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>