asked on

Reading an XML file using VB.Net

Hi Experts,

I'm trying to read an XML file with using VB.Net code.

I've got the following little test XML file:

<RootNode>
<PersonalDetails>
       <FirstName>Kosie </FirstName>
       <LastName>Venter</LastName>
       <CellPhone>082-416-8703</CellPhone>
       <EMail>kosie@kosieInc.co.za</EMail>
</PersonalDetails>
</RootNode>

I also have the following VB code:

Dim XMLDoc As New Xml.XmlDocument
Dim XNode As Xml.XmlNode = Nothing

XMLDoc.Load(Me.txtXMLFile.Text)
XNode= XMLDoc.ChildNodes(0).ChildNodes(0) 'This should be FirstName

My problem is that:
XNode now contains the node <FirstName>Kosie </FirstName>

If I use XNode.Value, NOTHING is returned. I expected to get "Kosie".

What is wrong?

Thanks

SteveH_UK

You should use .InnerText or .InnerXml instead.

See http://msdn2.microsoft.com/en-us/library/system.xml.xmlnode.value(VS.71).aspx

PantoffelSlippers

ASKER

SteveH_UK,

I did try innertext but it returns the values of the node and all of its child nodes!

I'm looking to get the value of the single node only.

Any idea?

SteveH_UK

Firstly, remember that nodes are not elements. Rather, an XmlNode can be an element, an attribute, a CDATA section or a TEXT section, etc.

So when you use ChildNodes(0) it will be fine for now, but not if you later add attributes to the other elements.

Try using either of the following:

' First
  XMLDoc.Load(Me.txtXMLFile.Text)
  Dim FirstName As String
  FirstName = XMLDoc.ChildNodes(0).ChildNodes(0).InnerText
 
' Alternative
  XMLDoc.Load(Me.txtXMLFile.Text)
  Dim FirstName As String
  FirstName=XMLDoc.SelectSingleNode("/RootNode/PersonalDetails/FirstName").InnerText

Open in new window

PantoffelSlippers

ASKER

Thanks SteveH_UK,

Both method return the values of the firstname node and child nodes:

Copied this from my immediate window:

?xmldoc.SelectSingleNode("/RootNode/PersonalDetails/FirstName").InnerText
"Kosie
K"

?XMLDoc.ChildNodes(0).ChildNodes(0).InnerText
"Kosie
KVenter082-416-8703kosie@kosieInc.co.za"

Any other ideas?

Thanks

SteveH_UK

This looks to me like the file is not loading correctly. I'm surprised it's working at all!

Try doing a dump of XmlDoc.OuterXml. If you are using Visual Studio (Express) then put a breakpoint at this line and use F5 to launch debug. Then look at what is shown in the Locals window. You can then inspect the content of XmlDoc directly to see what different results offer. You can also use the Watch window to see what XmlDoc.ChildNodes(0) gives, for example.

PantoffelSlippers

ASKER

OuterXML looks this:

?xmldoc.OuterXml
"<RootNode><PersonalDetails><FirstName>Kosie
<Initials>K</Initials></FirstName><LastName>Venter</LastName><CellPhone>082-416-8703</CellPhone><EMail>kosie@kosieInc.co.za</EMail></PersonalDetails></RootNode>"

?RootNode.OuterXml
"<FirstName>Kosie
<Initials>K</Initials></FirstName>"

Anything else?

SteveH_UK

The XML above does not correspond with the XML you initially posted with this question. Therefore, you are getting a different result.

Why have you embedded the "Initials" tag inside the "FirstName" tag. Pull it out and this will solve the last query.

The e-mail issue is another question, but make sure your input XML is correct.

PantoffelSlippers

ASKER

SteveH_UK,

I added the Initials node to illustrate that the InnerText method on FirstName node does not only return the contents of the FirstName node but also the childnode's (Initials) contents.

On my initial post, you replied:
>>>You should use .InnerText or .InnerXml instead.

Thanks

Then I replied:
>>>>I did try innertext but it returns the values of the node and all of its child nodes!

I added the Initials node to illustrate this.

SteveH_UK

Ok. But because you didn't indicate that there was any inner nodes, I was answering a different question.

In this case you should append text() to the XPath, see http://www.w3schools.com/xpath/xpath_examples.asp.

XMLDoc.Load(Me.txtXMLFile.Text)
  Dim FirstName As String
  FirstName=XMLDoc.SelectSingleNode("/RootNode/PersonalDetails/FirstName/text()").InnerText

Open in new window

SteveH_UK

The text is actually a node, specifically a Text node, so you have to select the Text node within the containing Element node. This is what the text() XPath construct does. Note the similarity with attributes which are also XML nodes.

PantoffelSlippers

ASKER

Sorry SteveH_UK,

I don't follow that last statement. Could you please elaborate on that?

Thanks

SteveH_UK

Certainly.

Let's consider your XML. I've repeated it below, so we have the same XML in mind. I've also broken it down into the XmlNodes that represent it:

<RootNode>                                       XmlNode [Element]
  <PersonalDetails>                               XmlNode [Element]
        <FirstName>                                XmlNode [Element]
             Kosie                                  XmlNode [Text]
        </FirstName>                               ------- 
        <LastName>                                 XmlNode [Element]
             Venter                                 XmlNode [Text]
        </LastName>                                -------
        <CellPhone>                                XmlNode [CellPhone]
             082-416-8703                           XmlNode [Text]
        </CellPhone>                               -------
        <EMail>                                    XmlNode [Element]
             kosie@kosieInc.co.za                   XmlNode [Text]
        </EMail>                                   -------
  </PersonalDetails>                              -------
</RootNode>                                      -------

Open in new window

ASKER CERTIFIED SOLUTION

SteveH_UK

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SteveH_UK

Also see http://www.w3schools.com/dom/default.asp

PantoffelSlippers

ASKER

Thanks,

I'll have a look right away

PantoffelSlippers

ASKER

Thanks SteveH_UK. After reading through the content, I know more about nodes but I still don't know how to get the text out of a XML node with VB code...
Thanks for your effort - you guys have a tough job with newbies like me.