/// <summary>
        /// Private method that will load all our invoice IDs initially when a user opens the search invoice window
        /// </summary>
        private void loadInvoiceIDsInComboBox()
        {
            try
            {
                //call our method in our clsSearchSQL file that gets all the dates in the database
                invoiceIDArray = db.getInvoiceIDs();

                //iterate through the list that the clsSearchSQL file populated
                foreach (Invoice invoice in invoiceIDArray)
                {
                    //and put them in our combobox
                    InvoiceNumberDropDown.Items.Add(invoice);
                }
            }
            catch (Exception ex)
            {
                throw new Exception(MethodInfo.GetCurrentMethod().DeclaringType.Name + "." + MethodInfo.GetCurrentMethod().Name + " -> " + ex.Message);
            }
        }