0.4 First Day Assignment

1. Back Up and Open Your Existing First Day Solution

Your First Day solution was renamed to your last name in 0.2. Keep that working name for the rest of the sequence. At the beginning of each module, make a backup of the completed previous checkpoint, then continue working in the original student-named solution.

Step 1 — Make a checkpoint backup

1. Close Visual Studio if the solution is open.
2. Locate the working parent folder named with your last name.
3. Make a backup copy and label it First Day 0.3 Backup LastName.
4. Leave the working folder name and LastName.sln unchanged.
5. Open LastName.sln from the working folder.

Step 2 — Verify the previous checkpoint

1. Build or run the solution before making the new 0.4 changes
2. Verify the major behavior you completed in 0.3 is still present
3. If the previous checkpoint is not working, correct that starting state before adding the new module work

2. Read the First Day Class Diagram

Module 0.2 used object diagrams to represent particular objects and their values. Module 0.3 used activity diagrams to represent what happens next. A class diagram answers a different question: What information can this kind of object hold, and how are the types related?

Step 1 — Compare classes and data types

The class diagram below summarizes several classes already present in your First Day project. Scalar information appears inside the class with its data type. Relationships to other classes are shown as labeled arrows.

Step 2 — Find examples of different data types

1. Find one string attribute
2. Find one int attribute
3. Find one double attribute
4. Find one bool attribute
5. Find one decimal attribute

Check Your Work

You should be able to explain why IsHungry : bool represents a true/false kind of value while FirstName : string represents text. You do not need to change these classes in this assignment.

3. Add the Shopping-List Controls

The next part of the application needs a place where you can enter several lines of text and a button that saves that text. The new controls are supplied so the focus stays on the information, not on designing the interface.

Step 1 — Open MainWindow.xaml

1. Open FirstDayScenario/MainWindow.xaml
2. Keep the existing 0.3 StackPanel and controls unchanged
3. Locate the space between the first StackPanel and the existing textOutput TextBox

Step 2 — Make room for the shopping-list section

Increase the Window height.

<Window x:Class="FirstDayScenario.MainWindow" ... Title="MainWindow" Height="720" Width="400">

Step 3 — Add the supplied shopping-list controls

Place this new StackPanel after the existing 0.3 StackPanel and before textOutput.

<StackPanel HorizontalAlignment="Center" Height="245" Margin="0,215,0,0" VerticalAlignment="Top" Width="300">
    <TextBlock Text="School Shopping List" FontWeight="Bold" Margin="5" />
    <TextBox x:Name="shoppingListTextBox" Height="160" Margin="5" AcceptsReturn="True" TextWrapping="Wrap" VerticalScrollBarVisibility="Auto" />
    <Button x:Name="saveShoppingListButton" Content="Save Shopping List" Margin="5" Click="SaveShoppingListButton_Click" />
</StackPanel>

Replace the existing textOutput line with the version below so the output area appears below the shopping list.

<TextBox x:Name="textOutput" HorizontalAlignment="Center" Height="170" Margin="0,480,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="300" BorderThickness="3" BorderBrush="#FFB3B3B4" />

Check Your Work

1. Build the solution
2. Run the application
3. Verify the existing 0.3 controls still appear
4. Verify the new School Shopping List text area and Save Shopping List button appear
5. Type several simple items such as Notebook, Pens, and USB cable, one per line

4. Observe Information While the Program Is Running

Before saving anything, notice where the shopping-list information exists. You typed the text into a control in a running application. At this moment, the program can use the value, but you have not yet demonstrated that it will survive after the program stops.

Step 1 — Add the file namespace

Open MainWindow.xaml.cs. Add the following line with the other using statements near the top of the file.

using System.IO;

Step 2 — Add the supplied Save handler

Scroll to the bottom of the MainWindow class. Add the following event handler after the existing event handlers and before the closing brace of MainWindow.

/// <summary>
/// Saves the school shopping list to a text file.
/// </summary>
/// <param name="sender">The object that initiated the event.</param>
/// <param name="e">The event arguments for the event.</param>
private void SaveShoppingListButton_Click(object sender, RoutedEventArgs e)
{
    File.WriteAllText("ShoppingList.txt", this.shoppingListTextBox.Text);
    this.textOutput.Text = "Shopping list saved.";
}

Step 3 — Pause before the file is written

1. Set a breakpoint on the File.WriteAllText line
2. Run the application
3. Enter several shopping-list items
4. Click Save Shopping List
5. When Visual Studio pauses, inspect this.shoppingListTextBox.Text

5. Save the Shopping List to a Text File

The supplied File.WriteAllText statement takes the current shopping-list text and writes it to a file named ShoppingList.txt. You are using the operation, not designing a file API.

Step 1 — Complete the save

1. At the breakpoint, verify the shopping-list text contains the items you entered
2. Press F10 to execute the File.WriteAllText statement
3. Continue the application
4. Verify the output area says Shopping list saved.

Step 2 — Find and inspect ShoppingList.txt

1. Use File Explorer to search within your 0.4 solution folder for ShoppingList.txt
2. Open the text file
3. Compare the file contents with the shopping list in the running application

Step 3 — Prove the information persists

1. Stop debugging and close the First Day application
2. Open ShoppingList.txt again
3. Verify the saved items are still present even though the application is no longer running

6. Read the Shopping List Back When the Program Opens

Saving proves the file survives. Reading the file when the application opens shows why persistent storage is useful: information from an earlier run can become part of a later run.

Step 1 — Add the supplied startup read-back code

Open MainWindow.xaml.cs and locate the MainWindow constructor. Place the following block immediately after this.InitializeComponent();.

if (File.Exists("ShoppingList.txt"))
{
    this.shoppingListTextBox.Text = File.ReadAllText("ShoppingList.txt");
}

Step 2 — Read the flow before running it

The activity diagram shows both possible startup paths. If the file exists, the application reads it. If the file does not exist, the shopping list simply begins empty.

Step 3 — Trace the read-back path

1. Make sure the ShoppingList.txt file you created earlier still exists
2. Set a breakpoint on if (File.Exists("ShoppingList.txt"))
3. Start the application
4. When the constructor pauses, predict whether the if block should run
5. Use F10 to step through the file check and the File.ReadAllText statement
6. Continue running the application

Check Your Work

1. The shopping-list items saved during the earlier run should appear again
2. You should not need to retype those items
3. The restored text should match the contents of ShoppingList.txt

Step 4 — Observe the no-file path

1. Close the application
2. Temporarily rename ShoppingList.txt to ShoppingList-old.txt
3. Start the application again
4. Verify the shopping-list area starts empty because ShoppingList.txt does not exist
5. Close the application and rename the file back to ShoppingList.txt

7. Final Check and Submit

Verify the complete 0.4 checkpoint before packaging the solution.

Step 1 — Complete the final technical check

1. Build the solution and correct any in-scope build errors.
2. Verify all existing 0.3 controls still work.
3. Enter a shopping list and save it to ShoppingList.txt.
4. Close and reopen the application and verify the saved list is restored.
5. Confirm the saved file contains the same shopping-list text shown in the application.

Step 2 — Zip the solution

1. Close Visual Studio
2. Locate the LastName parent folder that contains the .sln file and project folder
3. Create a ZIP file of the entire solution folder
4. Open the ZIP and confirm the solution file and FirstDayScenario project folder are present

Step 3 — Submit to the Feedback System

1. Open the Feedback System
2. Select the correct First Day 0.4 assignment
3. Upload the zipped Visual Studio solution
4. Review the Feedback System results and correct any in-scope issues if required
5. Resubmit a corrected ZIP when needed

Step 4 — Submit the Feedback System URL to Canvas

1. After the required Feedback System submission is ready, copy its URL
2. Open the correct 0.4 First Day Assignment in Canvas
3. Submit the Feedback System URL as your Canvas submission

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