Keyboard API Reference

Windows > API Reference > UWP > Input > Keyboard

This document provides a reference for the Universal Windows Platform (UWP) keyboard input APIs, allowing developers to capture and process keyboard events within their applications.

Core Concepts

The UWP keyboard input model is built around handling events that are dispatched when keys are pressed, released, or repeated. This allows for responsive and intuitive user interactions.

Key Events

• KeyDown: Fired when a key is pressed down.
• KeyUp: Fired when a key is released.
• KeyProcess: (Less common for direct handling, more for system-level processing)

Key Information

When a keyboard event occurs, you receive an object containing critical information such as:

• VirtualKey: Represents the physical key pressed (e.g., `VirtualKey.A`, `VirtualKey.Enter`).
• KeyStatus: Provides details about the state of modifier keys (Shift, Ctrl, Alt) and whether the key is repeating.
• Modifiers: A combination of modifier keys.

Classes and Structures

Example Usage

Here's a basic example of how to handle keyboard events in a UWP application using C#.

// Assuming you have a UI element (e.g., a Page or a specific control)
// that can receive keyboard input.

// In your XAML, ensure the element has KeyUp or KeyDown events wired up,
// or set the `IsFocusEnabled` property if needed.

// Example in C# code-behind:
public sealed partial class MainPage : Page
{
    public MainPage()
    {
        this.InitializeComponent();
        // Subscribe to the KeyDown event for the page
        this.KeyDown += MainPage_KeyDown;
        // Subscribe to the KeyUp event for the page
        this.KeyUp += MainPage_KeyUp;

        // Ensure the page can receive focus to handle keyboard events
        this.Focus(FocusState.Programmatic);
    }

    private void MainPage_KeyDown(object sender, KeyEventArgs e)
    {
        Debug.WriteLine($"Key Down: {e.VirtualKey}");

        // Example: Handle pressing the Enter key
        if (e.VirtualKey == VirtualKey.Enter)
        {
            Debug.WriteLine("Enter key pressed!");
            // Perform an action, e.g., submit a form
        }

        // Example: Check for modifier keys
        if (e.KeyStatus.IsControlPressed() && e.VirtualKey == VirtualKey.S)
        {
            Debug.WriteLine("Ctrl + S pressed (Save action)");
            // Trigger save operation
        }
    }

    private void MainPage_KeyUp(object sender, KeyEventArgs e)
    {
        Debug.WriteLine($"Key Up: {e.VirtualKey}");

        // Example: Handling a key release, perhaps to stop an action
        if (e.VirtualKey == VirtualKey.Space)
        {
            Debug.WriteLine("Spacebar released.");
        }
    }
}

// Helper extension methods for checking modifiers (can be defined elsewhere)
public static class KeyEventArgsExtensions
{
    public static bool IsModifierPressed(this CorePhysicalKeyStatus status)
    {
        return status.IsLeftShiftPressed || status.IsRightShiftPressed ||
               status.IsLeftControlPressed || status.IsRightControlPressed ||
               status.IsLeftAltPressed || status.IsRightAltPressed;
    }

    public static bool IsControlPressed(this CorePhysicalKeyStatus status)
    {
        return status.IsLeftControlPressed || status.IsRightControlPressed;
    }

    public static bool IsShiftPressed(this CorePhysicalKeyStatus status)
    {
        return status.IsLeftShiftPressed || status.IsRightShiftPressed;
    }

    public static bool IsAltPressed(this CorePhysicalKeyStatus status)
    {
        return status.IsLeftAltPressed || status.IsRightAltPressed;
    }
}
            

Related Topics

• Mouse Input
• Touch Input
• Pen Input
• Handling Input Events