This is the sixth part of the solution for Papa Bob's Mega Challenge. In this part, we're going to edit the orderButton_Click to pass through the information that the user input, as well as provide basic validation for the order.
Our ultimate goal in this part is to create a way for the Presentation layer to pass a content-verified user-submitted order to the Persistence layer. To do this, we'll need to create several methods that check to ensure that each property does in fact contain the necessary information and, if not, either throws an exception, or provides an error message to the user. This way, no incorrect data will make its way to the database or cause a breakdown.
To begin, delete the code populating the orderDTO's properties as we'll be rewriting this. Then, create a new method within Default.aspx.cs called determineSize() that returns a SizeType to the caller:
Inside of this method, we're going to use a TryParse() method specific to the Enum class to determine whether or not the value of the current DropDown selection of the sizeDropDown is valid or not:
If the TryParse() is unsuccessful, we're going to throw an exception, saying that the crust could not be determined:
Then, return to orderButton_Click and set orderDTO.Size to the returned value of determineSize():
We'll reuse much of the validation code of determineSize() for the crust validation. Create a new method called determineCrust() with a CrustType return value:
Then, copy and paste in the conditional check from determineSize(), but modify it for the crust:
Then, just like Size, set the Crust property of the orderDTO to the value of determineCrust():
The toppings will be determined simply by returning the value of their Checked property:
The other case we need to create validation for is the TextBox values input by the user. If any of the TextBoxes are left empty, we need to provide the user, not with an exception, but with an error message describing what they need to fix to submit their order. We'll need to create a new label for this purpose inside the Default.aspx page.
Just under the orderButton, create a new ASP Label control called validationLabel, and give it the following properties:
By default, this label will not be visible to the user. This ensures that no error message will display when the application runs successfully. The CssClass 'bg-danger' simply sets a red background color to the text that will display on the Label.
Because most of these cases will return the same basic message, ("Please enter a name" or, "Please enter a phone number") we can create a method in Default.aspx.cs that will be called to create the error message for all these cases. Create a new private method called textBoxValidationError():
This method will take in a string from the caller that will be used in the error message to tell which TextBox was invalid. Then, it sets the validationLabel's text to the error message and makes it visible:
At the top of the orderButton_Click, we'll need to ensure that the user input a value into all of the TextBoxes. While we could perform the conditional checks here, it would unnecessarily clutter the method. Instead, create the following conditional check on a new method:
The purpose of this method will be to perform the checks in the place of the Click event code block. If it returns false (the data is not valid) the flow of code will exit the Click event so as to prevent the order from being created. Highlight the 'textBoxDataIsValid' text and press 'Ctrl + .' to generate a method stub:
To begin, create a conditional check to see if the nameTextBox is left empty by the user. If this evaluates true, call the textBoxValidationError() method and return false to the caller:
Create checks for the rest of the TextBoxes following the same pattern, then close out the method with an else statement that returns true:
These checks will ensure that the order will not be created unless every user-reliant property is filled in properly. Because the information is already validated, we can simply set the name, address, phone and zipcode properties to the text value of the corresponding TextBox in the orderButton_Click:
The last steps are to ensure that the PaymentType is selected and pass that selection to the orderDTO. To avoid the need for a validation, go to Default.aspx and make the cash RadioButton selected by default:
Then, return to Default.aspx.cs and create a new method called determinePayment():
Inside this method, create a conditional check to determine which RadioButton the user selected, and set paymentMethod to the corresponding enum:
Then, set the orderDTO's PaymentType to the value returned from this method:
In the next part of the solution, we're going to calculate the total cost of the order, but for now, we'll just pass in the same hard-coded value of '16.50M'.
Before we can run the application, there's one last property that needs to be set, and that's the OrderId. However, because the responsibilities of the application are spread out between multiple layers, the place at which this property will be set is going to be different. In the Presentation layer, the user-determined properties are set. However, OrderId is not determined by the user, but by the system. Because of this, we'll set that property in the OrderManager:
Now, save and run the application to test its functionality:
This completes this large portion of the solution for Papa Bob's Mega Challenge. We now have all the data gathered that we need to successfully create and validate an order. In the next part of the solution, we'll begin calculating the total cost of the order.
Papa Bob's Mega Solution Part 6 - Creating an Order with Validation