Public Class SmartSiteMapProvider
    Inherits XmlSiteMapProvider

    Public Overrides Sub Initialize(ByVal name As String, ByVal attributes As NameValueCollection)

        MyBase.Initialize(name, attributes)
        Dim resolveHandler As New SiteMapResolveEventHandler(AddressOf SmartSiteMapProvider_SiteMapResolve)
        AddHandler Me.SiteMapResolve, resolveHandler

    End Sub

    Function SmartSiteMapProvider_SiteMapResolve(ByVal sender As Object, ByVal e As SiteMapResolveEventArgs) _
    As SiteMapNode

        If (SiteMap.CurrentNode Is Nothing) Then Return Nothing

        Dim this As New XmlSiteMapProvider

        Dim temp As SiteMapNode
        temp = SiteMap.CurrentNode.Clone(True)
        Dim u As Uri = New Uri(e.Context.Request.Url.ToString())

        Dim tempNode As SiteMapNode = temp
        While Not tempNode Is Nothing

            Dim qs As String = GetReliance(tempNode, e.Context)

            If Not qs Is Nothing Then

                If Not tempNode Is Nothing Then

                    tempNode.Url += qs

                End If

                tempNode = tempNode.ParentNode
            End If

        End While

        Return temp

    End Function

    Private Function GetReliance(ByVal node As SiteMapNode, ByVal context As HttpContext) As String

        'Check to see if the node supports reliance
        If node("reliantOn") Is Nothing Then Return Nothing

        Dim values As NameValueCollection = New NameValueCollection
        Dim vars() As String = node("reliantOn").Split(",".ToCharArray())

        Dim s As String
        For Each s In vars

            Dim var As String = s.Trim()
            'Make sure the var exists in the querystring
            If context.Request.QueryString(var) Is Nothing Then Continue For

            values.Add(s, context.Request.QueryString(var))

        Next

        If values.Count = 0 Then Return Nothing

        Return NameValueCollectionToString(values)

    End Function

    Private Function NameValueCollectionToString(ByVal col As NameValueCollection) As String

        Dim parts(col.Count) As String
        Dim keys() As String = col.AllKeys

        Dim i As Integer
        For i = 0 To keys.Length
            parts(i) = keys(i) + "=" + col(keys(i))
        Next

        Dim url As String = "?" + String.Join("&", parts)

        Return url

    End Function

End Class

public static SiteMapNode HandleUnmappedNodes(object sender, SiteMapResolveEventArgs e)
{
    HttpContext context = HttpContext.Current;
    SiteMapNode currentNode = SiteMap.CurrentNode.Clone(true);
    SiteMapNode tempNode = currentNode;

    // Change title for leaf nodes.
    if (context.Request.Path.ToLower().Contains("showarticle.aspx"))
    {
        string param = context.Request["QueryStringAppendage"];
        string title = String.IsNullOrEmpty(param) ?
            "Unmapped Page" : param;
        currentNode.Title = title;
        return currentNode;
    }

    return null; // Do nothing for other URLs.
}

string ordNum = Request.QueryString["OrderNum"];