static public Category xml2Category(XmlNode xml)
        {
            Category info = new Category();
            info.name = xml.SelectSingleNode("Name").InnerText;
            info.id = int.Parse(xml.Attributes.GetNamedItem("ID").InnerText);
            info.ownerId = int.Parse(xml.SelectSingleNode("OwnerId").InnerText);

            return info;
        }
        private void updateCategoriesListBox()
        {
            Program.allCategories = Program.fetcher.getCategories();
            
            Category noneCat = new Category();
            noneCat.name = "None";
            noneCat.id = 0;
            noneCat.ownerId = 0;

            listViewCategories.Clear();
            comboBoxCategory.Items.Clear();
            comboBoxCategory.Items.Add(noneCat);
            comboBoxCategory.SelectedItem = noneCat;

            foreach( Category cat in Program.allCategories.Values )
            {
                ListViewItem item = new ListViewItem(cat.name);
                item.Tag = cat.id.ToString();

                if (!Program.isSuperAdmin && (cat.ownerId != Program.UserId))
                {
                    item.ForeColor = Color.LightGray;
                }

                listViewCategories.Items.Add(item);

                comboBoxCategory.Items.Add(cat);
            }
        }