private void btnAdd_Click(object sender, EventArgs e) { //Check if textboxes are empty foreach (var item in AddProductTab.Controls) { if (item.GetType() == typeof(TextBox)) { if (string.IsNullOrEmpty(((TextBox)item).Text)) { MessageBox.Show("All fileds must be filled"); return; } } } //Create product object Product product = new Product(); product.id = int.Parse(tBoxAddID.Text); product.name = tBoxName.Text; product.dateOfArival = dtpDateOfArival.Value; product.dateOfShipment = checkBoxShipmentEmpty.Checked ? DateTime.MinValue : dtpDateOfShipment.Value; product.purchasePrice = double.Parse(tBoxPurchasePrice.Text); product.sellingPrice = double.Parse(tBoxSellPrice.Text); product.numberAvalible = double.Parse(tBoxAmount.Text); product.weight = double.Parse(tBoxWeight.Text); product.description = rtbDescription.Text; product.size.x = double.Parse(tBoxAddSizeX.Text); product.size.y = double.Parse(tBoxAddSizeY.Text); product.size.z = double.Parse(tBoxAddSizeZ.Text); product.barcode = tBoxBarcode.Text; try { //Add it do products list ProductsHolder.products.Add(product); Debug.WriteLine("Adding product from product form"); ProductClient.InsertProduct(product); //Set new ID tBoxAddID.Text = (ProductsHolder.products.Count == 0 ? 0 : (from elem in ProductsHolder.products select elem.id).Max() + 1).ToString(); } catch (Exception) { MessageBox.Show("Failed to insert product"); } }