Suma 4.0

Start the integrated development environment Microsoft Visual Studio 2026, create a new project and name it Suma 4.0.

MainPage.xaml

This file contains the source code for the application's user interface design.

<!-- User Interface (UI): Suma 4.0 -->
<StackLayout Padding="20">

    <!-- Title -->
    <Label Text="Suma 4.0" FontSize="Large" />

    <!-- A -->
    <Label Text="A=" />
    <Entry x:Name="boxA" Keyboard="Numeric" />

    <!-- B -->
    <Label Text="B=" />
    <Entry x:Name="boxB" Keyboard="Numeric" />

    <!-- A+B -->
    <Label Text="A+B=" />
    <Entry x:Name="boxAB" Keyboard="Numeric" />

    <!-- Button -->
    <Button Text="Sum" Clicked="OnButtonClicked" />

</StackLayout>

MainPage.xaml.cs

This file contains the source code for the application's business logic.

// Business Logic (BL): Suma 4.0
public partial class MainPage : ContentPage
{
    // Constructor
    public MainPage()
    {
        InitializeComponent();
    }

    // Button Click Event Handler
    void OnButtonClicked(object sender, EventArgs args)
    {
        var A = int.Parse(this.boxA.Text);
        var B = int.Parse(this.boxB.Text);
        var C = A + B;
        boxAB.Text = C.ToString();
    }
}

Running the app

Run the application and test its functionality as shown in the figure below.

Fig. 4.9. Suma 4.0

Note

Do you notice similarities with the examples from Chapter 2? Try to implement all examples from Chapter 2 yourself, using the Multi-Platform App User Interface (MAUI) project type.