C# parse xml with namescape fails

Question

I am trying to get the value out of the aa:ConfigurationID. But I can't seem to get the namespaces right. I always get the error:

System.Xml.XPath.XPathException: Namespace Manager or XsltContext needed. This query has a prefix, variable, or user-defined function

This is the XML:

<?xml version="1.0" encoding="UTF-8"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://www.w3.org/2003/05/soap-envelope"
    xmlns:aa="http://www.axis.com/vapix/ws/action1">
    <SOAP-ENV:Header></SOAP-ENV:Header>
    <SOAP-ENV:Body>
        <aa:AddActionConfigurationResponse>
            <aa:ConfigurationID>4</aa:ConfigurationID>
        </aa:AddActionConfigurationResponse>
    </SOAP-ENV:Body>
</SOAP-ENV:Envelope>

And this is my code:

string xml = @"<?xml version=""1.0"" encoding=""UTF-8""?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV=""http://www.w3.org/2003/05/soap-envelope""
    xmlns:aa=""http://www.axis.com/vapix/ws/action1"">
    <SOAP-ENV:Header></SOAP-ENV:Header>
    <SOAP-ENV:Body>
        <aa:AddActionConfigurationResponse>
            <aa:ConfigurationID>4</aa:ConfigurationID>
        </aa:AddActionConfigurationResponse>
    </SOAP-ENV:Body>
</SOAP-ENV:Envelope>";

XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(xml);

var nsmgr = new XmlNamespaceManager(xmlDoc.NameTable);
nsmgr.AddNamespace("SOAP-ENV", "http://www.w3.org/2003/05/soap-envelope");
nsmgr.AddNamespace("aa", "http://www.axis.com/vapix/ws/action1");
            
var node = xmlDoc.DocumentElement.SelectSingleNode("SOAP-ENV:Envelope/SOAP-ENV:Body/aa:AddActionConfigurationResponse/aa:ConfigurationID").InnerText;
Console.WriteLine(node);

I want to get the configurationID which is 4.

`.SelectSingleNode("/SOAP-ENV...", nsmgr)` - add `nsmgr` parameter and `/` to xpath. — Alexander Petrov, Feb 22 '23 at 13:38
Do you *have* to use `XmlDocument`? If you can use LINQ to XML (`XDocument` etc) that has much simpler namespace support. — Jon Skeet, Feb 22 '23 at 13:57
Try this: `var node = xmlDoc.DocumentElement.SelectSingleNode("SOAP-ENV:Body/aa:AddActionConfigurationResponse/aa:ConfigurationID", nsmgr).InnerText;` — Oleg Nesterov, Feb 22 '23 at 13:58
Why are you handling a soap message manually? Don't you have a client that deals with all of this and gives you deserialized data? — Fildor, Feb 22 '23 at 14:19
The following may be helpful: https://stackoverflow.com/a/75315612/10024425 — Tu deschizi eu inchid, Feb 22 '23 at 16:16

score 1 · Accepted Answer · answered Feb 24 '23 at 12:09

the problems was not adding the nsmgr after the path in SelectSingleNode, as explained in the comments.

correct way: var node = xmlDoc.DocumentElement.SelectSingleNode("SOAP-ENV:Envelope/SOAP-ENV:Body/aa:AddActionConfigurationResponse/aa:ConfigurationID",nsmgr).InnerText;

C# parse xml with namescape fails

1 Answers1