Re: [DOTNET] What is best way to search XML document?

[Majercak Ivan]

I would say Xpath, here the code snippet I use quite often (partially from
MSDN :-):

Public Function GetValueFromXML(ByVal strXMLSrc As String, ByVal strXPath As
String)
        Dim strReturnValue As String
        Dim xpcContext As XmlParserContext
        Dim xtrReader As XmlTextReader
        Dim xpdDoc As XPathDocument
        Dim xpnNavigator As XPathNavigator
        Dim xpniInterator As XPathNodeIterator
        Dim xpeExpression As XPathExpression
        Dim intLoopCount As Integer = 0
        Dim dblReturnValue As Double

        Try
            xpcContext = New XmlParserContext(Nothing, Nothing, Nothing,
XmlSpace.None)
            xtrReader = New XmlTextReader(strXMLSrc, XmlNodeType.Document,
xpcContext)
            xpdDoc = New XPathDocument(xtrReader)
            xpnNavigator = xpdDoc.CreateNavigator()
            xpeExpression = xpnNavigator.Compile(strXPath)

            Select Case xpeExpression.ReturnType
                Case XPathResultType.Number
                    dblReturnValue = xpnNavigator.Evaluate(xpeExpression)
                    If Not Double.IsNaN(dblReturnValue) Then
                        strReturnValue = CStr(dblReturnValue)
                    End If

                Case XPathResultType.NodeSet
                    xpniInterator = xpnNavigator.Select(xpeExpression)
                    While xpniInterator.MoveNext()
                        If intLoopCount > 0 Then
                            strReturnValue = strReturnValue &
strValueSeparator
                        End If
                        strReturnValue = strReturnValue &
xpniInterator.Current.Value.ToString
                        intLoopCount = intLoopCount + 1
                    End While
                Case XPathResultType.Boolean
                    strReturnValue = xpnNavigator.Evaluate(xpeExpression)
                Case XPathResultType.String
                    strReturnValue = xpnNavigator.Evaluate(xpeExpression)
                Case Else
                    Throw New Exception("Invalid XpathResultType")
            End Select
            GetValueFromXML = strReturnValue
        Catch exException As Exception
            GetValueFromXML = ""
        End Try
    End Function

-----Original Message-----
From: Farhan [mailto:[EMAIL PROTECTED]]
Sent: Monday, June 03, 2002 1:58 PM
To: [EMAIL PROTECTED]
Subject: [DOTNET] What is best way to search XML document?


I want to query XML document, what is a best way to do that?

1. Data Island?
2. XPath?
3. XQuery?

I am new to all those terms so am not sure where to begin.

Thanks,
Farhan

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