public static void FillProductsComboBox(InvoiceForm f)
        {
            DataTable medecines;

            try
            {
                if (f.comboBox1.SelectedValue == null)
                {
                    MessageBox.Show("please select a Supplier");
                }
                else
                {
                    object[,] Params = new object[2, 1];
                    Params[0, 0]     = "@S_ID";
                    Params[1, 0]     = f.comboBox1.SelectedValue;
                    medecines        = dt.GetData_StoredProcedure("GetMedecinesINDVBySupplier", Params, "medecines");
                    medecines.Columns.Add("Info");
                    foreach (DataRow item in medecines.Rows)
                    {
                        item["Info"] = item["Name"].ToString() + "  -  " + item["Dosage"].ToString() + "  -  " + item["Volume"].ToString();
                    }
                    Filling.FillComboBox(f.myComboBox11, medecines, "ID", "Info");
                }
            }
            catch { MessageBox.Show("ERROR!!"); }
        }
        public static void FillSupplierComboBox(InvoiceForm f)
        {
            DataTable suppliers;

            suppliers = dt.GetData_StoredProcedure("GetSuppliersNames", "suppliers");
            Filling.FillComboBox(f.comboBox1, suppliers, "ID", "Supplier");
        }