feat: bring code from Avalonia to Ursa.

src/Ursa/Common/ObservableHelper.cs

@@ -0,0 +1,38 @@
+using Avalonia.Reactive;
+
+namespace Ursa.Common;
+
+internal static class ObservableHelper
+{
+    public static IObservable<T> Skip<T>(this IObservable<T> source, int skipCount)
+    {
+        if (skipCount <= 0) throw new ArgumentException("Skip count must be bigger than zero", nameof(skipCount));
+
+        return Create<T>(obs =>
+        {
+            var remaining = skipCount;
+            return source.Subscribe(new AnonymousObserver<T>(
+                input =>
+                {
+                    if (remaining <= 0)
+                        obs.OnNext(input);
+                    else
+                        remaining--;
+                }, obs.OnError, obs.OnCompleted));
+        });
+    }
+
+    public static IObservable<TSource> Create<TSource>(Func<IObserver<TSource>, IDisposable> subscribe)
+    {
+        return new CreateWithDisposableObservable<TSource>(subscribe);
+    }
+
+    private sealed class CreateWithDisposableObservable<TSource>(Func<IObserver<TSource>, IDisposable> subscribe)
+        : IObservable<TSource>
+    {
+        public IDisposable Subscribe(IObserver<TSource> observer)
+        {
+            return subscribe(observer);
+        }
+    }
+}

src/Ursa/Common/XYFocusHelpers.cs

@@ -0,0 +1,23 @@
+using Avalonia.Input;
+
+namespace Ursa.Common;
+
+internal static class XYFocusHelpers
+{
+    internal static bool IsAllowedXYNavigationMode(this InputElement visual, KeyDeviceType? keyDeviceType)
+    {
+        return IsAllowedXYNavigationMode(XYFocus.GetNavigationModes(visual), keyDeviceType);
+    }
+
+    private static bool IsAllowedXYNavigationMode(XYFocusNavigationModes modes, KeyDeviceType? keyDeviceType)
+    {
+        return keyDeviceType switch
+        {
+            null => !modes.Equals(XYFocusNavigationModes.Disabled), // programmatic input, allow any subtree except Disabled.
+            KeyDeviceType.Keyboard => modes.HasFlag(XYFocusNavigationModes.Keyboard),
+            KeyDeviceType.Gamepad => modes.HasFlag(XYFocusNavigationModes.Gamepad),
+            KeyDeviceType.Remote => modes.HasFlag(XYFocusNavigationModes.Remote),
+            _ => throw new ArgumentOutOfRangeException(nameof(keyDeviceType), keyDeviceType, null)
+        };
+    }
+}

src/Ursa/Controls/AutoCompleteBox/MultiAutoCompleteBox.Properties.cs

@@ -0,0 +1,513 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using Avalonia;
+using Avalonia.Controls.Primitives;
+using Avalonia.Controls.Templates;
+using Avalonia.Controls;
+using Avalonia.Data;
+using Avalonia.Metadata;
+
+namespace Ursa.Controls;
+
+public partial class MultiAutoCompleteBox
+    {
+        /// <summary>
+        /// Defines see <see cref="TextBox.CaretIndex"/> property.
+        /// </summary>
+        public static readonly StyledProperty<int> CaretIndexProperty =
+            TextBox.CaretIndexProperty.AddOwner<MultiAutoCompleteBox>(new(
+                defaultValue: 0,
+                defaultBindingMode:BindingMode.TwoWay));
+
+        public static readonly StyledProperty<string?> WatermarkProperty =
+            TextBox.WatermarkProperty.AddOwner<MultiAutoCompleteBox>();
+
+        /// <summary>
+        /// Identifies the <see cref="MinimumPrefixLength" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="MinimumPrefixLength" /> property.</value>
+        public static readonly StyledProperty<int> MinimumPrefixLengthProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, int>(
+                nameof(MinimumPrefixLength), 1,
+                validate: IsValidMinimumPrefixLength);
+
+        /// <summary>
+        /// Identifies the <see cref="MinimumPopulateDelay" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="MinimumPopulateDelay" /> property.</value>
+        public static readonly StyledProperty<TimeSpan> MinimumPopulateDelayProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, TimeSpan>(
+                nameof(MinimumPopulateDelay),
+                TimeSpan.Zero,
+                validate: IsValidMinimumPopulateDelay);
+
+        /// <summary>
+        /// Identifies the <see cref="MaxDropDownHeight" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="MaxDropDownHeight" /> property.</value>
+        public static readonly StyledProperty<double> MaxDropDownHeightProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, double>(
+                nameof(MaxDropDownHeight),
+                double.PositiveInfinity,
+                validate: IsValidMaxDropDownHeight);
+
+        /// <summary>
+        /// Identifies the <see cref="IsTextCompletionEnabled" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="IsTextCompletionEnabled" /> property.</value>
+        public static readonly StyledProperty<bool> IsTextCompletionEnabledProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, bool>(
+                nameof(IsTextCompletionEnabled));
+
+        /// <summary>
+        /// Identifies the <see cref="ItemTemplate" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="ItemTemplate" /> property.</value>
+        public static readonly StyledProperty<IDataTemplate> ItemTemplateProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, IDataTemplate>(
+                nameof(ItemTemplate));
+
+        /// <summary>
+        /// Identifies the <see cref="IsDropDownOpen" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="IsDropDownOpen" /> property.</value>
+        public static readonly StyledProperty<bool> IsDropDownOpenProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, bool>(
+                nameof(IsDropDownOpen));
+
+        /// <summary>
+        /// Identifies the <see cref="SelectedItem" /> property.
+        /// </summary>
+        /// <value>The identifier the <see cref="SelectedItem" /> property.</value>
+        public static readonly StyledProperty<object?> SelectedItemProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, object?>(
+                nameof(SelectedItem),
+                defaultBindingMode: BindingMode.TwoWay,
+                enableDataValidation: true);
+
+        /// <summary>
+        /// Identifies the <see cref="Text" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="Text" /> property.</value>
+        public static readonly StyledProperty<string?> TextProperty =
+            TextBlock.TextProperty.AddOwner<MultiAutoCompleteBox>(new(string.Empty,
+                defaultBindingMode: BindingMode.TwoWay,
+                enableDataValidation: true));
+
+        /// <summary>
+        /// Identifies the <see cref="SearchText" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="SearchText" /> property.</value>
+        public static readonly DirectProperty<MultiAutoCompleteBox, string?> SearchTextProperty =
+            AvaloniaProperty.RegisterDirect<MultiAutoCompleteBox, string?>(
+                nameof(SearchText),
+                o => o.SearchText,
+                unsetValue: string.Empty);
+
+        /// <summary>
+        /// Gets the identifier for the <see cref="FilterMode" /> property.
+        /// </summary>
+        public static readonly StyledProperty<AutoCompleteFilterMode> FilterModeProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, AutoCompleteFilterMode>(
+                nameof(FilterMode),
+                defaultValue: AutoCompleteFilterMode.StartsWith,
+                validate: IsValidFilterMode);
+
+        /// <summary>
+        /// Identifies the <see cref="ItemFilter" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="ItemFilter" /> property.</value>
+        public static readonly StyledProperty<AutoCompleteFilterPredicate<object?>?> ItemFilterProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, AutoCompleteFilterPredicate<object?>?>(
+                nameof(ItemFilter));
+
+        /// <summary>
+        /// Identifies the <see cref="TextFilter" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="TextFilter" /> property.</value>
+        public static readonly StyledProperty<AutoCompleteFilterPredicate<string?>?> TextFilterProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, AutoCompleteFilterPredicate<string?>?>(
+                nameof(TextFilter),
+                defaultValue: AutoCompleteSearch.GetFilter(AutoCompleteFilterMode.StartsWith));
+
+        /// <summary>
+        /// Identifies the <see cref="ItemSelector" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="ItemSelector" /> property.</value>
+        public static readonly StyledProperty<AutoCompleteSelector<object>?> ItemSelectorProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, AutoCompleteSelector<object>?>(
+                nameof(ItemSelector));
+
+        /// <summary>
+        /// Identifies the <see cref="TextSelector" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="TextSelector" /> property.</value>
+        public static readonly StyledProperty<AutoCompleteSelector<string?>?> TextSelectorProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, AutoCompleteSelector<string?>?>(
+                nameof(TextSelector));
+
+        /// <summary>
+        /// Identifies the <see cref="ItemsSource" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="ItemsSource" /> property.</value>
+        public static readonly StyledProperty<IEnumerable?> ItemsSourceProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, IEnumerable?>(
+                nameof(ItemsSource));
+
+        /// <summary>
+        /// Identifies the <see cref="AsyncPopulator" /> property.
+        /// </summary>
+        /// <value>The identifier for the <see cref="AsyncPopulator" /> property.</value>
+        public static readonly StyledProperty<Func<string?, CancellationToken, Task<IEnumerable<object>>>?> AsyncPopulatorProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, Func<string?, CancellationToken, Task<IEnumerable<object>>>?>(
+                nameof(AsyncPopulator));
+
+        /// <summary>
+        /// Defines the <see cref="MaxLength"/> property
+        /// </summary>
+        public static readonly StyledProperty<int> MaxLengthProperty =
+            TextBox.MaxLengthProperty.AddOwner<MultiAutoCompleteBox>();
+
+        /// <summary>
+        /// Defines the <see cref="InnerLeftContent"/> property
+        /// </summary>
+        public static readonly StyledProperty<object?> InnerLeftContentProperty =
+            TextBox.InnerLeftContentProperty.AddOwner<MultiAutoCompleteBox>();
+
+        /// <summary>
+        /// Defines the <see cref="InnerRightContent"/> property
+        /// </summary>
+        public static readonly StyledProperty<object?> InnerRightContentProperty =
+            TextBox.InnerRightContentProperty.AddOwner<MultiAutoCompleteBox>();
+
+        /// <summary>
+        /// Gets or sets the caret index
+        /// </summary>
+        public int CaretIndex
+        {
+            get => GetValue(CaretIndexProperty);
+            set => SetValue(CaretIndexProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the minimum number of characters required to be entered
+        /// in the text box before the <see cref="AutoCompleteBox" /> displays possible matches.
+        /// </summary>
+        /// <value>
+        /// The minimum number of characters to be entered in the text box
+        /// before the <see cref="AutoCompleteBox" />
+        /// displays possible matches. The default is 1.
+        /// </value>
+        /// <remarks>
+        /// If you set MinimumPrefixLength to -1, the AutoCompleteBox will
+        /// not provide possible matches. There is no maximum value, but
+        /// setting MinimumPrefixLength to value that is too large will
+        /// prevent the AutoCompleteBox from providing possible matches as well.
+        /// </remarks>
+        public int MinimumPrefixLength
+        {
+            get => GetValue(MinimumPrefixLengthProperty);
+            set => SetValue(MinimumPrefixLengthProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the first possible match
+        /// found during the filtering process will be displayed automatically
+        /// in the text box.
+        /// </summary>
+        /// <value>
+        /// True if the first possible match found will be displayed
+        /// automatically in the text box; otherwise, false. The default is
+        /// false.
+        /// </value>
+        public bool IsTextCompletionEnabled
+        {
+            get => GetValue(IsTextCompletionEnabledProperty);
+            set => SetValue(IsTextCompletionEnabledProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the <see cref="T:Avalonia.DataTemplate" /> used
+        /// to display each item in the drop-down portion of the control.
+        /// </summary>
+        /// <value>The <see cref="T:Avalonia.DataTemplate" /> used to
+        /// display each item in the drop-down. The default is null.</value>
+        /// <remarks>
+        /// You use the ItemTemplate property to specify the visualization
+        /// of the data objects in the drop-down portion of the AutoCompleteBox
+        /// control. If your AutoCompleteBox is bound to a collection and you
+        /// do not provide specific display instructions by using a
+        /// DataTemplate, the resulting UI of each item is a string
+        /// representation of each object in the underlying collection.
+        /// </remarks>
+        public IDataTemplate ItemTemplate
+        {
+            get => GetValue(ItemTemplateProperty);
+            set => SetValue(ItemTemplateProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the minimum delay, after text is typed
+        /// in the text box before the
+        /// <see cref="AutoCompleteBox" /> control
+        /// populates the list of possible matches in the drop-down.
+        /// </summary>
+        /// <value>The minimum delay, after text is typed in
+        /// the text box, but before the
+        /// <see cref="AutoCompleteBox" /> populates
+        /// the list of possible matches in the drop-down. The default is 0.</value>
+        public TimeSpan MinimumPopulateDelay
+        {
+            get => GetValue(MinimumPopulateDelayProperty);
+            set => SetValue(MinimumPopulateDelayProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the maximum height of the drop-down portion of the
+        /// <see cref="AutoCompleteBox" /> control.
+        /// </summary>
+        /// <value>The maximum height of the drop-down portion of the
+        /// <see cref="AutoCompleteBox" /> control.
+        /// The default is <see cref="F:System.Double.PositiveInfinity" />.</value>
+        /// <exception cref="T:System.ArgumentException">The specified value is less than 0.</exception>
+        public double MaxDropDownHeight
+        {
+            get => GetValue(MaxDropDownHeightProperty);
+            set => SetValue(MaxDropDownHeightProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the drop-down portion of
+        /// the control is open.
+        /// </summary>
+        /// <value>
+        /// True if the drop-down is open; otherwise, false. The default is
+        /// false.
+        /// </value>
+        public bool IsDropDownOpen
+        {
+            get => GetValue(IsDropDownOpenProperty);
+            set => SetValue(IsDropDownOpenProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the  <see cref="T:Avalonia.Data.Binding" /> that
+        /// is used to get the values for display in the text portion of
+        /// the <see cref="AutoCompleteBox" />
+        /// control.
+        /// </summary>
+        /// <value>The <see cref="T:Avalonia.Data.IBinding" /> object used
+        /// when binding to a collection property.</value>
+        [AssignBinding]
+        [InheritDataTypeFromItems(nameof(ItemsSource))]
+        public IBinding? ValueMemberBinding
+        {
+            get => _valueBindingEvaluator?.ValueBinding;
+            set
+            {
+                if (ValueMemberBinding != value)
+                {
+                    _valueBindingEvaluator = new BindingEvaluator<string>(value);
+                    OnValueMemberBindingChanged(value);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets the selected item in the drop-down.
+        /// </summary>
+        /// <value>The selected item in the drop-down.</value>
+        /// <remarks>
+        /// If the IsTextCompletionEnabled property is true and text typed by
+        /// the user matches an item in the ItemsSource collection, which is
+        /// then displayed in the text box, the SelectedItem property will be
+        /// a null reference.
+        /// </remarks>
+        public object? SelectedItem
+        {
+            get => GetValue(SelectedItemProperty);
+            set => SetValue(SelectedItemProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the text in the text box portion of the
+        /// <see cref="AutoCompleteBox" /> control.
+        /// </summary>
+        /// <value>The text in the text box portion of the
+        /// <see cref="AutoCompleteBox" /> control.</value>
+        public string? Text
+        {
+            get => GetValue(TextProperty);
+            set => SetValue(TextProperty, value);
+        }
+
+        /// <summary>
+        /// Gets the text that is used to filter items in the
+        /// <see cref="ItemsSource" /> item collection.
+        /// </summary>
+        /// <value>The text that is used to filter items in the
+        /// <see cref="ItemsSource" /> item collection.</value>
+        /// <remarks>
+        /// The SearchText value is typically the same as the
+        /// Text property, but is set after the TextChanged event occurs
+        /// and before the Populating event.
+        /// </remarks>
+        public string? SearchText
+        {
+            get => _searchText;
+            private set
+            {
+                try
+                {
+                    _allowWrite = true;
+                    SetAndRaise(SearchTextProperty, ref _searchText, value);
+                }
+                finally
+                {
+                    _allowWrite = false;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets how the text in the text box is used to filter items
+        /// specified by the <see cref="ItemsSource" />
+        /// property for display in the drop-down.
+        /// </summary>
+        /// <value>One of the <see cref="AutoCompleteFilterMode" />
+        /// values The default is <see cref="AutoCompleteFilterMode.StartsWith" />.</value>
+        /// <exception cref="T:System.ArgumentException">The specified value is not a valid
+        /// <see cref="AutoCompleteFilterMode" />.</exception>
+        /// <remarks>
+        /// Use the FilterMode property to specify how possible matches are
+        /// filtered. For example, possible matches can be filtered in a
+        /// predefined or custom way. The search mode is automatically set to
+        /// Custom if you set the ItemFilter property.
+        /// </remarks>
+        public AutoCompleteFilterMode FilterMode
+        {
+            get => GetValue(FilterModeProperty);
+            set => SetValue(FilterModeProperty, value);
+        }
+
+        public string? Watermark
+        {
+            get => GetValue(WatermarkProperty);
+            set => SetValue(WatermarkProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the custom method that uses user-entered text to filter
+        /// the items specified by the <see cref="ItemsSource" />
+        /// property for display in the drop-down.
+        /// </summary>
+        /// <value>The custom method that uses the user-entered text to filter
+        /// the items specified by the <see cref="ItemsSource" />
+        /// property. The default is null.</value>
+        /// <remarks>
+        /// The filter mode is automatically set to Custom if you set the
+        /// ItemFilter property.
+        /// </remarks>
+        public AutoCompleteFilterPredicate<object?>? ItemFilter
+        {
+            get => GetValue(ItemFilterProperty);
+            set => SetValue(ItemFilterProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the custom method that uses the user-entered text to
+        /// filter items specified by the <see cref="ItemsSource" />
+        /// property in a text-based way for display in the drop-down.
+        /// </summary>
+        /// <value>The custom method that uses the user-entered text to filter
+        /// items specified by the <see cref="ItemsSource" />
+        /// property in a text-based way for display in the drop-down.</value>
+        /// <remarks>
+        /// The search mode is automatically set to Custom if you set the
+        /// TextFilter property.
+        /// </remarks>
+        public AutoCompleteFilterPredicate<string?>? TextFilter
+        {
+            get => GetValue(TextFilterProperty);
+            set => SetValue(TextFilterProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the custom method that combines the user-entered
+        /// text and one of the items specified by the <see cref="ItemsSource" />.
+        /// </summary>
+        /// <value>
+        /// The custom method that combines the user-entered
+        /// text and one of the items specified by the <see cref="ItemsSource" />.
+        /// </value>
+        public AutoCompleteSelector<object>? ItemSelector
+        {
+            get => GetValue(ItemSelectorProperty);
+            set => SetValue(ItemSelectorProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the custom method that combines the user-entered
+        /// text and one of the items specified by the
+        /// <see cref="ItemsSource" /> in a text-based way.
+        /// </summary>
+        /// <value>
+        /// The custom method that combines the user-entered
+        /// text and one of the items specified by the <see cref="ItemsSource" />
+        /// in a text-based way.
+        /// </value>
+        public AutoCompleteSelector<string?>? TextSelector
+        {
+            get => GetValue(TextSelectorProperty);
+            set => SetValue(TextSelectorProperty, value);
+        }
+
+        public Func<string?, CancellationToken, Task<IEnumerable<object>>>? AsyncPopulator
+        {
+            get => GetValue(AsyncPopulatorProperty);
+            set => SetValue(AsyncPopulatorProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets a collection that is used to generate the items for the
+        /// drop-down portion of the <see cref="AutoCompleteBox" /> control.
+        /// </summary>
+        /// <value>The collection that is used to generate the items of the
+        /// drop-down portion of the <see cref="AutoCompleteBox" /> control.</value>
+        public IEnumerable? ItemsSource
+        {
+            get => GetValue(ItemsSourceProperty);
+            set => SetValue(ItemsSourceProperty, value);
+        }
+       
+        /// <summary>
+        /// Gets or sets the maximum number of characters that the <see cref="AutoCompleteBox"/> can accept.
+        /// This constraint only applies for manually entered (user-inputted) text.
+        /// </summary>
+        public int MaxLength
+        {
+            get => GetValue(MaxLengthProperty);
+            set => SetValue(MaxLengthProperty, value);
+        }
+      
+        /// <summary>
+        /// Gets or sets custom content that is positioned on the left side of the text layout box
+        /// </summary>
+        public object? InnerLeftContent
+        {
+            get => GetValue(InnerLeftContentProperty);
+            set => SetValue(InnerLeftContentProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets custom content that is positioned on the right side of the text layout box
+        /// </summary>
+        public object? InnerRightContent
+        {
+            get => GetValue(InnerRightContentProperty);
+            set => SetValue(InnerRightContentProperty, value);
+        }      
+    }