ShrlAlgoToolkit/WPFluent/Controls/Flyout/Flyout.cs




using System.Windows.Controls.Primitives;


// ReSharper disable once CheckNamespace
namespace WPFluent.Controls;

/// <summary>
/// Represents a control that creates a pop-up window that displays information for an element in the interface.
/// </summary>
[TemplatePart(Name = "PART_Popup", Type = typeof(Popup))]
public class Flyout : System.Windows.Controls.ContentControl
{
    private const string ElementPopup = "PART_Popup";

    /// <summary>
    /// Identifies the <see cref="Closed"/> routed event.
    /// </summary>
    public static readonly RoutedEvent ClosedEvent = EventManager.RegisterRoutedEvent(
        nameof(Closed),
        RoutingStrategy.Bubble,
        typeof(TypedEventHandler<Flyout, RoutedEventArgs>),
        typeof(Flyout));

    /// <summary>
    /// Identifies the <see cref="IsOpen"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty IsOpenProperty = DependencyProperty.Register(
        nameof(IsOpen),
        typeof(bool),
        typeof(Flyout),
        new PropertyMetadata(false));

    /// <summary>
    /// Identifies the <see cref="Opened"/> routed event.
    /// </summary>
    public static readonly RoutedEvent OpenedEvent = EventManager.RegisterRoutedEvent(
        nameof(Opened),
        RoutingStrategy.Bubble,
        typeof(TypedEventHandler<Flyout, RoutedEventArgs>),
        typeof(Flyout));

    /// <summary>
    /// Identifies the <see cref="Placement"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty PlacementProperty = DependencyProperty.Register(
        nameof(Placement),
        typeof(PlacementMode),
        typeof(Flyout),
        new PropertyMetadata(PlacementMode.Top));

    private Popup _popup = default;

    /// <summary>
    /// Event triggered when <see cref="Flyout"/> is opened.
    /// </summary>
    public event TypedEventHandler<Flyout, RoutedEventArgs> Closed
    {
        add => AddHandler(ClosedEvent, value);
        remove => RemoveHandler(ClosedEvent, value);
    }

    /// <summary>
    /// Event triggered when <see cref="Flyout"/> is opened.
    /// </summary>
    public event TypedEventHandler<Flyout, RoutedEventArgs> Opened
    {
        add => AddHandler(OpenedEvent, value);
        remove => RemoveHandler(OpenedEvent, value);
    }

    protected virtual void OnPopupClosed(object sender, EventArgs e)
    {
        Hide();
        RaiseEvent(new RoutedEventArgs(ClosedEvent, this));
    }

    protected virtual void OnPopupOpened(object sender, EventArgs e)
    { RaiseEvent(new RoutedEventArgs(OpenedEvent, this)); }

    public void Hide()
    {
        if(IsOpen)
        {
            SetCurrentValue(IsOpenProperty, false);
        }
    }

    /// <summary>
    /// Invoked whenever application code or an internal process, such as a rebuilding layout pass, calls the
    /// ApplyTemplate method.
    /// </summary>
    public override void OnApplyTemplate()
    {
        base.OnApplyTemplate();

        _popup = GetTemplateChild(ElementPopup) as Popup;

        if(_popup is null)
        {
            return;
        }

        _popup.Opened -= OnPopupOpened;
        _popup.Opened += OnPopupOpened;

        _popup.Closed -= OnPopupClosed;
        _popup.Closed += OnPopupClosed;
    }

    public void Show()
    {
        if(!IsOpen)
        {
            SetCurrentValue(IsOpenProperty, true);
        }
    }

    /// <summary>
    /// Gets or sets a value indicating whether a <see cref="Flyout"/> is visible.
    /// </summary>
    public bool IsOpen { get => (bool)GetValue(IsOpenProperty); set => SetValue(IsOpenProperty, value); }

    /// <summary>
    /// Gets or sets the orientation of the <see cref="Flyout"/> control when the control opens, and specifies the
    /// behavior of the <see cref="T:System.Windows.Controls.Primitives.Popup"/> control when it overlaps screen
    /// boundaries.
    /// </summary>
    [Bindable(true)]
    [Category("Layout")]
    public PlacementMode Placement
    {
        get => (PlacementMode)GetValue(PlacementProperty);
        set => SetValue(PlacementProperty, value);
    }
}