CountCheckedNodes - Retrieving the number of checked nodes in a treeview

' Return the number of checked nodes in the specified tree
Public Function CountCheckedNodes(ByVal rootNode As TreeNode) As Integer
    Dim count As Integer = 0
    ' count the root node, if checked
    If rootNode.Checked Then count = 1
    ' check the child nodes, by recursively calling this function for all of 
    ' them
    Dim tvn As TreeNode
    For Each tvn In rootNode.Nodes
        count += CountCheckedNodes(tvn)
    Next
    Return count
End Function