private void ProductTree_NodeMouseDoubleClick(object sender, TreeNodeMouseClickEventArgs e)
        {
            Items itm = new Items();
            DataTable dtItem = new DataTable();
            string value = ProductTree.SelectedNode.Name;
            string type = value.Substring(0, 3);
            int len = value.Length - 3;
            int categoryId = Convert.ToInt32(value.Substring(3,len));
            if (type == "cat")
            {
                dtItem = itm.GetItemsByCategory(categoryId);
                lblState.Text = "All Items under " + ProductTree.SelectedNode.Text + " Category";

            }
            else if(type == "sub")
            {
                dtItem = itm.GetItemsBySubCategory(categoryId);
                lblState.Text = "All Items under " + ProductTree.SelectedNode.Text + " Sub Category";
                catID = categoryId;
            }
            else if (type == "sup")
            {
                dtItem = itm.GetSupplyByCategory(categoryId);
                lblState.Text = "All Items under " + ProductTree.SelectedNode.Text + " Category";
                catID = categoryId;
            }
            else if (type == "Als")
            {
                dtItem = itm.GetAllSupply();
                lblState.Text = "All Items under " + ProductTree.SelectedNode.Text + " Category";
                catID = categoryId;
            }
            else
            {
                dtItem = itm.GetAllItems(1);
                lblState.Text = "All Items";
            }
            PopulateItemList(dtItem);
        }
        /// <summary>
        /// Populates Item list based on the selected category in the treeCategory
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void treeCategory_FocusedNodeChanged(object sender, DevExpress.XtraTreeList.FocusedNodeChangedEventArgs e)
        {
            DataRowView dr = (DataRowView)treeCategory.GetDataRecordByNode(treeCategory.Selection[0]);
            Items itm = new Items();
            DataTable dtItem;
            //TODO: filter criteria;
            string value = dr["ID"].ToString();
            string type = value.Substring(0,1);
            _catId = 0;
            int categoryId = Convert.ToInt32(value.Substring(1));

            dtItem = itm.GetSupplyByCategory(categoryId);
            toolStripButtonAddItems.Enabled = true;
            _catId = categoryId;
            toolStripButtonEditItem.Enabled = false;
            _selectedSubCat = categoryId;
            PopulateItemList(dtItem);
        }