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XML/Combobox VB.net Problems

I am trying to have XML data show results in a combobox (Which works) and
when the combobox has a selection, change the text in a label field.

I am following the video from
http://msdn.microsoft.com/vbasic/att...l/default.aspx (reading
XML data) almost step by step (changing to match my xmlfiles, etc)

Here is an example of my XML
<products>
<product>CP-90, T-32</product>
<company>Carwel l</company>
<address>Stre et Address</address>
<city>City</city>
<state>State</state>
<zip>Zip</zip>
</products>

My load function (which works)

Dim xmlFile As String = "..\Products.xm l"
Dim xmlDoc As XmlDocument
Private Sub Zadig_Load(ByVa l sender As System.Object, ByVal e As
System.EventArg s) Handles MyBase.Load
Dim xmlTr As New XmlTextReader(x mlFile)

While xmlTr.Read
If xmlTr.Name = "product" AndAlso xmlTr.NodeType =
XmlNodeType.Ele ment Then
cmbProducts.Ite ms.Add(xmlTr.Re adString)
End If
End While
xmlTr.Close()

xmlDoc = New XmlDocument
xmlDoc.Load(xml File)

End Sub

My selection method
Private Sub cmbProducts_Sel ectionChangeCom mitted(ByVal sender As Object,
ByVal e As System.EventArg s) Handles cmbProducts.Sel ectionChangeCom mitted
DisplayProduct( cmbProducts.Sel ectedIndex + 1)
End Sub

Here is where the problem begins

Sub DisplayProduct( ByVal position As Integer)
Dim node As XmlNode = xmlDoc.SelectSi ngleNode( _
"/products/product[" & position & "]")
lblCompany.Text = node.SelectSing leNode("company ").InnerTex t

End Sub

Everything compiles fine but when I run and then select a product I get.
An unhandled exception of type 'System.NullRef erenceException ' occurred in
Zadig.exe

Additional information: Object reference not set to an instance of an object.

The error says it is on line "lblCompany.Tex t =
node.SelectSing leNode("company ").InnerTex t" but I have no idea what the real
problem is.

Please advise.

Michael

Jul 21 '05 #1
0 1400

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