How to get element data from Soap Web Response? VB.NET

Question

I'm trying to get data from a webservice, returning just one result, the number of a given item in stock.

I'm successfully getting a result, but need to strip all the XML code from it to simple return the number, the XML being returned looks like:

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <stockenquiryResponse xmlns="https://webservices.electrovision.co.uk">
      <stockenquiryResult>**THE NUMBER I NEED**</stockenquiryResult>
    </stockenquiryResponse>
  </soap:Body>
</soap:Envelope>

I'm sure this has been asked many times, but I can't find a simple solution to just get the value from the stockenquiryresult tag.

get value from XML in vbnet

Seems like the right answer, but I can't get it to work.

If it helps, I am getting the data using the example from :

http://msdn.microsoft.com/en-us/library/debx8sh9(v=vs.80).aspx

With just a couple of tweaks to get the data correctly, most notably changing the content type to application/soap+xml and passing the data as XML.

I am using VB with ASP.NET 2.0.

Answer 1

There are some built in .NET classes that you can use to read XML.

Using XmlDocument

XmlDocument exposes the XML string you retrieved from the web service in a DOM (Document Object Model). You can read about XmlDocument on MSDN.

Dim XMLDoc as new XMLDocument

XMLDoc.LoadXML(XMLString)

Dim Result as string = XMLDoc.LastChild.InnerText

'Alternatively, you can use SelectSingleNode.
'You will need to determine the correct XPath expression.
'Dim Result as string = XMLDoc.SelectSingleNode("XPathToNode").InnerText

If you choose to use SelectSingleNode, the XPath documentation on MSDN will come in handy.

Using XmlReader

For something as quick as reading one tag, you may also use an XmlReader (MSDN Documentation). Unlike XmlDocument, XmlReader does not expose the XML as a DOM. XmlReader is a forward only reader, but should be faster and more lightweight than XmlDocument. This works fine for situations such as yours.

Dim XSettings as new XmlReaderSettings
'You can use XSettings to set specific settings on the XmlReader below.
'See linked docs.

Using SReader as New StringReader(XMLString)

    Dim X as XmlReader = XmlReader.Create(SReader, XSettings)
    X.ReadToDescendant("stockenquiryResult")
    Dim Result as string = X.ReadElementContentAsString

End Using