public void exportToXml(TreeView tv, string filename)
        {
            xr = new XmlTextWriter(filename, System.Text.Encoding.UTF8);
            
            xr.Formatting = Formatting.Indented;
            xr.WriteStartDocument();

       if (man.p_xmlns == null || man.p_xmlns_imsmd == null || man.p_xmlns_xsi == null || man.p_xmlns_adlcp == null || man.p_xsi_schemaLocation == null)
            {
                MessageBox.Show("Manifest Form Error", "Please Compile Every Field", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                manform = new  ManifestForm(man);
                man.FormMan = manform;
                man.FormMan.Show();
                
            }
            else
            {
                xr.WriteStartElement(treeView2.Nodes[0].Text);
                xr.WriteStartAttribute("xmlns");
                xr.WriteValue(man.p_xmlns);
                xr.WriteEndAttribute();
                xr.WriteStartAttribute("xmlns:imsmd");
                xr.WriteValue(man.p_xmlns_imsmd);
                xr.WriteEndAttribute();
                xr.WriteStartAttribute("xmlns:xsi");
                xr.WriteValue(man.p_xmlns_xsi);
                xr.WriteEndAttribute();
                xr.WriteStartAttribute("xmlns:adlcp");
                xr.WriteValue(man.p_xmlns_adlcp);
                xr.WriteEndAttribute();
                xr.WriteStartAttribute("xmlns:schemalocation");
                xr.WriteValue(man.p_xsi_schemaLocation);
                xr.WriteEndAttribute();
            }

            foreach (TreeNode node in tv.Nodes)
            {
                saveNode(node.Nodes);
            }

            xr.WriteEndElement();
            xr.Close();
        }

        private void saveNode(TreeNodeCollection tnc) 
        {
            foreach (TreeNode node in tnc)
            {
    if (node.Tag == "organization") -> puo essere una soltanto...non ho problemi
                    {
                      
                            xr.WriteStartElement(node.Text);
                            xr.WriteStartAttribute("id_organization");
                            xr.WriteValue(org.p_id_organization);
                            xr.WriteEndAttribute();
                            xr.WriteStartAttribute("channel_type");
                            xr.WriteValue(org.p_channel_organization);
                            xr.WriteEndAttribute();
                            xr.WriteStartAttribute("struct_organization");
                            xr.WriteValue("hierarchical");
                            xr.WriteEndAttribute();
                            xr.WriteElementString("title", org.p_title_organization);
                            saveNode(node.Nodes);
                            xr.WriteEndElement();

                        
                    }
                   
                    else if (node.Text == "item") -> qui ho problemi dato che gli item possono essere n e quando vado a salvare il file xml in tutti gli item ottengo gli stessi valori(tutti hanno i valori dell ultimo item editato) 
                    {
                        xr.WriteStartElement(node.Text);
                        xr.WriteStartAttribute("id_item");
                        xr.WriteValue(item.p_id_item);
                        xr.WriteEndAttribute();
                        xr.WriteStartAttribute("ref_element");
                        xr.WriteValue(item.p_refelem_item);
                        xr.WriteEndAttribute();
                        xr.WriteElementString("title", item.p_title_item);
                        saveNode(node.Nodes);
                        xr.WriteEndElement();
                    }

                   
                    
                }