Why is my xml doc considered an element? - c#

I am trying to load an xml file into an xmlDocument but receive an error that it cannot cast the xmlelement to a xmldocument why?
XML
<VR>
<SubscriberID>xxxx</SubscriberID>
<EmailAddress>m#gmail.com</EmailAddress>
<FirstName>m</FirstName>
<LastName>x</LastName>
<State>CO</State>
<Country/>
<BirthDate>11/16/3004</BirthDate>
<SendEmail>False</SendEmail>
<Preference Value="true" Key="life"/>
<Preference Value="true" Key="yo"/>
</VR>
C# Test
preferenceHelper target = new preferenceHelper(); // TODO: Initialize to an appropriate value
XmlDocument docIn = new XmlDocument();
docIn.Load(#"C:/INTG/trunk/src/VRI.Integration.Email/Test/xmlIn.xml");
XmlDocument expected = null; // I know this will fail in the test, but it should compile, right?
XmlDocument actual;
actual = target.preferencesXmlDoc(docIn);
Assert.AreEqual(expected, actual);
Assert.Inconclusive("Verify the correctness of this test method.");
C# function:
public class preferenceHelper
{
public preferenceHelper() { }
XmlDocument docOut = new XmlDocument();
public XmlDocument preferencesXmlDoc(XmlDocument docIn)
{
foreach (XmlDocument root in docIn.SelectNodes("//VR"))
{
foreach (XmlDocument node in root.SelectNodes("//Preference"))
{
XmlNode Name = docIn.CreateElement("Name");
Name.InnerText = node.InnerText = node.Attributes["Key"].Value;
XmlNode Value = docIn.CreateElement("Value");
Value.InnerText = node.InnerText = node.Attributes["Value"].Value;
docOut.CreateElement("Property").AppendChild(Name).AppendChild(Value);
}
}
return docOut;
}
}
Error
Test method Test.preferenceHelperTest.preferencesXmlDocTest threw exception:
System.InvalidCastException: Unable to cast object of type 'System.Xml.XmlElement' to type 'System.Xml.XmlDocument'.
I will not be adding a namespace to the xmlIn, if this is required - how might I load in my xml File?
Where it fails: actual = target.preferencesXmlDoc(docIn);
Thanks

Your problems are in these statements:
foreach (XmlDocument root in SelectNodes(...))
foreach implicitly casts each value in the sequence to the type you specify. The statement is expanded to:
using(var e = sequence.GetEnumerator())
{
while (e.MoveNext())
{
XmlDocument v = (XmlDocument)e.Current;
// loop body
}
}
The reason this is crashing with an InvalidCastException is that the type of node you're selecting is XmlElement, not XmlDocument. To fix the issue, simply switch the type in your foreach statement to XmlElement.
You can also improve readability by using XPath to reach the Preference elements, replacing both loops with a single:
foreach (XmlElement node in docIn.SelectNodes("/VR/Preference"))
Your outer SelectNodes loop is actually completely redundant because //Preference will get all Preference descendants from the root of the document already, not just from that specific child VR.

The proplem is here:
foreach (XmlDocument root in docIn.SelectNodes("//VR"))
and here:
foreach (XmlDocument node in root.SelectNodes("//Preference"))
XmlNode.SelectNodes() returns an XmlNodeList, which is an IEnumerable of XmlNodes. It will not contain any XmlDocuments.
So do this:
foreach (XmlNode root in docIn.SelectNodes("//VR"))
and this:
foreach (XmlElement node in root.SelectNodes("//Preference"))

XmlDocument.SelectNodes("//VR") returns an XmlNodeList, not an XmlDocument. So at the least you need to change your code to:
public XmlDocument preferencesXmlDoc(XmlDocument docIn)
{
foreach (XmlNode root in docIn.SelectNodes("//VR"))
{
foreach (XmlNode node in root.SelectNodes("//Preference"))
{

A document usually has a header:
<?xml version="1.0"?>
Without the header it is considered an element.
Try adding one.

Related

Failing to read value XML attribute in C#

I am trying to read a file produced by another developer. The file looks something like this. I am trying to read in the value for 'ProfileName', but when I look at the object in memory, I see null for the Value (capital V) attribute. The only place I can see the string "GolfLeague-Dual" is in the outerxml attribute, but I would have to parse through a bunch of just to get it.
<?xml version="1.0"?>
<TopNode>
<ProfileSettings>
<ProfileName value="GolfLeague-Dual" />
</ProfileSettings>
</TopNode>
Here is my code to try to read this:
XmlDocument doc = new XmlDocument();
doc.Load(directory + #"\Settings.xml");
XmlElement root = doc.DocumentElement;
XmlNodeList nodes = root.SelectNodes("//ProfileSettings");
foreach (XmlNode node in nodes) {
Console.WriteLine(node["ProfileName"].Value);
}
Your code is trying to get the inner value of the node, not an attribute called value. Try this instead...
foreach (XmlNode node in nodes) {
Console.WriteLine(node["ProfileName"].Attributes["value"].Value);
}
Here's a working dotnetfiddle...
https://dotnetfiddle.net/pmJKbX

Pasting xml to console

I need to get data SHILS_V from XML file. I read .xml
XML code for example:
<SVED_PR_GS>
<ZGLV>
<VERSION>99</VERSION>
<DATA>9999</DATA>
<FILENAME>1234</FILENAME>
<FIRSTNAME>1234</FIRSTNAME>
</ZGLV>
<SVD>
<CODE></CODE>
<YEAR></YEAR>
<MONTH></MONTH>
</SVD>
<SV_PR_GS>
<OBSV>
<N_ZAP>1</N_ZAP>
<MO_SV_V>12345</MO_SV_V>
<SNILS_V>123456789</SNILS_V>
</OBSV>
</SV_PR_GS>
</SVED_PR_GS>
My code to read xml:
XmlDocument xml = new XmlDocument();
xml.Load(filename);
Console.WriteLine("this");
XmlNodeList nodes = xml.GetElementsByTagName("SVED_PR_GS/SV_PR_GS");
foreach (XmlNode n in nodes)
{
Console.WriteLine("in loop");
XmlNode snils_v = n["OBSV/SNILS_V"];
Console.WriteLine("Snils V: " + snils_v);
}
Where is the problem?
How to get the information from SNILS_V?
GetElementsByTagName expects a tagname, not an XPath expression, "SV_PR_GS" will work there. And the same goes for the indexer of your XmlNode instance called n, this XPath will not work n["OBSV/SNILS_V"], use a tagname there as well but you have to handle the extra OBSV child there.
Here is your adapted code that produces output for me:
XmlNodeList nodes = xml.GetElementsByTagName("SV_PR_GS");
foreach (XmlNode n in nodes)
{
Console.WriteLine("in loop");
// first get the OBSV element
XmlNode obsv = n["OBSV"];
// now we can reach the other childs
XmlNode snils_v = obsv["SNILS_V"];
// Value will be null for XmlElement types, use InnerText instead
Console.WriteLine("Snils V: {0}" , snils_v.InnerText);
}
Notice that the Value property will return null for XmlNode that are of type XmlElement. In the XmlNode.Value documentation it is stated:
null. You can use the XmlElement.InnerText or XmlElement.InnerXml properties to access the value of the element node.
As your SNILS_V element seem to contain just a value InnerText is appropriate here.
To select a single node from XML. You need to access that object using SelectSingleNode method.
xml.SelectSingleNode("xpath for node")
To get collection of nodes you can write
xml.SelectNodes("xpath for node collection")
You should be able to get the value as follows:
XmlDocument xml = new XmlDocument();
xml.Load(filename);
Console.WriteLine("this");
XmlNodeList nodes = xml.GetElementsByTagName("OBSV");
foreach (XmlNode n in nodes)
{
Console.WriteLine("in loop");
XmlNode snils_v = n.SelectSingleNode("SNILS_V");
Console.WriteLine("Snils V: " + snils_v.InnerText);
}

EnsureLocalDisposalRule for XmlNodeList

When I run Gendarme 2.11 on my C#.NET project the following code triggers the EnsureLocalDisposalRule:
XmlDocument myXmlDoc = this.GetXmlDoc();
foreach (XmlNode myNode in myXmlDoc.GetElementsByTagName("TAGNAME"))
{
... does something with myNode ...
}
with the message:
Local of type 'XmlNodeList' is not disposed of (at least not locally).
After reading the rule description
I attempted to rewrite it as follows:
XmlDocument myXmlDoc = this.GetXmlDoc();
using (XmlNodeList myNodeList = myXmlDoc.GetElementsByTagName("TAGNAME"))
{
foreach (XmlNode myNode in myNodeList )
{
... does something with myNode ...
}
}
but this gives the error:
'System.Xml.XmlNodeList': type used in a using statement must be
implicitly convertible to 'System.IDisposable'
What is causing this? Is this a bug in Gendarme? Or have I misunderstood the rule? How could my code be improved?

Get Child Nodes from an XML File

I have an XML File like below
<Attachment>
<FileName>Perimeter SRS.docx</FileName>
<FileSize>15572</FileSize>
<ActivityName>ActivityNamePerimeter SRS.docx</ActivityName>
<UserAlias>JameelM</UserAlias>
<DocumentTransferId>7123eb83-d768-4a58-be46-0dfaf1297b97</DocumentTransferId>
<EngagementName>EAuditEngagementNameNew</EngagementName>
<Sender>JameelM#orioninc.com</Sender>
</Attachment>
I read these xml file like below
var doc = new XmlDocument();
doc.Load(files);
foreach (XmlElement pointCoord in doc.SelectNodes("/Attachment"))
{
}
I need to get each child node value inside the Attachment node. How can i get these xml elements from the xml node list?
I need to get each child node value inside the Attachment node.
Your question is very unclear, but it looks like it's as simple as:
foreach (XmlNode node in doc.DocumentElement.ChildNodes)
{
}
After all, in the document you've shown us, the Attachment is the document element. No XPath is required.
As an aside, if you're using .NET 3.5 or higher, LINQ to XML is a much nicer XML API than the old DOM (XmlDocument etc) API.
try this
var data = from item in doc.Descendants("Attachment")
select new
{
FileName= item.Element("FileName").Value,
FileSize= item.Element("FileSize").Value,
Sender= item.Element("Sender").Value
};
foreach (var p in data)
Console.WriteLine(p.ToString());
var doc = new XmlDocument();
doc.Load(files);
foreach (XmlElement pointCoord in doc.SelectNodes("/Attachment"))
{
if(pointCoord!=null)
{
var valueOfElement=pointCoord.InnerText;
}
}
if you want to run conditional logic against the element names (UserAlias, etc) then use the Name property of the XmlElement.

Overwrite specific XML attributes

Let's say I have a file like this:
<outer>
<inner>
<nodex attr="value1">text</attr>
<nodex attr="value2">text</attr>
</inner>
</outer>
Basically what I want to do is, in C# (constrained to .net 2.0 here), this (pseudocode):
foreach node
if(node eq 'nodex')
update attr to newvalue
When complete, the xml file (on disk) should look like:
<outer>
<inner>
<nodex attr="newvalue1">text</attr>
<nodex attr="newvalue2">text</attr>
</inner>
</outer>
These two look marginally promising:
Overwrite a xml file value
Setting attributes in an XML document
But it's unclear whether or not they actually answer my question.
I've written this code in the meantime:
Here's a more minimal case which works:
public static void UpdateXML()
{
XmlDocument doc = new XmlDocument();
using (XmlReader reader = XmlReader.Create("XMLFile1.xml"))
{
doc.Load(reader);
XmlNodeList list = doc.GetElementsByTagName("nodex");
foreach (XmlNode node in list)
{
node.Attributes["attr"].Value = "newvalue";
}
}
using (XmlWriter writer = XmlWriter.Create("XMLFile1.xml"))
{
doc.Save(writer);
}
}
The fastest solution would be to use a loop with XmlTextReader/XmlTextWriter. That way you do not need to load the whole xml in memory.
In pseudocode:
while (reader.read)
{
if (reader.Node.Name == "nodex")
......
writer.write ...
}
You can check here for ideas.
Here is a sample script that can be run from LinqPad
var x = #"<outer>
<inner>
<nodex attr=""value1"">text</nodex>
<nodex attr=""value2"">text</nodex>
</inner>
</outer>";
XmlDocument doc = new XmlDocument();
doc.LoadXml(x);
foreach (XmlNode n in doc.SelectNodes("//nodex"))
{
n.Attributes["attr"].Value = "new" + n.Attributes["attr"].Value.ToString();
}
doc.OuterXml.Dump();
As starting point you can show us what you have tried, you could use XPATH to select the nodes you want to modify, search for select node by attribute value in xpath.
After you have found the nodes you want to update you can reassign the attribute value as needed with a normal assignment.

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