Implement Control ownership and nice to have interfaces.

Dashboard/Controls/Container.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Collections.Specialized;
+using System.ComponentModel;
 using Dashboard.Drawing;
 using Dashboard.Events;
 using Dashboard.Layout;
@@ -8,21 +10,21 @@ using Dashboard.Pal;
 
 namespace Dashboard.Controls
 {
-    public class Container : Control, IList<Control>, ILayoutContainer
+    public class Container : Control, IList<Control>, ILayoutContainer, INotifyCollectionChanged
     {
         private readonly List<Control> _controls = new List<Control>();
 
+        public ContainerLayoutInfo ContainerLayout { get; } = new ContainerLayoutInfo();
+
         public int Count => _controls.Count;
 
         public bool IsReadOnly => false;
 
-        public ContainerLayoutInfo ContainerLayout { get; } = new ContainerLayoutInfo();
-
         ILayoutItem IReadOnlyList<ILayoutItem>.this[int index] => _controls[index];
 
         public event EventHandler<ContainerChildAddedEventArgs>? ChildAdded;
         public event EventHandler<ContainerChildRemovedEventArgs>? ChildRemoved;
-
+        public event NotifyCollectionChangedEventHandler? CollectionChanged;
 
         public Control this[int index]
         {
@@ -30,6 +32,11 @@ namespace Dashboard.Controls
             set => _controls[index] = value;
         }
 
+        public Container()
+        {
+            ContainerLayout.PropertyChanged += OnContainerLayoutChanged;
+        }
+
         protected override void ValidateLayout()
         {
             if (!IsLayoutEnabled || IsLayoutValid)
@@ -82,16 +89,17 @@ namespace Dashboard.Controls
             SetParent(this, item);
 
             _controls.Add(item);
-            ChildAdded?.Invoke(this, new ContainerChildAddedEventArgs(this, item));
+            OnChildAdded(item);
         }
 
         public void Clear()
         {
             foreach (Control control in this)
             {
-                ChildRemoved?.Invoke(this, new ContainerChildRemovedEventArgs(this, control));
+                OnChildRemoved(control, false);
             }
             _controls.Clear();
+            OnCollectionChanged(NotifyCollectionChangedAction.Reset);
         }
 
         public bool Contains(Control item)
@@ -109,7 +117,7 @@ namespace Dashboard.Controls
             if (!_controls.Remove(item))
                 return false;
 
-            ChildRemoved?.Invoke(this, new ContainerChildRemovedEventArgs(this, item));
+            OnChildRemoved(item);
             return true;
         }
 
@@ -123,17 +131,64 @@ namespace Dashboard.Controls
             SetParent(this, item);
 
             _controls.Insert(index, item);
-            ChildAdded?.Invoke(this, new ContainerChildAddedEventArgs(this, item));
+            OnChildAdded(item);
         }
 
         public void RemoveAt(int index)
         {
             Control child = _controls[index];
             _controls.RemoveAt(index);
-            ChildRemoved?.Invoke(this, new ContainerChildRemovedEventArgs(this, child));
+            OnChildRemoved(child);
         }
 
+        protected override void OnOwnerChanged(Form value)
+        {
+            base.OnOwnerChanged(value);
 
+            foreach (Control control in this)
+            {
+                SetOwner(control, value);
+            }
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            base.Dispose(disposing);
+
+            if (disposing)
+            {
+                Clear();
+            }
+
+            ContainerLayout.PropertyChanged -= OnContainerLayoutChanged;
+        }
+
+        protected virtual void OnChildAdded(Control item)
+        {
+            SetOwner(item, Owner ?? null);
+            ChildAdded?.Invoke(this, new ContainerChildAddedEventArgs(this, item));
+
+            OnCollectionChanged(NotifyCollectionChangedAction.Add);
+        }
+
+        protected virtual void OnChildRemoved(Control control, bool notifyCollectionChanged = true)
+        {
+            SetOwner(control, null!);
+            ChildRemoved?.Invoke(this, new ContainerChildRemovedEventArgs(this, control));
+            
+            if (notifyCollectionChanged)
+                OnCollectionChanged(NotifyCollectionChangedAction.Remove);
+        }
+
+        protected virtual void OnCollectionChanged(NotifyCollectionChangedAction action)
+        {
+            CollectionChanged?.Invoke(this, new NotifyCollectionChangedEventArgs(action));
+        }
+
+        private void OnContainerLayoutChanged(object? sender, PropertyChangedEventArgs ea)
+        {
+            OnPropertyChanged(nameof(ContainerLayout));
+        }
     }
 
     public class ContainerChildAddedEventArgs(Container parent, Control child) : EventArgs

Dashboard/Controls/Control.cs

@@ -13,27 +13,33 @@ namespace Dashboard.Controls
 {
     public class Control : IEventListener, ILayoutItem, IDisposable
     {
-        private Form? _owner = null;
+        public string? Id
-
+        {
-        public string? Id { get; set; }
+            get;
+            set => SetField(ref field, value);
+        }
 
         public Form Owner
         {
-            get => _owner ?? throw NoOwnerException;
+            get ;
             protected set
             {
-                _owner = value;
                 OnOwnerChanged(value);
+                SetField(ref field, value);
             }
-        }
+        } = null!;
 
-        public Control? Parent { get; private set; } = null;
+        public Control? Parent
+        {
+            get;
+            private set => SetField(ref field, value);
+        } = null;
         public bool Disposed { get; private set; }
         public virtual Box2d ClientArea => Layout.ComputedBox;
-        public bool IsFocused => _owner?.FocusedControl == this;
+        public bool IsFocused => Owner?.FocusedControl == this;
 
-        public Brush Background { get; set; } = new SolidColorBrush(Color.Transparent);
+        public Brush Background { get; set => SetField(ref field, value); } = new SolidColorBrush(Color.Transparent);
-        public Brush BorderBrush { get; set; } = new SolidColorBrush(Color.Black);
+        public Brush BorderBrush { get; set => SetField(ref field, value); } = new SolidColorBrush(Color.Black);
 
         public LayoutInfo Layout { get; } = new LayoutInfo();
         public bool IsLayoutEnabled { get; private set; } = true;
@@ -49,6 +55,11 @@ namespace Dashboard.Controls
         public event EventHandler? Disposing;
         public event EventHandler? Resized;
 
+        public Control()
+        {
+            Layout.PropertyChanged += LayoutChanged;
+        }
+
         public virtual Vector2 CalculateIntrinsicSize()
         {
             return Vector2.Zero;
@@ -74,7 +85,9 @@ namespace Dashboard.Controls
         {
             if (Disposed)
                 return;
+
             Disposed = true;
+            Layout.PropertyChanged -= LayoutChanged;
 
             Dispose(disposing);
 
@@ -134,23 +147,13 @@ namespace Dashboard.Controls
             FocusLost?.Invoke(sender, EventArgs.Empty);
         }
 
-        internal static void InvokeFocusGained(Form form, Control control)
-        {
-            control.OnFocusGained(form);
-        }
-
-        internal static void InvokeFocusLost(Form form, Control control)
-        {
-            control.OnFocusLost(form);
-        }
-
         protected virtual void OnResize()
         {
             Resized?.Invoke(this, EventArgs.Empty);
             InvalidateLayout();
         }
 
-        private void OnOwnerChanged(Form value)
+        protected virtual void OnOwnerChanged(Form value)
         {
             OwnerChanged?.Invoke(this, EventArgs.Empty);
         }
@@ -188,6 +191,26 @@ namespace Dashboard.Controls
             PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
         }
 
+        private void LayoutChanged(object? sender, PropertyChangedEventArgs ea)
+        {
+            OnPropertyChanged(nameof(Layout));
+        }
+
         protected static Exception NoOwnerException => new Exception("No form owns this control");
+
+        internal static void InvokeFocusGained(Form form, Control control)
+        {
+            control.OnFocusGained(form);
+        }
+
+        internal static void InvokeFocusLost(Form form, Control control)
+        {
+            control.OnFocusLost(form);
+        }
+
+        private protected static void SetOwner(Control item, Form owner)
+        {
+            item.Owner = owner;
+        }
     }
 }

Dashboard/Controls/Form.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Drawing;
-using System.Numerics;
 using Dashboard.Drawing;
 using Dashboard.Events;
 using Dashboard.Pal;
@@ -10,20 +9,18 @@ namespace Dashboard.Controls
 {
     public class Form : Container, IForm
     {
-        private string? _title = "Untitled Form";
         public IWindow Window { get; }
-
         public Image? WindowIcon { get; set; }
 
-        public string? Title
+        public string Title
         {
-            get => _title;
+            get;
             set
             {
-                _title = value;
+                field = value;
-                Window.Title = _title ?? "";
+                Window.Title = field ?? "";
-            }
             }
+        } = "Untitled Form";
         public Control? FocusedControl { get; private set; } = null;
 
         public override Box2d ClientArea
@@ -37,19 +34,11 @@ namespace Dashboard.Controls
         {
             Window = window;
             Window.Form = this;
-            Window.Title = _title;
+            Window.Title = Title;
             Window.EventRaised += WindowEventRaised;
             Background = new SolidColorBrush(Color.SlateGray);
         }
 
-        private void WindowEventRaised(object? sender, EventArgs e)
-        {
-            if (e is ResizeEventArgs)
-            {
-                InvalidateLayout();
-            }
-        }
-
         public void Focus(Control control)
         {
             if (FocusedControl != null)
@@ -108,5 +97,20 @@ namespace Dashboard.Controls
                     break;
             }
         }
+
+        protected override void OnChildAdded(Control item)
+        {
+            base.OnChildAdded(item);
+            
+            SetOwner(item, this);
+        }
+
+        private void WindowEventRaised(object? sender, EventArgs e)
+        {
+            if (e is ResizeEventArgs)
+            {
+                InvalidateLayout();
+            }
+        }
     }
 }