private void button1_Click(object sender, EventArgs e) { if (string.IsNullOrWhiteSpace(pricetextbox.Text) || comboBox1.Text == "") { MessageBox.Show("Make sure to fill Type, supplier_name, Price"); return; } string p = pricetextbox.Text; double result; if (!Double.TryParse(p, out result)) { MessageBox.Show("Please enter a proper price"); return; } float price = (float)Convert.ToDouble(p); controllerObj.AddProduct(comboBox2.Text, price); string pid = Convert.ToString(controllerObj.GetProductID()); DataTable dt = controllerObj.SelectBranches(); for (int i = 0; i < dt.Rows.Count; i++) { string branch = dt.Rows[i][0].ToString(); controllerObj.InsertProductinBranchHas(pid, branch); controllerObj.InsertProductinBranchSold(pid, branch); } if (comboBox1.Text == "Motorcycle") { Motorcycle m = new Motorcycle(); m.Show(); } else if (comboBox1.Text == "Sparepart") { new SpareParts().Show(); } else if (comboBox1.Text == "Accessory") { new Accessories().Show(); } }