public Tree<ItemModel> GetItemModelTree()
{
var tree = new Tree<ItemModel>(GetItemModels());
var propModels = dataProvider.GetAllProperties().Select(p => p.ToPropertyModel());
var propValModels = dataProvider.GetAllPropertiyValues().Select(pv => pv.ToPropertyValueModel());
tree.FillNodePropertyValues(propModels.ToList(), propValModels);
return tree;
}