public void Insert(StockItem stockItem) { try { string q = "INSERT INTO STOCKITEM VALUES (@id, @name, @desc, @sNo, @qty, @price, @category);"; var cmd = new SqlCommand(q, conn); cmd.Parameters.AddWithValue("@id", stockItem.Id); cmd.Parameters.AddWithValue("@name", stockItem.Name); cmd.Parameters.AddWithValue("@desc", stockItem.Desc); cmd.Parameters.AddWithValue("@sNo", stockItem.Sno); cmd.Parameters.AddWithValue("@qty", stockItem.Qty); cmd.Parameters.AddWithValue("@price", stockItem.Price); cmd.Parameters.AddWithValue("@category", stockItem.Category); cmd.ExecuteNonQuery(); } catch { MessageBox.Show("Duplicate Primary Key. Please enter a different Id Number"); } }