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Reading oddly-formatted XML file C#

I need some help with reading an oddly-formatted XML file. Because of the way the nodes and attributes are structured, I keep running into XMLException errors (at least, that's what the output window is telling me; my breakpoints refuse to fire so that I can check it). Anyway, here's the XML. Anyone experienced anything like this before?
<ApplicationMonitoring>
<MonitoredApps>
<Application>
<function1 listenPort="5000"/>
</Application>
<Application>
<function2 listenPort="6000"/>
</Application>
</MonitoredApps>
<MIBs>
<site1 location="test.mib"/>
</MIBs>
<Community value="public"/>
<proxyAgent listenPort="161" timeOut="2"/>
</ApplicationMonitoring>
Cheers
EDIT: Current version of the parsing code (file path shortened - Im not actually using this one):
XmlDocument xml = new XmlDocument();
xml.LoadXml(#"..\..\..\ApplicationMonitoring.xml");
string port = xml.DocumentElement["proxyAgent"].InnerText;

Your problem in loading the XML is that xml.LoadXml expects you to pass the xml document as a string, not a file reference.
Try instead using:
xml.Load(#"..\..\..\ApplicationMonitoring.xml");
Essentially in your original code you are telling it that your xml document is
..\..\..\ApplicationMonitoring.xml
And I'm sure you can now see why there is a parse exception. :) I've tested this with your xml document and the modified load and it works fine (except for the issue that Only Bolivian Here pointed out with the fact that your inner Text is not going to return anything.
For completeness you probably want:
XmlDocument xml = new XmlDocument();
xml.Load(#"..\..\..\ApplicationMonitoring.xml");
string port = xml.DocumentElement["proxyAgent"].Attributes["listenPort"].Value;
//And to get stuff more specifically in the tree something like this
string function1 = xml.SelectSingleNode("//function1").Attributes["listenPort"].Value;
Note the use of the Value property on the attribute and not the ToString method which won't do what you are expecting.
Exactly how you extract the data from the xml is probably dependant on what you are doing with it. For example you may want to get a list of Application nodes to enumerate over with a foreach by doing this xml.SelectNodes("//Application").
If you are having trouble with extdacting stuff though that is probably the scope of a different question since this was just about how to get the XML document loaded.

xml.DocumentElement["proxyAgent"].InnerText;
The proxyAgent element is self closing. InnerText will return the string inside of an XML element, in this case, there is no inner elements.
You need to access an attribute of the element, not the InnerText.

Try this:
string port = xml.GetElementsByTagName("ProxyAgent")[0].Attributes["listenPort"].ToString();
Or use Linq to XML:
http://msdn.microsoft.com/en-us/library/bb387098.aspx
And... your XML is not malformed...

xpath query to find the root element attribute value

Most of the time i was trying to write xpath query by myself and fails all the time :(. Again i got in to problem to find the value
here is my xml
<Tail xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" Id="45000061" CreateDateTime="2010-03-08T16:02:52.512+11:00" Type="Actual" Sender="DRNA" Receiver="Lawson">
Am trying to find the "ID" value in my root node (that's suppose to be "45000061")
Any help please.
Thanks in Advance

The xpath expression /Tail/#Id you get you the Id attribute value.

This site has a great free tool for building XPath Expressions (XPath Builder).
http://www.bubasoft.net/
Make your xpath expression work in the tool and then put it in your code.

Parsing a file containing xml elements in C#

I have a big xml file which is composed of multiple xml files. The file structure is like this.
<xml1>
</xml1>
<xml2>
</xml2>
<xml3>
</xml3>
.
.
<xmln>
</xmln>
I want to process each XML file by a LINQ statement but I am not sure how to extract each XML element individually from the file and continue the iteration until the end. I figured experts here would be able to give me the nudge I am looking for. My requirement is to extract the individual elements so i could load into a XDoc element for further processing and continue on through the subsequent elements. Any help on this would be greatly appreciated.
Thanks for reading!!

Assuming each element is a valid XML, you can wrap your document in a top-level tag and then load it just fine:
<wrap>
<xml1>
</xml1>
<xml2>
</xml2>
</wrap>

You can use the System.Xml reference, which includes a lot of built-in functionality, and it allows you to declare an XmlTextReader. More info here.

If this is an error log with individual well formed xml elements, you probably don't want to load it as an XMLDocument. A better option is to use an XPathDocument created with an XmlReader where the XmlReaderSettings specify ConformanceLevel.Fragment. Then you can use an XPathNavigator to access your elements and attributes as needed. See the third answer in this forum post for sample code.
...late by just a year and then some. :)

Best way to replace XML Text

I have a web service which returns the following XML:
<Validacion>
<Es_Valido>NK7+22XrSgJout+ZeCq5IA==</Es_Valido>
</Validacion>
<Estatus>
<Estatus>dqrQ7VtQmNFXmXmWlZTL7A==</Estatus>
</Estatus>
<Generales>
<Nombre>V4wb2/tq9tEHW80tFkS3knO8i4yTpJzh7Jqi9MxpVVE=</Nombre>
<Apellido>jXyRpjDQvsnzZz+wsq6b42amyTg2np0wckLmQjQx1rCJc8d3dDg6toSdSX200eGi</Apellido>
<Ident_Clie>IYbofEiD+wOCJ+ujYTUxgsWJTnGfVU+jcQyhzgQralM=</Ident_Clie> <Fec_Creacion>hMI2YyE5h2JVp8CupWfjLy24W7LstxgmlGoDYjPev0r8TUf2Tav9MBmA2Xd9Pe8c</Fec_Creacion>
<Nom_Asoc>CF/KXngDNY+nT99n1ITBJJDb08/wdou3e9znoVaCU3dlTQi/6EmceDHUbvAAvxsKH9MUeLtbCIzqpJq74e QfpA==</Nom_Asoc>
<Fec_Defuncion />
</Generales>
The text inside the tags in encrypted, I need to decrypt the text, I've come up with a regular expressions solution but I don't think it's very optimal, is there a better way to do this? thanks!

I wouldn't use a regular expression. Load the XML with something like LINQ to XML, find every element which just has a text child, and replace the contents of that child with the decrypted form.
Do you know which elements will be encrypted? That would make it even easier. Basically you'll want something along the lines of:
// It's possible that modifying elements while executing Descendants()
// would be okay, but I'm not sure
List<XElement> elements = doc.Descendants().ToList();
foreach (XElement element in elements)
{
if (ShouldDecrypt(element)) // Whatever this would do
{
element.Value = Decrypt(element.Value);
}
}
(I'm assuming you know how to do the actual decryption part, of course.)

Never ever use regular expressions to parse XML. XmlReader and XmlDocument, both found inside System.Xml, provide a way better way to parse XML.

Do you know the type of encryption used? Look here to get the basics on the Cryptology capabilities in .NET

Xpath, retrieving node value

I get this return value from Sharepoint... which I have just included the first part of the xml snippet...
<Result ID=\"1,New\" xmlns=\"http://schemas.microsoft.com/sharepoint/soap/\">
<ErrorCode>0x00000000</ErrorCode><ID /><z:row ows_ID=\"9\"
It populates a XmlNode node object.
How using xPath can I get the value of ows_id ?
My code so far...
XmlNode results = list.UpdateListItems("MySharePointList", batch);
Update
So far I have this : results.FirstChild.ChildNodes[2].Attributes["ows_ID"].Value
But I am not sure how reliable it is, can anyone improve on it?

I don't know if its necessarily an improvement, but it might be more readable, though more verbose:
/*[local-name() = 'Result']/*[local-name() = 'row']/#ows_ID
There is probably more to the fragment you posted so this XPath query might need a fixup when used against the actual xml result.
The function, local-name(), lets you ignore namespaces, which can be both a boon and a curse. :)

When you start from root:
/Result/z:row/#ows_ID
also you can improve search if exists multiple Result:
/Result[#ID='1,New']/z:row/#ows_ID

<xsl:value-of select="Result/b:row/#ows_ID"/>
or
<xsl:value-of select="Result/b:row[#ows_ID = '9']"/>
Depending on what value you wanted

You probably need to make sure the z namespace prefix is declared correctly - that's implementation dependent. Here's how you do it in Java's XPath implementation.
Then to select the value of the ows_ID attribute, you need to navigate to the element itself, then use #ows_ID to get the value.

The specific xpath calls depend on what library you use (e.g. libxml xpath implementation).
But the generic xpath statement would be:
"//z:row[#ows_ID='9']"
This will select all z:row nodes with an attribute ows_ID of value 9.
You can modify this query to match all z:row nodes or only those with a specific attribute.
For details look here: W3Schools XPath syntax