VB.net adding data in a selected node

saikoboarder · May 15th, 2008, 07:52 AM

I have a XML file with this structure. (many more users in it)

Code:

<users>
 <user>
    <counter>1000000</couter>
    <voornaam>Maarten Liesbet</voornaam>
    <achternaam>Verheyen</achternaam>
    <geslacht>M</geslacht>
    <nummerplaat>EEC-718</nummerplaat>
    <naam>test</naam>
    <adres>
    </adres>
    <email>
    </email>
    <telefoon>
    </telefoon>
    <sitebed>
    </sitebed>
    <datum>14/05/2008</datum>
    <uur>10:13:30</uur>
    <logoff>0:00:00</logoff>
    <kaartnummer>590258076812</kaartnummer>
  </user>
</users>

I have a form with a textfield. In the texfield a number can be entered. (counter)
and then I want the logoff time adjusted.
So the programme has to navigate to the correct node with the corresponding counternumber(xpath???) and then change the element "logoff" to the time of the moment (logoff = TimeOfDay)

Is this even possible ?
thanx in advance

samjudson · May 15th, 2008, 07:57 AM

Answer: Of course it is.

Assuming you have an XmlDocument containing the above document, then use SelectSingleNode to select the node with the correct counter, and then just update the text value of the logoff node.

/- Sam Judson : Wrox Technical Editor -/

Martin Honnen · May 15th, 2008, 07:59 AM

You can use System.Xml.XmlDocument to load your XML document and keep it in memory, then you can use XPath to find the logoff element:

Code:

Dim doc as New XmlDocument()
doc.Load("users.xml")


Dim logoff As XmlNode = doc.SelectSingleNode(String.Format("/users/user[counter = {0}]/logoff", textField.Text))
If logoff IsNot Nothing Then
  logoff.InnerText = ' get current time here
Else
  ' output message that there is no user with the counter
End If

--
Martin Honnen
Microsoft MVP - XML

saikoboarder · May 15th, 2008, 08:04 AM

Wow what a fast reply

I'm going to test it right away. and keep you posted

thx already

saikoboarder · May 15th, 2008, 08:45 AM

Sorry but it doest work.
I builded in 2 messageboxes.
First says's if the number does not exist.
and if I enter a wrong number the messagebox shows.
the second say's (your logged off)
and if I enter a correct number this messagebox comes up but in my XML file the element logoff stay's 0:00:00

no error message is shown

Martin Honnen · May 15th, 2008, 08:50 AM

Well XmlDocument is an in-memory object model.
The code I showed changes the logoff value in the object model.
To persist changes to a file you need to call

Code:

doc.Save("users.xml")

--
Martin Honnen
Microsoft MVP - XML

samjudson · May 15th, 2008, 08:51 AM

What doesn't work? You aren't showing us any code?

Are you saving the XML back to the file?

/- Sam Judson : Wrox Technical Editor -/

saikoboarder · May 15th, 2008, 08:55 AM

Quote:

quote:doc.Save("users.xml")

Quote:

I feel pretty stupid right now.
I've saved the file hundreds of times in other classes and here I forget it.

It works perfect.

Thanx very much

saikoboarder · May 16th, 2008, 06:01 AM

If there are more users with the same counter number would it be possible to check if logout =/= 0:00:00
or where the datum+uur is the biggest ?

samjudson · May 16th, 2008, 06:37 AM

I suggest you look at the SelectNodes method, rather than the SelectSingleNode. This will return a XmlNodeList which you can loop through and do your checking.

/- Sam Judson : Wrox Technical Editor -/