Search XML to Grab Info

I created the following procedure a while ago, and decided to share it, because I’m fairly proud of it. I wrote it to grab the user’s default font settings from the SAP configuration file, but I think it could be used to parse virtually any XML file and extract just the information that we need from it.

	”’ <summary>
	”’ Searches within an XML file, through specific elements, for a specific attribute that has a specific value.
	”’ If we find the attribute that has a specific value that we desire, then we return the text value of that node
	”’ </summary>
	”’ <param name=”sInputFile”>Input file name</param>
	”’ <param name=”sElementsToSearch”>String of the element tags that we want to search through</param>
	”’ <param name=”sAttributeToSearchFor”>String of the name of the attribute that the element must contain</param>
	”’ <param name=”sAttrValToSearchFor”>String of the value of the attribute that the element must contain</param>
	”’ <returns>Returns the sought after value on success, Nothing on failure</returns>
	”’ <remarks></remarks>
	Private Function searchXMLFile(ByVal sInputFile As String, ByVal sElementsToSearch As String, ByVal sAttributeToSearchFor As String, ByVal sAttrValToSearchFor As String) As String
	Try
	Dim xmlReader As XmlTextReader = New XmlTextReader(sInputFile)
	Dim blnFoundAttribute As Boolean = False

	‘Continue while there’s something to read
	Do While (xmlReader.Read())

	‘Determine what aspect of a node this is
	Select Case xmlReader.NodeType

	Case XmlNodeType.Element
	‘The beginning tag of an element

	‘Skip the element if it’s not one of the elements that we want to search in
	If xmlReader.Name.IndexOf(sElementsToSearch) = -1 Then
	Continue Do
	End If

If xmlReader.HasAttributes Then ‘If attributes exist

	‘Enumerate through all of the attributes, one by one until we find the desired attribute
	While xmlReader.MoveToNextAttribute() AndAlso Not blnFoundAttribute

	‘This queries the “name” of the attribute
	If xmlReader.Name.IndexOf(sAttributeToSearchFor) = -1 Then
	Continue While
	Else
	‘Check the “value” of the attribute and ensure that it matches what we’re looking for
	If xmlReader.Value.IndexOf(sAttrValToSearchFor) = -1 Then
	Continue While
	Else
	blnFoundAttribute = True
	Exit While
	End If
	End If
	End While
	End If
	Case XmlNodeType.Text
	‘The text value within an element

	‘If we found the attribute that we were searching for, then this value must be the value that we want to return
	If blnFoundAttribute Then
	Return xmlReader.Value
	End If

	Case XmlNodeType.EndElement ‘Display the end of the element
	‘The end tag of the element
	End Select
	Loop

	‘If we got here, then we didn’t find what we are looking for, return nothing
	Return Nothing

	Catch ex As Exception
	MsgBox(“Error in procedure ” & System.Reflection.MethodInfo.GetCurrentMethod.Name.ToString & “: ” & ex.Message.ToString)
	Return Nothing
	End Try
	End Function