How to display contextmenu only for certain nodes when right clicked in WinForms TreeViewAdv?

private void contextMenu1_Popup(object sender, System.EventArgs e)
{
   this.rightMouseDownNodeCached=this.treeViewAdv1.RMouseDownNode;
   // This will be null if the user clicked in the empty portion of the tree.
   this.treeViewAdv1.SelectedNode= this.treeViewAdv1.RMouseDownNode;
   if(this.treeViewAdv1.RMouseDownNode == null)
   {
      this.menuItem1.Visible = false;
   }
   else
   {
      if(treeViewAdv1.SelectedNode.Text=="Node0" ||treeViewAdv1.SelectedNode.Text=="Node2"|| treeViewAdv1.SelectedNode.Text=="Node4"||treeViewAdv1.SelectedNode.Text=="Node6")
      {
         this.menuItem1.Visible = true;
      }
      else
      {
         this.menuItem1.Visible = false;
      }
   }
}

Private Sub contextMenu1_Popup(ByVal sender As Object, ByVal e As System.EventArgs)
Me.rightMouseDownNodeCached=Me.treeViewAdv1.RMouseDownNode
   ' This will be null if the user clicked in the empty portion of the tree.
   Me.treeViewAdv1.SelectedNode= Me.treeViewAdv1.RMouseDownNode
   If Me.treeViewAdv1.RMouseDownNode Is Nothing Then
      Me.menuItem1.Visible = False
   Else
       If treeViewAdv1.SelectedNode.Text="Node0" OrElse treeViewAdv1.SelectedNode.Text="Node2" OrElse treeViewAdv1.SelectedNode.Text="Node4" OrElse treeViewAdv1.SelectedNode.Text="Node6" Then
         Me.menuItem1.Visible = True
       Else
         Me.menuItem1.Visible = False
       End If
   End If
End Sub