Recursive procedures to check if a given node is the immediate parent or a child node of another node in an XML DOM tree

Introduction

This article explains two simple procedures to check if a given node is a child node or the immediate parent node of another node. An XML DOM tree consists of a number of XML nodes. If it is required to check if a node in an XML DOM tree is a child node or the immediate parent node in the same tree, use the simple procedures shown below. These are recursive procedures.

1. checkNode is of type XmlNode and used to check whether the node is a child node of parentNode of type XmlNode. Make sure that both are in the same XmlDocument. Otherwise, it always returns False.
VB

Public Function IsCheckNodeChildNodeOfParentNode(ByRef parentNode _
                As XmlNode, ByRef checkNode As XmlNode) As Boolean
    Try
        Dim xNode As XmlNode
        If checkNode Is parentNode Then
            Return True
        ElseIf parentNode.HasChildNodes Then
            For Each xNode In parentNode.ChildNodes
                If checkNode Is xNode Then
                    Return True
                Else
                    If IsCheckNodeChildNodeOfParentNode(xNode, _
                       checkNode) Then
                        Return True
                    End If
                End If
            Next
        Else
            Return False
        End If
        Return False
    Catch ex As Exception
    End Try
End Function

2. checkNode is of type XmlNode and is used to check whether the node is the immediate parent node of parentNode of type XmlNode. Make sure that both are in the same XmlDocument. Otherwise, it always returns False.
VB

Public Function IsCheckNodeImmediateParentNodeOfParentNode(ByRef childNode _
       As XmlNode, ByRef checkNode As XmlNode) As Boolean
    Try
        Dim parentNode As XmlNode = childNode.ParentNode
        If Not parentNode Is Nothing Then
            If Not parentNode.Name.ToLower.Trim = "#document" Then
                If checkNode Is parentNode Then
                    Return True
                Else
                    Return IsCheckNodeImmediateParentNodeOfParentNode(parentNode, _
                           checkNode)
                End If
            Else
                Return False
            End If
        End If
        Return False
    Catch ex As Exception
    End Try
End Function