Papa Bob's Mega Solution Part 6 - Creating an Order with Validation

Tutorial Series: Free C# Fundamentals via ASP.NET Web Apps

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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.

Step 1: Determining the Pizza Size

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:


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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:


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If the TryParse() is unsuccessful, we're going to throw an exception, saying that the crust could not be determined:


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Then, return to orderButton_Click and set orderDTO.Size to the returned value of determineSize():


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Step 2: Determining Crust and Toppings

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:


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Then, copy and paste in the conditional check from determineSize(), but modify it for the crust:


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Then, just like Size, set the Crust property of the orderDTO to the value of determineCrust():


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The toppings will be determined simply by returning the value of their Checked property:


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Step 3: Creating a Custom Error Message for TextBoxes

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:


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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():


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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:


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Step 4: Validating the TextBox Data

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:


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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:


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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:


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Create checks for the rest of the TextBoxes following the same pattern, then close out the method with an else statement that returns true:


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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:


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Step 5: Finalizing the Order Submission

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:


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Then, return to Default.aspx.cs and create a new method called determinePayment():


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Inside this method, create a conditional check to determine which RadioButton the user selected, and set paymentMethod to the corresponding enum:


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Then, set the orderDTO's PaymentType to the value returned from this method:


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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'.

Step 6: Testing the Order Process

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:


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Now, save and run the application to test its functionality:

Error:


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Successful Order:


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Database Entry:

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Conclusion:

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.


Related Articles in this Tutorial:

Lesson 1 - Series Introduction

Lesson 2 - Installing Visual Studio 2015

Lesson 3 - Building Your First Web App

Lesson 4 - Understanding What You Just Did

Lesson 5 - Working with Projects in Visual Studio

Lesson 6 - Simple Web Page Formatting in Visual Studio

Challenge 1

Solution 1

Lesson 7 - Variables and Data Types

Lesson 8 - Data Type Conversion

Lesson 9 - Arithmetic Operators

Lesson 10 - C# Syntax Basics

Challenge 2 - ChallengeSimpleCalculator

Solution - ChallengeSimpleCalculator

Lesson 11 - Conditional If Statements

Lesson 12 - The Conditional Ternary Operator

Challenge 3 - ChallengeConditionalRadioButton

Solution - Challenge Conditional RadioButton

Lesson 13 - Comparison and Logical Operators

Lesson 13 Challenge - First Papa Bob's Website

Solution - Challenge First Papa Bob's Website

Lesson 14 - Working with Dates and Times

Lesson 15 - Working With Spans of Time

Lesson 16 - Working with the Calendar Server Control

Challenge 4 - Challenge Days Between Dates

Solution - Challenge Days Between Dates

Lesson 17 - Page_Load and Page.IsPostBack

Lesson 18 - Setting a Break Point and Debugging

Lesson 19 - Formatting Strings

Challenge 5 - Challenge Epic Spies Assignment

Solution - Challenge Epic Spies Assignment

Lesson 20 - Maintaining State with ViewState

Lesson 21 - Storing Values in Arrays

Lesson 22 - Understanding Multidimensional Arrays

Lesson 23 - Changing the Length of an Array

Challenge 6 - Challenge Epic Spies Asset Tracker

Solution - Challenge Epic Spies Asset Tracker

Lesson 24 - Understanding Variable Scope

Lesson 25 - Code Blocks and Nested If Statements

Lesson 26 - Looping with the For Iteration Statement

Challenge 7 - Challenge For Xmen Battle Count

Solution - Challenge For Xmen Battle Count

Lesson 27 - Looping with the while() & do...while() Iteration Statements

Lesson 28 - Creating and Calling Simple Helper Methods

Lesson 29 - Creating Methods with Input Parameters

Lesson 30 - Returning Values from Methods

Lesson 31 - Creating Overloaded Methods

Lesson 32 - Creating Optional Parameters

Lesson 33 - Creating Names Parameters

Lesson 34 - Creating Methods with Output Parameters

Challenge 8 - Challenge Postal Calculator Helper Methods

Solution - Challenge Postal Calculator Helper Methods

Mega Challenge Casino

Solution - Mega Challenge Casino

Lesson 35 - Manipulating Strings

Challenge 9 - Phun With Strings

Solution - Challenge Phun With Strings

Lesson 36 - Introduction to Classes and Objects

Challenge - Hero Monster Classes Part 1

Solution - Hero Monster Classes Part 1

Challenge - Hero Monster Classes Part 2

Solution - Challenge Hero Monster Classes Part 2

Lesson 37 - Creating Class Files Creating Cohesive Classes and Code Navigation

Lesson 38 - Understanding Object References and Object Lifetime

Lesson 39 - Understanding the .NET Framework and Compilation

Lesson 40 - Namespaces and Using Directives

Lesson 41 - Creating Class Libraries and Adding References to Assemblies

Lesson 42 - Accessibility Modifiers, Fields and Properties

Lesson 43 - Creating Constructor Methods

Lesson 44 - Naming Conventions for Identifiers

Lesson 45 - Static vs Instance Members

Challenge 10 - Challenge Simple Darts

Solution - Challenge Simple Darts

Lesson 46 - Working with the List Collection

Lesson 47 - Object Initializers

Lesson 48 - Collection Initializers

Lesson 49 - Working with the Dictionary Collection

Lesson 50 - Looping with the foreach Iteration Statement

Lesson 51 - Implicitly-Typed Variables with the var Keyword

Challenge 11 - Challenge Student Courses

Solution - Challenge Student Courses

Mega Challenge War

Solution - Mega Challenge War

Lesson 52 - Creating GUIDs

Lesson 53 - Working with Enumerations

Lesson 54 - Understanding the switch() Statement

Lesson 55 - First Pass at the Separation of Concerns Principle

Lesson 56 - Understanding Exception Handling

Lesson 57 - Understanding Global Exception Handling

Lesson 58 - Understanding Custom Exceptions

Lesson 59 - Creating a Database in Visual Studio

Lesson 60 - Creating an Entity Data Model

Lesson 61 - Displaying the DbSet Result in an ASP.NET GridView

Lesson 62 - Implementing a Button Command in a GridView

Lesson 63 - Using a Tools-Centric Approach to Building a Database Application

Lesson 64 - Using a Maintenance-Driven Approach to Building a Database Application

Lesson 65 - Creating a New Instance of an Entity and Persisting it to the Database

Lesson 66 - Package Management with NuGet

Lesson 67 - NuGet No-Commit Workflow

Lesson 68 - Introduction the Twitter Bootstrap CSS Framework

Lesson 69 - Mapping Enum Types to Entity Properties in the Framework Designer

Lesson 70 - Deploying the App to Microsoft Azure Web Services Web Apps

Papa Bob's Mega Challenge

Papa Bob's Mega Solution Part 1 - Setting up the Solution

Papa Bob's Mega Solution Part 2 - Adding an Order to the Database

Papa Bob's Mega Solution Part 3 - Passing an Order from the Presentation Layer

Papa Bob's Mega Solution Part 4 - Creating the Order Form

Papa Bob's Mega Solution Part 5 - Adding Enums

Papa Bob's Mega Solution Part 6 - Creating an Order with Validation

Papa Bob's Mega Solution Part 7 - Calculating the Order Price

Papa Bob's Mega Solution Part 8 - Displaying the Price to the User

Papa Bob's Mega Solution Part 9 - Creating the Order Management Page


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