<?xml version="1.0" encoding="utf-8"?>
<dvp:systemConfig xmlns:devop="urn:foo.com:sys:rules">
<dvp:map id="rootFolderMap">
<dvp:entry key="anything" value="folder1"/>
<dvp:entry key="config" value="folder2"/>
<dvp:defaultValue value="folder1" />
</dvp:map>
<dvp:map id="folderMappings">
<dvp:entry key="SYS" value="System" />
<dvp:entry key="OPS" value="Operations" />
<dvp:entry key="DEV" value="Development" />
<dvp:defaultValue value="Miscellaneous" />
</dvp:map>
</dvp:systemConfig>
I am now trying to write C# code that will extract values from this XML. In particular, the list of value properties in the nodes.
List<string> folderNames = new List<string>
XmlDocument doc = new XmlDocument();
doc.Load(#"C:\temp\config.xml");
XmlNamespaceManager nsMgr = new XmlNamespaceManager(doc.NameTable);
XmlNodeList xmlNodeList =
doc.SelectNodes("/systemConfig/map[#id='folderMappings']/entry",nsMgr);
foreach (XmlNode xmlNode in xmlNodeList)
{
// I'm hoping xmlNodeList now contains a list of <dvp:entry> nodes.
string folderName = xmlNode.Attributes["value"].ToString().Trim();
folderNames.Add(folderName);
}
However, this code returns an empty xmlNodeList, so the final loop has no items.
I'm not sure how to use the XmlNamespaceManager to pick up the "dvp" prefix, or whether it figures this out when it loads the XmlDocument from the XML on disk.
Can anyone give me some guidance how one goes about using xpath to retrieve values for xml with prefixed nodes? Unfortunately I do not have the power to change the format of the XML so I have to work with the xml I'm provided with.
thanks heaps,
David.
you can ignore the namespace using local-name()
XmlNodeList xmlNodeList =
doc.SelectNodes("/*[local-name()='systemConfig']/*[local-name()='map'][#id='folderMappings']");

How to get data from an XML File in C# using XMLDocument class?

Good Evening All, and happy weekend!.
I have been trying all day to understand how to parse my simple XML file so I can understand it enough to write a personal project I want to work on.
I have been reading articles on this site and others but cannot get past where I am :(
My XML Document is ...
<XML>
<User>
<ID>123456789</ID>
<Device>My PC</Device>
</User>
<History>
<CreationTime>27 June 2013</CreationTime>
<UpdatedTime>29 June 2013</UpdatedTime>
<LastUsage>30 June 2013</LastUsage>
<UsageCount>103</UsageCount>
</History>
<Configuration>
<Name>Test Item</Name>
<Details>READ ME</Details>
<Enabled>true</Enabled>
</Configuration>
</XML>
I am trying to get the value in the details element (READ ME). Below is my code
// Start Logging Progress
Console.WriteLine("Test Application - XML Parsing and Creating");
Console.ReadKey();
// Load XML Document
XmlDocument MyDoc = new XmlDocument(); MyDoc.Load(#"E:\MyXML.XML");
// Select Node
XmlNode MyNode = MyDoc.SelectSingleNode("XML/Configuration/Details");
// Output Node Value
Console.WriteLine(String.Concat("Details: ", MyNode.Value));
// Pause
Console.ReadKey();
My console application is running and outputing "Target: " but not giving me the detail within the element.
Can somebody see why this is happening, and perhaps give me advice if I am completely off the wheel? I have no previous knowledge in reading XML files; hence where I am now :)
Thanks! Tom
With the your XPATH expression
// Select Node
XmlNode MyNode = MyDoc.SelectSingleNode("XML/Configuration/Details");
your are selection an element so the type of the MyNode will be XmlElement but the Value of an XmlElement is always null (see on MSDN) so you need to use XmlElement.InnerText or XmlElement.InnerXml isntead.
So the changed your code to
// Output Node Value
Console.WriteLine(String.Concat("Details: ", MyNode.InnerText));
Or you can select the content of an element with using the XPATH text() function, in this case MyNode will be XmlText where you get its value with Value:
// Select Node
XmlNode MyNode = MyDoc.SelectSingleNode("XML/Configuration/Details/text()");
// Output Node Value
Console.WriteLine(String.Concat("Details: ", MyNode.Value));
As a sidenote if you are anyway learning XML manipulation in C# you should check out LINQ to XML which is another/newer way to working with XML in C#.
Just for interest, a little-known "simple" syntax is this:
XmlDocument myDoc = new XmlDocument();
myDoc.Load(#"D:\MyXML.XML");
string details = myDoc["XML"]["Configuration"]["Details"].InnerText;
Note that this (and the XPath approach) could go pop if your XML doesn't conform to the structure you're expecting, so you'd ideally put some validation in there as well.
U can use Xpath library for that (u must include "System.Xml.XPath"):
XmlDocument document = new XmlDocument();
document.Load("MyXml.xml");
XPathNavigator navigator = document.CreateNavigator();
foreach (XPathNavigator nav in navigator.Select("//Details"))
{
Console.WriteLine(nav.Value);
}
the above code iterate over every node called (Details) extracting information and print it.
If you want to retrieve a particular value from an XML file
XmlDocument _LocalInfo_Xml = new XmlDocument();
_LocalInfo_Xml.Load(fileName);
XmlElement _XmlElement;
_XmlElement = _LocalInfo_Xml.GetElementsByTagName("UserId")[0] as XmlElement;
string Value = _XmlElement.InnerText;
Value contains the text value

NodeList.SelectSingleNode() syntax

Having problems getting NodeList.SelectSingleNode() to work properly.
My XML looks like this:
<?xml version="1.0" encoding="ISO-8859-1" standalone="yes"?>
<inm:Results xmlns:inm="http://www.namespace.com/1.0">
<inm:Recordset setCount="18254">
<inm:Record setEntry="0">
<!-- snip -->
<inm:Image>fileName.jpg</inm:Image>
</inm:Record>
</inm:Recordset>
</inm:Results>
The data is a long series of <inm:Record> entries.
I open the doc and get create a NodeList object based on "inm:Record". This works great.
XmlDocument xdoc = new XmlDocument();
xdoc.Load(openFileDialog1.FileName);
XmlNodeList xRecord = xdoc.GetElementsByTagName("inm:Record");
I start looping through the NodeList using a for loop. Before I process a given entry, I want to check and see if the <inm:Image> is set. I thought it would be super easy just to do
string strImage = xRecord[i].SelectSingleNode("inm:Image").InnerText;
My thinking being, "For the XRecord that I'm on, go find the <inm:Image> value ...But this doesn't work as I get the exception saying that I need a XmlNameSpaceManager. So, I tried to set that up but could never get the syntax right.
Can someone show me how to use the correct XmlNameSpaceManager syntax in this case.
I've worked around the issue for now by looping through all of the childNodes for a given xRecord, and checking the tag once I loop around to it. I would like to check that value first to see if I need to loop over that <inm:Record> entry at all.
No need to loop through all the Record elements, just use XPath to specify the subset that you want:
XmlDocument xdoc = new XmlDocument();
xdoc.Load(openFileDialog1.FileName);
XmlNamespaceManager manager = new XmlNamespaceManager(xdoc.NameTable);
manager.AddNamespace("inm", "http://www.inmagic.com/webpublisher/query");
XmlNodeList nodes = xdoc.SelectNodes("/inm:Results/inm:Recordset/inm:Record[inm:Image != '']", manager);
Using the LINQ to XML libraries, here's an example for retrieving that said node's value:
XDocument doc = XDocument.Load(openFileDialog1.FileName);
List<XElement> docElements = doc.Elements().ToList();
XElement results = docElements.Elements().Where(
ele => ele.Name.LocalName == "Results").First();
XElement firstRecord = results.Elements().Where(
ele => ele.Name.LocalName == "Record").First();
XElement recordImage = firstRecord .Elements().Where(
ele => ele.Name.LocalName == "Image").First();
string imageName = recordImage.Value;
Also, by the way, using Hungarian notation for a type-checked language is overkill. You don't need to prepend string variables with str when it will always be a string.
XmlNamespaceManager nsMgr = new XmlNamespaceManager(xdoc.NameTable);
string strImage = xRecord[i].SelectSingleNode("inm:Image",nsMgr).InnerText;
Should do it.
Using this Xml library, you can get all the records that have an Image child element with this:
XElement root = XElement.Load(openFileDialog1.FileName);
XElement[] records = root.XPath("//Record[Image]").ToArray();
If you want to be sure that the Image child contains a value, it can be expressed like this:
XElement[] records = root.XPath("//Record[Image != '']").ToArray();

XmlDocument.SelectNodes question

What's the difference using root node to select and using document object to select nodes?
Which way is preferred.
For example,
1.
XmlDocument Doc = new XmlDocument();
Doc.Load(mem);
XmlNodeList nodeList = Doc.SelectNodes(#"//#id");
2.
XmlDocument Doc = new XmlDocument();
Doc.Load(mem);
XmlElement root = Doc.DocumentElement;
XmlNodeList nodeList = root.SelectNodes(#"//#id");
In fact, I never got any differences. And use just
Doc.SelectNodes(#"//#id");
because if document's root exists
bool b = Doc.OuterXml == Doc.DocumentElement.OuterXml; // true
Since XPath's // expression always matches from the document root, the result will be the same whether you start from the document root or from its documentElement.
So I guess you're better off using the shorter Doc.SelectNodes("//#id"); syntax.
The root of an XML document contains its document element at least, but it may also contain processing instructions and comments. For instance, in this XML document:
<!-- This is a child of the root -->
<document_element>
<!-- This is a child of the document element -->
<document_element>
<!-- This is also a child of the root -->
the root has three child nodes, one of which is its top-level element. In this case, this:
XmlNodeList comments = doc.SelectNodes("comment()");
and this:
XmlNodeList comments = doc.DocumentElement.SelectNodes("comment()");
return totally different results.

XPath doesn't work as desired in C#

My code doesn't return the node
XmlDocument xml = new XmlDocument();
xml.InnerXml = text;
XmlNode node_ = xml.SelectSingleNode(node);
return node_.InnerText; // node_ = null !
I'm pretty sure my XML and Xpath are correct.
My Xpath : /ItemLookupResponse/OperationRequest/RequestId
My XML :
<?xml version="1.0"?>
<ItemLookupResponse xmlns="http://webservices.amazon.com/AWSECommerceService/2005-10-05">
<OperationRequest>
<RequestId>xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxxx</RequestId>
<!-- the rest of the xml is irrelevant -->
</OperationRequest>
</ItemLookupResponse>
The node my XPath returns is always null for some reason. Can someone help?
Your XPath is almost correct - it just doesn't take into account the default XML namespace on the root node!
<ItemLookupResponse
xmlns="http://webservices.amazon.com/AWSECommerceService/2005-10-05">
*** you need to respect this namespace ***
You need to take that into account and change your code like this:
XmlDocument xml = new XmlDocument();
xml.InnerXml = text;
XmlNamespaceManager nsmgr = new XmlNamespaceManager(xml.NameTable);
nsmgr.AddNamespace("x", "http://webservices.amazon.com/AWSECommerceService/2005-10-05");
XmlNode node_ = xml.SelectSingleNode(node, nsmgr);
And then your XPath ought to be:
/x:ItemLookupResponse/x:OperationRequest/x:RequestId
Now, your node_.InnerText should definitely not be NULL anymore!
Sorry for the late reply but I had a similar problem just a moment ago.
if you REALLY want to ignore that namespace then just delete it from the string you use to initialise the XmlDocument
text=text.Replace(
"<ItemLookupResponse xmlns=\"http://webservices.amazon.com/AWSECommerceService/2005-10-05\">",
"<ItemLookupResponse>");
XmlDocument xml = new XmlDocument();
xml.InnerXml = text;
XmlNode node_ = xml.SelectSingleNode(node);
return node_.InnerText;

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