Solution - Challenge Conditional RadioButton

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

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This is the Solution for the Challenge titled ChallengeConditionalRadioButton. As always, read only as much as you need to solve the specific issue you're having, but try to solve the rest on your own. Struggling with concepts is part of learning, and overcoming these challenges will give you an advantage down the road in this course.

Step 1: Add the Server Controls

By now you should be familiar with creating a Project and your Default.aspx page, so create those as we have been in the lessons. Switch to the Design view in Visual Studio to begin adding Server Controls to your form. You'll need to style your form as shown below, with four RadioButtons, a Button and a Label:

InitialForm

Next, change the programmatic ID's of each of the Server Controls to the following:

  1. pencilRadioButton
  2. penRadioButton
  3. phoneRadioButton
  4. tabletRadioButton
  5. okButton
  6. resultLabel

Step 2: Working with the okButton_Click

Once all of this is set up as shown, double-click on the okButton to generate an EventHandler for when the okButton is clicked. Inside this code block, write if() and else if() statements to check which RadioButton is selected:

okButtonClick

Note: While you could create each individual if() and else if() statement in its entirety before creating the next, creating all of them at the same time will allow you to copy and paste the code for your conditional into the next.

Inside the first if() statement, set the resultLabel's Text property to "You selected Pencil". Copy and paste this code into each of the else if() statements:

IfElseIf

Now, simply change the word Pencil in the literal string to the appropriate RadioButton. i.e. Pen for penRadioButton. Finally, add an else() statement in the event that the user doesn't select a RadioButton at all. Inside the else(), set the resultLabel's Text to "Please select an option". Your code should look like this:

resultLabelFinal

Now, save and run your code to test the Project. You'll notice that the program runs as intended if you select a RadioButton, but it allows multiple RadioButtons to be selected at the same time.

MultipleSelections

Step 3: RadioButton Groups

To fix this, go back to the Default.aspx page and select the pencilRadioButton. In the Properties window, under Behavior, you will find the GroupName property. Set this property to NoteGroup for all the RadioButtons. This will force their selection to be mutually exclusive so that only one condition can be true at a time.

groupName

Save and run your Project again. This time, you will find that the resultLabel displays the appropriate value for the selection, and only one RadioButton can be selected at a time.

FinalGroup

Bonus: Image Control

This bonus challenge deals with a Server Control we have not discussed yet: Image. What you need to do is display one of four images provided in the code folder for this Challenge depending on what the user's selection was.

To begin with, open up the code folder for this lesson and drag the four images under the "Assets" section into your Project:

SolutionExplorer

Next, add a space underneath your okButton and insert the Image Server Control by double-clicking it. Change its programmatic ID to 'resultImage'. You'll also see in the Properties window for the Image, under Appearance, there is a property called ImageUrl:

ImageUrl

While the Properties window allows you to manually set the ImageUrl, this Challenge requires you to change it at runtime. In order to do this, go back into the okButton_Click Event. Copy and paste the if() and else if() statements, then comment out the originals. Clear out the resultLabel code in each of the if() and else if() statements you just pasted, with the exception of the else():

CopyPaste

In the if() statement for the pencilRadioButton, add a line that says, 'resultImage.ImageUrl = "pencil.png" ' Note the quotation marks around "pencil.png", this is necessary in order to reference the file you added to your Project. Repeat this step for each of the else if() statements, selecting the appropriate ImageUrl for each:

finalIf

Save and run your Project to see the result:

Phone

Conclusion

Congratulations on completing the ChallengeConditionalRadioButton! If you had trouble, I encourage you to revisit this Challenge and try again. Keep trying until this becomes second nature to you, as repetition will reinforce what you are learning. You're doing a great job so far, keep it up!


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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