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));
     switch (type)
     {
         case "C":
             dtItem = itm.GetItemsByCategory(categoryId);
             toolStripButtonAddItems.Enabled = false;
             toolStripButtonEditItem.Enabled = false;
             _selectedCat = categoryId;
             break;
         case "S":
             dtItem = itm.GetItemsBySubCategory(categoryId);
             toolStripButtonAddItems.Enabled = true;
             _catId = categoryId;
             toolStripButtonEditItem.Enabled = false;
             _selectedSubCat = categoryId;
             break;
         default:
             dtItem = itm.GetAllItem();
             toolStripButtonAddItems.Enabled = false;
             toolStripButtonEditItem.Enabled = false;
             _selectedCat = 0;
             break;
     }
     PopulateItemList(dtItem);
 }