treeview grandfather,parent and son names

Question

I have tree view which has grandfather node and inside of this grandfather there is parent and inside this parent there is son node. How I can get the names of this grandfather , parent and son nodes. I already did the code to work when the user double clicks on the son node, but still I am unable to get the names for the grandfather, parent and child nodes. here is my code:

 Private Sub TreeView1_NodeMouseDoubleClick(sender As Object, e As TreeNodeMouseClickEventArgs) Handles TreeView1.NodeMouseDoubleClick

        Dim ClickPoint As Point = New Point(e.X, e.Y)
        Dim ClickedChildNode As TreeNode = TreeView1.GetNodeAt(ClickPoint)

        If ClickNode Is Nothing Then

            Exit Sub

        End If

                Dim strGrandFatherName As String
                Dim strParentName As String
                Dim strSonName As String

strGrandFatherName = ?
strParentName = ?
strSonName = ?

Thank you