feat: add value validation.

demo/Ursa.Demo/Pages/EnumSelectorDemo.axaml

@@ -1,19 +1,30 @@
-<UserControl xmlns="https://github.com/avaloniaui"
-             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
-             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
-             mc:Ignorable="d" d:DesignWidth="800"
-             xmlns:vm="clr-namespace:Ursa.Demo.ViewModels;assembly=Ursa.Demo"
-             xmlns:u="https://irihi.tech/ursa"
-             x:DataType="vm:EnumSelectorDemoViewModel"
-             x:CompileBindings="True"
-             d:DesignHeight="450"
-             x:Class="Ursa.Demo.Pages.EnumSelectorDemo">
+<UserControl
+    x:Class="Ursa.Demo.Pages.EnumSelectorDemo"
+    xmlns="https://github.com/avaloniaui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:u="https://irihi.tech/ursa"
+    xmlns:vm="clr-namespace:Ursa.Demo.ViewModels;assembly=Ursa.Demo"
+    d:DesignHeight="450"
+    d:DesignWidth="800"
+    x:CompileBindings="True"
+    x:DataType="vm:EnumSelectorDemoViewModel"
+    mc:Ignorable="d">
     <StackPanel>
-        <TextBlock Text="Select Type"></TextBlock>
-        <ComboBox ItemsSource="{Binding Types}" DisplayMemberBinding="{Binding Name}" SelectedItem="{Binding SelectedType}"/>
-        <TextBlock Text="Select Value"></TextBlock>
-        <u:EnumSelector EnumType="{Binding SelectedType}" Value="{Binding Value}" />
-        <TextBlock Text="{Binding Value}"></TextBlock>
+        <ToggleSwitch Name="description" Content="Show Description" />
+        <TextBlock Text="Select Type" />
+        <ComboBox
+            Width="200"
+            DisplayMemberBinding="{Binding Name}"
+            ItemsSource="{Binding Types}"
+            SelectedItem="{Binding SelectedType}" />
+        <TextBlock Text="Select Value" />
+        <u:EnumSelector
+            Width="200"
+            DisplayDescription="{Binding #description.IsChecked}"
+            EnumType="{Binding SelectedType}"
+            Value="{Binding Value}" />
+        <TextBlock Text="{Binding Value}" />
     </StackPanel>
 </UserControl>

demo/Ursa.Demo/ViewModels/EnumSelectorDemoViewModel.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections.ObjectModel;
+using System.ComponentModel;
+using System.Windows.Input;
 using Avalonia.Animation;
 using Avalonia.Controls;
 using Avalonia.Data;
@@ -7,6 +9,7 @@ using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Layout;
 using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
 
 namespace Ursa.Demo.ViewModels;
 
@@ -50,6 +53,15 @@ public class EnumSelectorDemoViewModel: ObservableObject
             typeof(Key),
             typeof(KeyModifiers),
             typeof(RoutingStrategies),
+            typeof(CustomEnum),
         };
     }
+}
+
+public enum CustomEnum
+{
+    [Description("是")]
+    Yes,
+    [Description("否")]
+    No,
 }

src/Ursa.Themes.Semi/Controls/EnumSelector.axaml

@@ -4,10 +4,29 @@
     xmlns:u="https://irihi.tech/ursa">
     <!--  Add Resources Here  -->
     <ControlTheme x:Key="{x:Type u:EnumSelector}" TargetType="u:EnumSelector">
+        <Setter Property="HorizontalAlignment" Value="Left"></Setter>
         <Setter Property="Template">
             <ControlTemplate TargetType="u:EnumSelector">
-                <ComboBox ItemsSource="{TemplateBinding Values}" SelectedItem="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Value, Mode=TwoWay}" />
+                <ComboBox
+                    Width="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Bounds.Width}"
+                    Name="PART_ComboBox"
+                    ItemsSource="{TemplateBinding Values}"
+                    SelectedItem="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=SelectedValue, Mode=TwoWay}" />
             </ControlTemplate>
         </Setter>
+        <Style Selector="^[DisplayDescription=True] /template/ ComboBox">
+            <Setter Property="ItemTemplate">
+                <DataTemplate x:DataType="u:EnumItemTuple">
+                    <TextBlock Text="{Binding DisplayName}"></TextBlock>
+                </DataTemplate>
+            </Setter>
+        </Style>
+        <Style Selector="^[DisplayDescription=False] /template/ ComboBox">
+            <Setter Property="ItemTemplate">
+                <DataTemplate x:DataType="u:EnumItemTuple">
+                    <TextBlock Text="{Binding Value}"></TextBlock>
+                </DataTemplate>
+            </Setter>
+        </Style>
     </ControlTheme>
 </ResourceDictionary>

src/Ursa/Controls/EnumSelector/EnumSelector.cs

@@ -1,3 +1,4 @@
+using System.ComponentModel;
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Controls.Primitives;
@@ -5,6 +6,12 @@ using Avalonia.Data;
 
 namespace Ursa.Controls;
 
+public class EnumItemTuple
+{
+    public string? DisplayName { get; set; }
+    public object? Value { get; set; }
+}
+
 public class EnumSelector: TemplatedControl
 {
     public static readonly StyledProperty<Type?> EnumTypeProperty = AvaloniaProperty.Register<EnumSelector, Type?>(
@@ -23,45 +30,129 @@ public class EnumSelector: TemplatedControl
     }
 
     public static readonly StyledProperty<object?> ValueProperty = AvaloniaProperty.Register<EnumSelector, object?>(
-        nameof(Value), defaultBindingMode: BindingMode.TwoWay);
+        nameof(Value), defaultBindingMode: BindingMode.TwoWay, coerce:OnValueCoerce);
+
+    private static object? OnValueCoerce(AvaloniaObject o,  object? value)
+    {
+        if (o is not EnumSelector selector) return null;
+        if (value is null) return null;
+        if (value.GetType() != selector.EnumType) return null;
+        var first = selector.Values.FirstOrDefault(a => Equals(a.Value, value));
+        if (first is null) return null;
+        return value;
+    }
+
 
     public object? Value
     {
         get => GetValue(ValueProperty);
         set => SetValue(ValueProperty, value);
     }
+
+    private EnumItemTuple? _selectedValue;
+
+    public static readonly DirectProperty<EnumSelector, EnumItemTuple?> SelectedValueProperty = AvaloniaProperty.RegisterDirect<EnumSelector, EnumItemTuple?>(
+        nameof(SelectedValue), o => o.SelectedValue, (o, v) => o.SelectedValue = v);
+
+    public EnumItemTuple? SelectedValue
+    {
+        get => _selectedValue;
+        private set => SetAndRaise(SelectedValueProperty, ref _selectedValue, value);
+    }
     
-    public static readonly DirectProperty<EnumSelector, IList<object?>?> ValuesProperty = AvaloniaProperty.RegisterDirect<EnumSelector, IList<object?>?>(
+    public static readonly DirectProperty<EnumSelector, IList<EnumItemTuple>?> ValuesProperty = AvaloniaProperty.RegisterDirect<EnumSelector, IList<EnumItemTuple>?>(
         nameof(Values), o => o.Values);
     
-    private IList<object?>? _values;
-    internal IList<object?>? Values
+    private IList<EnumItemTuple>? _values;
+    internal IList<EnumItemTuple>? Values
     {
         get => _values;
         private set => SetAndRaise(ValuesProperty, ref _values, value);
     }
-    
+
+    public static readonly StyledProperty<bool> DisplayDescriptionProperty = AvaloniaProperty.Register<EnumSelector, bool>(
+        nameof(DisplayDescription));
+
+    public bool DisplayDescription
+    {
+        get => GetValue(DisplayDescriptionProperty);
+        set => SetValue(DisplayDescriptionProperty, value);
+    }
     
     static EnumSelector()
     {
         EnumTypeProperty.Changed.AddClassHandler<EnumSelector, Type?>((o, e) => o.OnTypeChanged(e));
+        SelectedValueProperty.Changed.AddClassHandler<EnumSelector, EnumItemTuple?>((o, e) => o.OnSelectedValueChanged(e));
+        ValueProperty.Changed.AddClassHandler<EnumSelector, object?>((o, e) => o.OnValueChanged(e));
     }
 
+    private void OnValueChanged(AvaloniaPropertyChangedEventArgs<object?> args)
+    {
+        if (_updateFromComboBox) return;
+        var newValue = args.NewValue.Value;
+        if (newValue is null)
+        {
+            SetCurrentValue(SelectedValueProperty, null);
+        }
+        else
+        {
+            if (newValue.GetType() != EnumType)
+            {
+                SetCurrentValue(SelectedValueProperty, null);
+            }
+            var tuple = Values?.FirstOrDefault(x => Equals(x.Value, newValue));
+            SetCurrentValue(SelectedValueProperty, tuple);
+        }   
+    }
+
+    private bool _updateFromComboBox;
+
+    private void OnSelectedValueChanged(AvaloniaPropertyChangedEventArgs<EnumItemTuple?> args)
+    {
+        _updateFromComboBox = true;
+        var newValue = args.NewValue.Value;
+        SetCurrentValue(ValueProperty, newValue?.Value);
+        _updateFromComboBox = false;
+    }
+    
+    
+
     private void OnTypeChanged(AvaloniaPropertyChangedEventArgs<Type?> args)
     {
+        Values?.Clear();
         var newType = args.GetNewValue<Type?>();
         if (newType is null || !newType.IsEnum)
         {
             return;
         }
+        Values = GenerateItemTuple();
+    }
 
-        var values = Enum.GetValues(newType);
-        List<object?> list = new();
+    private List<EnumItemTuple> GenerateItemTuple()
+    {
+        if (EnumType is null) return new List<EnumItemTuple>();
+        var values = Enum.GetValues(EnumType);
+        List<EnumItemTuple> list = new();
+        var fields = EnumType.GetFields();
         foreach (var value in values)
         {
-            if (value.GetType() == newType)
-                list.Add(value);
+            if (value.GetType() == EnumType)
+            {
+                var displayName = value.ToString();
+                var field = EnumType.GetField(displayName);
+                var description = field?.GetCustomAttributes(typeof(DescriptionAttribute), false).FirstOrDefault();
+                if (description is not null)
+                {
+                    displayName = ((DescriptionAttribute) description).Description;
+                }
+                list.Add(new EnumItemTuple()
+                {
+                    DisplayName = displayName,
+                    Value = value
+                });
+            }
         }
-        Values = list;
+
+        return list;
     }
 }