static void Main(string[] args)
        {
            string          connectionString = ConfigurationManager.ConnectionStrings["Shop"].ConnectionString;
            CategoryStorage cs = new CategoryStorage();

            cs.Connection = new System.Data.SqlClient.SqlConnection(connectionString);
            //var collection = cs.GetCategory();
            //var colllection_ = collection;

            //foreach (var item in collection)
            //{
            //    Console.WriteLine(item.CategoryName);
            //}
            cs.Add(new _Category {
                CategoryName = "Test1"
            });
            cs.Add(new _Category {
                CategoryName = "Test2"
            });
            cs.Add(new _Category {
                CategoryName = "Test3"
            });
            cs.Add(new _Category {
                CategoryName = "Test4"
            });
            //cs.Del(5);
            //cs.Del(8);
        }
        private void FormAddBtn(object sender, EventArgs e)
        {
            string          connectionString = ConfigurationManager.ConnectionStrings["Shop"].ConnectionString;
            CategoryStorage cs = new CategoryStorage();

            cs.Connection = new System.Data.SqlClient.SqlConnection(connectionString);
            var c = cs.Add(new _Category {
                CategoryName = Form.tbCatName.Text
            });

            GetData();
            Form.dGW1.Refresh();
        }