UWP UI APIs

XAML Markup

The Extensible Application Markup Language (XAML) is the declarative language used to define UWP application UIs. It allows you to describe UI elements, their properties, and their relationships in a structured way.

XAML is a powerful tool for separating UI design from application logic, enabling designers and developers to work more efficiently.

<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
    <TextBlock Text="Hello, UWP!"
               HorizontalAlignment="Center"
               VerticalAlignment="Center"
               FontSize="32"
               Foreground="{ThemeResource SystemAccentColor}" />
</Grid>

Control Controls

UWP provides a rich set of standard controls that form the building blocks of your application's UI, including buttons, text boxes, lists, and more.

Key controls include:

• Button: For user interaction.
• TextBox: For text input.
• ListView/GridView: For displaying collections of data.
• ScrollViewer: For enabling scrolling.
• TextBlock/TextBlock: For displaying text.
• Image: For displaying images.

Layout Panels

Layout panels arrange child elements within a container, providing flexible and responsive layouts.

Common layout panels:

• Grid: Divides space into rows and columns.
• StackPanel: Arranges elements in a single line (horizontal or vertical).
• RelativePanel: Positions elements relative to siblings or the panel itself.
• Canvas: Allows absolute positioning of elements.

<RelativePanel Background="LightGray" Height="150">
    <Button Content="Top Left" RelativePanel.AlignLeftWithPanel="True"
            RelativePanel.AlignTopWithPanel="True" />
    <Button Content="Bottom Right" RelativePanel.AlignRightWithPanel="True"
            RelativePanel.AlignBottomWithPanel="True" />
</RelativePanel>

VisualStateManager

Manages the visual states of controls, allowing you to define different appearances and behaviors based on runtime conditions (e.g., hover, pressed, disabled).

Visual states are typically defined within a control's template in XAML.

<ControlTemplate TargetType="Button">
    <Border Background="{TemplateBinding Background}">
        <VisualStateManager.VisualStateGroups>
            <VisualStateGroup x:Name="CommonStates">
                <VisualState x:Name="Normal" />
                <VisualState x:Name="PointerOver">
                    <Storyboard>
                        <ColorAnimation Storyboard.TargetProperty="(Border.Background).(SolidColorBrush.Color)"
                                      To="LightBlue" />
                    </Storyboard>
                </VisualState>
                <!-- ... other states ... -->
            </VisualStateGroup>
        </VisualStateManager.VisualStateGroups>
        <ContentPresenter Content="{TemplateBinding Content}"
                          HorizontalAlignment="Center"
                          VerticalAlignment="Center" />
    </Border>
</ControlTemplate>

Resource Dictionaries and Styles

Define reusable styles, templates, and color resources in Resource Dictionaries to ensure UI consistency across your application.

Styles allow you to define a set of property values that can be applied to multiple elements. Theme resources provide access to system colors and brushes.

<!-- In App.xaml or a separate ResourceDictionary -->
<Style x:Key="MyButtonStyle" TargetType="Button">
    <Setter Property="Background" Value="DarkGreen" />
    <Setter Property="Foreground" Value="White" />
    <Setter Property="FontSize" Value="18" />
</Style>

<!-- In your page XAML -->
<Button Content="Click Me" Style="{StaticResource MyButtonStyle}" />

Composition API

The Composition API (part of the DirectX Graphics Infrastructure - DXGI) enables high-performance graphics and fluid animations.

Used for creating smooth visual effects, transitions, and immersive experiences.

Storyboard Animations

Define time-based animations directly in XAML to animate properties of UI elements.

Commonly used for transitions, transformations, and visual feedback.

<Page.Resources>
    <Storyboard x:Name="FadeInStoryboard">
        <DoubleAnimation Storyboard.TargetProperty="Opacity"
                         From="0.0" To="1.0" Duration="0:0:1" />
    </Storyboard>
</Page.Resources>

<!-- In your UI element -->
<TextBlock Text="Animated Text" Opacity="0" />

<!-- Trigger the animation, e.g., on Page load -->
<!-- ... code to start FadeInStoryboard ... -->