Avalonia/Perspex/Controls/Control.cs

// -----------------------------------------------------------------------
// <copyright file="Control.cs" company="Steven Kirk">
// Copyright 2014 MIT Licence. See licence.md for more information.
// </copyright>
// -----------------------------------------------------------------------

namespace Perspex.Controls
{
    using System;
    using System.Collections.Generic;
    using System.Collections.ObjectModel;
    using System.Linq;
    using System.Reactive.Linq;
    using Perspex.Input;
    using Perspex.Layout;
    using Perspex.Media;
    using Perspex.Styling;
    using Splat;

    public class Control : Interactive, IFocusable, ILogical, IStyleable, IStyled
    {
        public static readonly PerspexProperty<Brush> BackgroundProperty =
            PerspexProperty.Register<Control, Brush>("Background", inherits: true);

        public static readonly PerspexProperty<Brush> BorderBrushProperty =
            PerspexProperty.Register<Control, Brush>("BorderBrush");

        public static readonly PerspexProperty<double> BorderThicknessProperty =
            PerspexProperty.Register<Control, double>("BorderThickness");

        public static readonly PerspexProperty<bool> FocusableProperty =
            PerspexProperty.Register<Control, bool>("Focusable");

        public static readonly PerspexProperty<double> FontSizeProperty =
            PerspexProperty.Register<Control, double>(
                "FontSize",
                defaultValue: 12.0,
                inherits: true);

        public static readonly PerspexProperty<Brush> ForegroundProperty =
            PerspexProperty.Register<Control, Brush>("Foreground", new SolidColorBrush(0xff000000), true);

        public static readonly PerspexProperty<bool> IsFocusedProperty =
            PerspexProperty.Register<Control, bool>("IsFocused", false);

        public static readonly PerspexProperty<bool> IsPointerOverProperty =
            PerspexProperty.Register<Control, bool>("IsPointerOver");

        public static readonly PerspexProperty<Control> ParentProperty =
            PerspexProperty.Register<Control, Control>("Parent");

        public static readonly RoutedEvent<RoutedEventArgs> GotFocusEvent =
            RoutedEvent.Register<Control, RoutedEventArgs>("GotFocus", RoutingStrategy.Bubble);

        public static readonly RoutedEvent<RoutedEventArgs> LostFocusEvent =
            RoutedEvent.Register<Control, RoutedEventArgs>("LostFocus", RoutingStrategy.Bubble);

        public static readonly RoutedEvent<KeyEventArgs> KeyDownEvent =
            RoutedEvent.Register<Control, KeyEventArgs>("KeyDown", RoutingStrategy.Bubble);

        public static readonly RoutedEvent<PointerEventArgs> PointerEnterEvent =
            RoutedEvent.Register<Control, PointerEventArgs>("PointerEnter", RoutingStrategy.Direct);

        public static readonly RoutedEvent<PointerEventArgs> PointerLeaveEvent =
            RoutedEvent.Register<Control, PointerEventArgs>("PointerLeave", RoutingStrategy.Direct);

        public static readonly RoutedEvent<PointerEventArgs> PointerPressedEvent =
            RoutedEvent.Register<Control, PointerEventArgs>("PointerPressed", RoutingStrategy.Bubble);

        public static readonly RoutedEvent<PointerEventArgs> PointerReleasedEvent =
            RoutedEvent.Register<Control, PointerEventArgs>("PointerReleased", RoutingStrategy.Bubble);

        private Classes classes;

        private string id;

        private Styles styles;

        static Control()
        {
            AffectsMeasure(IsVisibleProperty);
        }

        public Control()
        {
            this.classes = new Classes();
            this.GotFocus += (s, e) => this.IsFocused = true;
            this.LostFocus += (s, e) => this.IsFocused = false;
            this.PointerEnter += (s, e) => this.IsPointerOver = true;
            this.PointerLeave += (s, e) => this.IsPointerOver = false;
            this.AddPseudoClass(IsPointerOverProperty, ":pointerover");
            this.AddPseudoClass(IsFocusedProperty, ":focus");
        }

        public event EventHandler<RoutedEventArgs> GotFocus
        {
            add { this.AddHandler(GotFocusEvent, value); }
            remove { this.RemoveHandler(GotFocusEvent, value); }
        }

        public event EventHandler<RoutedEventArgs> LostFocus
        {
            add { this.AddHandler(LostFocusEvent, value); }
            remove { this.RemoveHandler(LostFocusEvent, value); }
        }

        public event EventHandler<KeyEventArgs> KeyDown
        {
            add { this.AddHandler(KeyDownEvent, value); }
            remove { this.RemoveHandler(KeyDownEvent, value); }
        }

        public event EventHandler<PointerEventArgs> PointerEnter
        {
            add { this.AddHandler(PointerEnterEvent, value); }
            remove { this.RemoveHandler(PointerEnterEvent, value); }
        }

        public event EventHandler<PointerEventArgs> PointerLeave
        {
            add { this.AddHandler(PointerLeaveEvent, value); }
            remove { this.RemoveHandler(PointerLeaveEvent, value); }
        }

        public event EventHandler<PointerEventArgs> PointerPressed
        {
            add { this.AddHandler(PointerPressedEvent, value); }
            remove { this.RemoveHandler(PointerPressedEvent, value); }
        }

        public event EventHandler<PointerEventArgs> PointerReleased
        {
            add { this.AddHandler(PointerReleasedEvent, value); }
            remove { this.RemoveHandler(PointerReleasedEvent, value); }
        }

        public Brush Background
        {
            get { return this.GetValue(BackgroundProperty); }
            set { this.SetValue(BackgroundProperty, value); }
        }

        public Brush BorderBrush
        {
            get { return this.GetValue(BorderBrushProperty); }
            set { this.SetValue(BorderBrushProperty, value); }
        }

        public double BorderThickness
        {
            get { return this.GetValue(BorderThicknessProperty); }
            set { this.SetValue(BorderThicknessProperty, value); }
        }

        public Classes Classes
        {
            get 
            {
                return this.classes; 
            }
            
            set
            {
                if (this.classes != value)
                {
                    this.classes.Clear();
                    this.classes.Add(value);
                }
            }
        }

        public double FontSize
        {
            get { return this.GetValue(FontSizeProperty); }
            set { this.SetValue(FontSizeProperty, value); }
        }

        public bool Focusable
        {
            get { return this.GetValue(FocusableProperty); }
            set { this.SetValue(FocusableProperty, value); }
        }

        public Brush Foreground
        {
            get { return this.GetValue(ForegroundProperty); }
            set { this.SetValue(ForegroundProperty, value); }
        }

        public bool IsFocused
        {
            get { return this.GetValue(IsFocusedProperty); }
            private set { this.SetValue(IsFocusedProperty, value); }
        }

        public string Id
        {
            get
            {
                return this.id;
            }

            set
            {
                if (this.id != null)
                {
                    throw new InvalidOperationException("ID already set.");
                }

                if (((IVisual)this).VisualParent != null)
                {
                    throw new InvalidOperationException("Cannot set ID : control already added to tree.");
                }

                this.id = value;
            }
        }

        public bool IsPointerOver
        {
            get { return this.GetValue(IsPointerOverProperty); }
            internal set { this.SetValue(IsPointerOverProperty, value); }
        }

        public Control Parent
        {
            get { return this.GetValue(ParentProperty); }
            protected set { this.SetValue(ParentProperty, value); }
        }

        public Styles Styles
        {
            get
            {
                if (this.styles == null)
                {
                    this.styles = new Styles();
                }

                return this.styles;
            }

            set
            {
                this.styles = value;
            }
        }

        public ITemplatedControl TemplatedParent
        {
            get;
            internal set;
        }

        ILogical ILogical.LogicalParent
        {
            get { return this.Parent; }
            set { this.Parent = (Control)value; }
        }

        IEnumerable<ILogical> ILogical.LogicalChildren
        {
            get { return Enumerable.Empty<ILogical>(); }
        }

        public void Focus()
        {
            Locator.Current.GetService<IFocusManager>().Focus(this);
        }

        protected void AddPseudoClass(PerspexProperty<bool> property, string className)
        {
            this.GetObservable(property).Subscribe(x =>
            {
                if (x)
                {
                    this.classes.Add(className);
                }
                else
                {
                    this.classes.Remove(className);
                }
            });
        }

        protected override void AttachedToVisualTree()
        {
            IStyler styler = Locator.Current.GetService<IStyler>();
            styler.ApplyStyles(this);
            base.AttachedToVisualTree();
        }
    }
}