UWP API Reference - Basics | Windows Developer

Basics of UWP APIs

The Universal Windows Platform (UWP) provides a rich set of APIs for building modern, high-quality applications that can run across the Windows ecosystem. This section introduces the fundamental concepts and APIs that form the foundation of UWP development.

Core Concepts

Understanding these core concepts is crucial for effective UWP development:

XAML: Extensible Application Markup Language is used for defining the user interface of UWP applications. It allows for declarative UI design, separating presentation from logic.
C# / .NET: UWP applications are typically written in C# using the .NET framework. This provides a robust and familiar development environment.
WinRT (Windows Runtime): The underlying runtime that UWP applications interact with. It exposes system capabilities and services through APIs.
Package Manifest: Defines the application's identity, capabilities, and resources.

Application Model

The UWP application model governs how applications are packaged, activated, and managed. Key components include:

App Lifecycle: UWP apps have a defined lifecycle (activated, suspended, terminated) managed by the system.
Activation: How your app starts in response to user actions or system events.
Background Tasks: APIs for performing operations even when the app is not actively running.
Sandboxing: UWP apps run in a restricted environment to enhance security and stability.

Activation Example

The OnLaunched method in your App.xaml.cs is the primary entry point for an activated application.

                
public partial class App : Application
{
    protected override void OnLaunched(LaunchActivatedEventArgs e)
    {
        if (e.PrelaunchActivated == false)
        {
            Frame rootFrame = Window.Current.Content as Frame;
            if (rootFrame == null)
            {
                rootFrame = new Frame();
                Window.Current.Content = rootFrame;
            }
            rootFrame.Navigate(typeof(MainPage), e.Arguments);
        }
        Window.Current.Activate();
    }
}
                
            

UI and Controls

UWP provides a comprehensive set of UI elements and layout panels for creating responsive and visually appealing interfaces.

Standard Controls: Buttons, TextBoxes, Lists, Grids, and more are available in the Windows.UI.Xaml.Controls namespace.
Layout Panels: Grid, StackPanel, RelativePanel, and Canvas help arrange your UI elements.
Data Binding: A powerful mechanism to connect UI elements to your application's data source, enabling dynamic updates.
Styling and Templating: Customize the appearance and behavior of controls using Styles and ControlTemplates.

XAML Button Example

                
<Button Content="Click Me" HorizontalAlignment="Center" VerticalAlignment="Center" />

Data Access

UWP offers various ways to store and retrieve data:

Local Storage: Use ApplicationData.Current.LocalSettings for simple key-value pairs or ApplicationData.Current.LocalFolder for files.
Roaming Storage: ApplicationData.Current.RoamingSettings and RoamingFolder allow data to sync across devices.
Databases: Integrate with SQLite or other databases for more complex data management.
RESTful Services: Fetch data from web APIs using HttpClient.

Local Settings Example

                
var localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
localSettings.Values["mySetting"] = "someValue";
object savedValue = localSettings.Values["mySetting"];

Communication

UWP enables various communication patterns:

Application-to-Application Communication: Through protocols like URI schemes, file associations, and transferable data.
Network Communication: Using HttpClient for RESTful services, WebSockets, and other network protocols.
Device Communication: Interact with Bluetooth, NFC, and other hardware.

Next Steps

This overview covers the basics. To delve deeper, explore the following resources: