Getting rid of duplication in a VB list box - asp.net

Question

Using ASP/VB, I'm trying to get rid of some duplication in a list box that is coming from an XML document.
Sorry if this is a daft question, I'm new to this.
I've tried various things, but nothing has worked. Here is the code - thanks for any help / assistance!
Function getAssets(ByVal siteid As String) As String
Dim oAssets As New Xteam.XteamWebService
Dim strAssets As String = ""
Dim oDoc As New XmlDocument
'Dim oNode As XmlNode
strAssets = oAssets.ReadHAssetCodes(siteid)
oDoc.LoadXml(strAssets)
For Each Node As XmlNode In oDoc.SelectSingleNode("XteamAssets")
lstHAssets.Items.Add(New ListItem(Node("hassetdescription").InnerText, Node("hassetcode").InnerText))
Next
lstHAssets.Items.Insert(0, "--Please Select--")
Return "ToSender"
End Function

Answer 1

There's probably a more efficient way but this will work.
Function getAssets(ByVal siteid As String) As String
Dim oAssets As New Xteam.XteamWebService
Dim strAssets As String = ""
Dim oDoc As New XmlDocument '
Dim oNode As XmlNode
strAssets = oAssets.ReadHAssetCodes(siteid)
oDoc.LoadXml(strAssets)
Dim strAryUniqueValues as string()
Dim strUniqueValues as string = ""
Dim i as int = 0
Dim strSearchPair as string
For Each Node As XmlNode In oDoc.SelectSingleNode("XteamAssets")
strSearchPair = "~" & Node("hassetdescription").InnerText & "/" & Node("hassetcode").InnerText & "~"
' see if these values have been included already, if not then add them
if instr(strUniqueValues,strSearchPair) = -1 then
strAryUniqueValues(i) = strSearchPair
strUniqueValues = strUniqueValues & strAryUniqueValues(i)
i = i + 1
end if
Next
'now loop back through and build your listbox
Dim strAryPair as string()
For each strPair in strAryUniqueValues
strAryPair = split(strPair,"/")
lstHAssets.Items.Add(New ListItem(Replace(strAryPair(0),"~",""),Replace(strAryPair(1),"~",""))
Next
lstHAssets.Items.Insert(0, "--Please Select--")
Return "ToSender"
End Function