feat: add more properties.

demo/Directory.Build.props

@@ -1,6 +1,6 @@
 <Project>
   <PropertyGroup>
     <Nullable>enable</Nullable>
-    <AvaloniaVersion>11.0.0</AvaloniaVersion>
+    <AvaloniaVersion>11.0.9</AvaloniaVersion>
   </PropertyGroup>
 </Project>

demo/Ursa.Demo/Pages/FormDemo.axaml

@@ -1,27 +1,58 @@
-<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" d:DesignHeight="450"
-             xmlns:vm="clr-namespace:Ursa.Demo.ViewModels;assembly=Ursa.Demo"
-             xmlns:u="https://irihi.tech/ursa"
-             x:DataType="vm:FormDemoViewModel"
-             x:CompileBindings="True"
-             x:Class="Ursa.Demo.Pages.FormDemo">
+<UserControl
+    x:Class="Ursa.Demo.Pages.FormDemo"
+    xmlns="https://github.com/avaloniaui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:common="clr-namespace:Ursa.Common;assembly=Ursa"
+    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:FormDemoViewModel"
+    mc:Ignorable="d">
     <StackPanel>
-        <u:Form DataContext="{Binding Model}" LabelWidth="Auto">
+        <StackPanel>
+            <u:EnumSelector
+                Name="position"
+                EnumType="common:Position"
+                Value="{x:Static common:Position.Top}" />
+            <u:EnumSelector
+                Name="alignment"
+                EnumType="HorizontalAlignment"
+                Value="{x:Static HorizontalAlignment.Left}" />
+        </StackPanel>
+        <u:Form
+            DataContext="{Binding Model}"
+            LabelAlignment="{Binding #alignment.Value}"
+            LabelPosition="{Binding #position.Value}"
+            LabelWidth="*">
             <u:FormGroup Header="Information">
-                <TextBox u:Form.Label="Name" Text="{Binding Name}" Width="300"/>
-                <TextBox u:Form.Label="Email" Text="{Binding Email}" Width="300"/>
+                <TextBox
+                    Width="300"
+                    u:FormItem.IsRequired="True"
+                    u:FormItem.Label="Name"
+                    Text="{Binding Name}" />
+                <TextBox
+                    Width="300"
+                    u:FormItem.Label="Email"
+                    Text="{Binding Email}" />
             </u:FormGroup>
-            <u:FormItem>
-                <CalendarDatePicker u:Form.Label="Date" SelectedDate="{Binding Date}" />
+            <u:FormItem Label="Please select a Date">
+                <Calendar SelectedDate="{Binding Date}" />
+            </u:FormItem>
+            <u:FormItem Label="Click to Submit">
+                <Button Content="With Label" />
+            </u:FormItem>
+            <u:FormItem NoLabel="True">
+                <Button HorizontalAlignment="Left" Content="No Label" />
             </u:FormItem>
         </u:Form>
         <StackPanel>
-            <TextBlock Text="{Binding Model.Name}"></TextBlock>
-            <TextBlock Text="{Binding Model.Email}"></TextBlock>
-            <TextBlock Text="{Binding Model.Date}"></TextBlock>
+            <TextBlock Text="{Binding Model.Name}" />
+            <TextBlock Text="{Binding Model.Email}" />
+            <TextBlock Text="{Binding Model.Date}" />
         </StackPanel>
     </StackPanel>
 </UserControl>

demo/Ursa.Demo/Ursa.Demo.csproj

@@ -19,7 +19,7 @@
         <!--Condition below is needed to remove Avalonia.Diagnostics package from build output in Release configuration.-->
         <PackageReference Condition="'$(Configuration)' == 'Debug'" Include="Avalonia.Diagnostics" Version="$(AvaloniaVersion)" />
         <PackageReference Include="CommunityToolkit.Mvvm" Version="8.1.0" />
-        <PackageReference Include="Semi.Avalonia" Version="11.0.0" />
+        <PackageReference Include="Semi.Avalonia" Version="11.0.7" />
     </ItemGroup>
 
     <ItemGroup>

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

@@ -1,36 +1,97 @@
-<ResourceDictionary xmlns="https://github.com/avaloniaui"
-                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-                    xmlns:u="https://irihi.tech/ursa">
-    <!-- Add Resources Here -->
+<ResourceDictionary
+    xmlns="https://github.com/avaloniaui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:u="https://irihi.tech/ursa">
+    <!--  Add Resources Here  -->
     <ControlTheme x:Key="{x:Type u:Form}" TargetType="u:Form">
+        <Setter Property="Grid.IsSharedSizeScope" Value="False" />
+        <Setter Property="HorizontalAlignment" Value="Left" />
         <Setter Property="Template">
             <ControlTemplate TargetType="u:Form">
                 <DataValidationErrors>
-                    <ItemsPresenter ItemsPanel="{TemplateBinding ItemsPanel}"></ItemsPresenter>
+                    <ItemsPresenter ItemsPanel="{TemplateBinding ItemsPanel}" />
                 </DataValidationErrors>
             </ControlTemplate>
         </Setter>
+        <Style Selector="^:fixed-width">
+            <Setter Property="Grid.IsSharedSizeScope" Value="True" />
+        </Style>
     </ControlTheme>
-    
+
     <ControlTheme x:Key="{x:Type u:FormGroup}" TargetType="u:FormGroup">
         <Setter Property="Template">
             <ControlTemplate TargetType="u:FormGroup">
                 <StackPanel>
-                    <ContentPresenter Content="{TemplateBinding Header}"/>
-                    <ItemsPresenter ItemsPanel="{TemplateBinding ItemsPanel}"/>
+                    <ContentPresenter Content="{TemplateBinding Header}" FontWeight="Bold" />
+                    <Rectangle
+                        Height="1"
+                        Margin="0,8"
+                        HorizontalAlignment="Stretch"
+                        Fill="LightGray" />
+                    <ItemsPresenter ItemsPanel="{TemplateBinding ItemsPanel}" />
                 </StackPanel>
             </ControlTemplate>
         </Setter>
     </ControlTheme>
-    
+
     <ControlTheme x:Key="{x:Type u:FormItem}" TargetType="u:FormItem">
+        <Setter Property="Margin" Value="0 8" />
         <Setter Property="Template">
             <ControlTemplate TargetType="u:FormItem">
-                <StackPanel Orientation="Horizontal">
-                    <TextBlock Text="{TemplateBinding Label}" />
-                    <ContentPresenter Content="{TemplateBinding Content}"/>
+                <StackPanel>
+                    <StackPanel
+                        Name="PART_LabelPanel"
+                        Margin="0,0,0,4"
+                        HorizontalAlignment="{TemplateBinding LabelAlignment}"
+                        Orientation="Horizontal">
+                        <ContentPresenter Content="{TemplateBinding Label}" FontWeight="Bold" />
+                        <TextBlock
+                            Foreground="{DynamicResource SemiRed6}"
+                            IsVisible="{TemplateBinding IsRequired}"
+                            Text="*" />
+                    </StackPanel>
+                    <ContentPresenter Content="{TemplateBinding Content}" />
                 </StackPanel>
             </ControlTemplate>
         </Setter>
+        <Style Selector="^:not(:no-label):horizontal">
+            <Setter Property="Template">
+                <ControlTemplate TargetType="u:FormItem">
+                    <Grid RowDefinitions="*, *">
+                        <Grid.ColumnDefinitions>
+                            <ColumnDefinition Width="Auto" SharedSizeGroup="Label" />
+                            <ColumnDefinition Width="*" />
+                        </Grid.ColumnDefinitions>
+                        <Border
+                            Grid.Row="0"
+                            Grid.Column="0"
+                            Width="{TemplateBinding LabelWidth}">
+                            <StackPanel
+                                Name="PART_LabelPanel"
+                                Margin="8,8,8,0"
+                                HorizontalAlignment="{TemplateBinding LabelAlignment}"
+                                Orientation="Horizontal">
+                                <ContentPresenter Content="{TemplateBinding Label}" FontWeight="Bold" />
+                                <TextBlock
+                                    Foreground="{DynamicResource SemiRed6}"
+                                    IsVisible="{TemplateBinding IsRequired}"
+                                    Text="*" />
+                            </StackPanel>
+                        </Border>
+                        <ContentPresenter
+                            Grid.Row="0"
+                            Grid.Column="1"
+                            Content="{TemplateBinding Content}" />
+                    </Grid>
+                </ControlTemplate>
+            </Setter>
+        </Style>
+        <Style Selector="^:no-label">
+            <Setter Property="Template">
+                <ControlTemplate TargetType="u:FormItem">
+                    <ContentPresenter Content="{TemplateBinding Content}" />
+                </ControlTemplate>
+            </Setter>
+        </Style>
     </ControlTheme>
 </ResourceDictionary>

src/Ursa/Controls/Form/Form.cs

@@ -1,59 +1,65 @@
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Controls.Metadata;
+using Avalonia.Layout;
 using Ursa.Common;
 
 namespace Ursa.Controls;
 
+[PseudoClasses(PC_FixedWidth)]
 public class Form: ItemsControl
 {
-    #region Attached Properties
-
-    public static readonly AttachedProperty<object?> LabelProperty =
-        AvaloniaProperty.RegisterAttached<Form, Control, object?>("Label");
-    public static void SetLabel(Control obj, object? value) => obj.SetValue(LabelProperty, value);
-    public static object? GetLabel(Control obj) => obj.GetValue(LabelProperty);
+    public const string PC_FixedWidth = ":fixed-width";
     
+    public static readonly StyledProperty<GridLength> LabelWidthProperty = AvaloniaProperty.Register<Form, GridLength>(
+        nameof(LabelWidth));
 
-    public static readonly AttachedProperty<bool> IsRequiredProperty =
-        AvaloniaProperty.RegisterAttached<Form, Control, bool>("IsRequired");
-    public static void SetIsRequired(Control obj, bool value) => obj.SetValue(IsRequiredProperty, value);
-    public static bool GetIsRequired(Control obj) => obj.GetValue(IsRequiredProperty);
-
-    public static readonly AttachedProperty<GridLength> LabelWidthProperty =
-        AvaloniaProperty.RegisterAttached<Form, Control, GridLength>("LabelWidth");
-
-    public static void SetLabelWidth(Control obj, GridLength value) => obj.SetValue(LabelWidthProperty, value);
-    public static GridLength GetLabelWidth(Control obj) => obj.GetValue(LabelWidthProperty);
-
-    #endregion
-    
+    /// <summary>
+    /// Behavior:
+    /// <para>Fixed Width: all labels are with fixed length. </para>
+    /// <para>Star: all labels are aligned by max length. </para>
+    /// <para>Auto: labels are not aligned. </para>
+    /// </summary>
+    public GridLength LabelWidth
+    {
+        get => GetValue(LabelWidthProperty);
+        set => SetValue(LabelWidthProperty, value);
+    }
 
     public static readonly StyledProperty<Position> LabelPositionProperty = AvaloniaProperty.Register<Form, Position>(
-        nameof(LabelPosition));
-    /// <summary>
-    /// Only Left and Top work.
-    /// </summary>
+        nameof(LabelPosition), defaultValue: Position.Top);
+
     public Position LabelPosition
     {
         get => GetValue(LabelPositionProperty);
         set => SetValue(LabelPositionProperty, value);
     }
 
-    public static readonly StyledProperty<Position> LabelAlignmentProperty = AvaloniaProperty.Register<Form, Position>(
-        nameof(LabelAlignment));
-    /// <summary>
-    /// Only Left and Right work. 
-    /// </summary>
-    public Position LabelAlignment
+    public static readonly StyledProperty<HorizontalAlignment> LabelAlignmentProperty = AvaloniaProperty.Register<Form, HorizontalAlignment>(
+        nameof(LabelAlignment), defaultValue: HorizontalAlignment.Left);
+
+    public HorizontalAlignment LabelAlignment
     {
         get => GetValue(LabelAlignmentProperty);
         set => SetValue(LabelAlignmentProperty, value);
     }
 
+    static Form()
+    {
+        LabelWidthProperty.Changed.AddClassHandler<Form, GridLength>((x, args) => x.LabelWidthChanged(args));
+    }
+
+    private void LabelWidthChanged(AvaloniaPropertyChangedEventArgs<GridLength> args)
+    {
+        var newValue = args.NewValue.Value;
+        bool isFixed = newValue.IsStar || newValue.IsAbsolute;
+        PseudoClasses.Set(PC_FixedWidth, isFixed);
+    }
+
     protected override bool NeedsContainerOverride(object? item, int index, out object? recycleKey)
     {
         recycleKey = null;
-        return item is FormItem or FormGroup;
+        return item is not FormItem && item is not FormGroup;
     }
     
     protected override Control CreateContainerForItemOverride(object? item, int index, object? recycleKey)
@@ -62,27 +68,8 @@ public class Form: ItemsControl
         return new FormItem()
         {
             Content = control,
-            [!LabelProperty] = control.GetObservable(Form.LabelProperty).ToBinding(),
-            [!IsRequiredProperty] = control.GetObservable(Form.IsRequiredProperty).ToBinding(),
+            [!FormItem.LabelProperty] = control[!FormItem.LabelProperty],
+            [!FormItem.IsRequiredProperty] = control[!FormItem.IsRequiredProperty],
         };
     }
-
-    protected override void PrepareContainerForItemOverride(Control container, object? item, int index)
-    {
-        base.PrepareContainerForItemOverride(container, item, index);
-        if (container is FormGroup group)
-        {
-            if (!group.IsSet(FormGroup.LabelWidthProperty))
-            {
-                group[!LabelWidthProperty] = this.GetObservable(LabelWidthProperty).ToBinding();
-            }
-        }
-        else if (container is FormItem formItem)
-        {
-            if(!formItem.IsSet(FormItem.LabelWidthProperty))
-            {
-                formItem[!LabelWidthProperty] = this.GetObservable(LabelWidthProperty).ToBinding();
-            }
-        }
-    }
 }

src/Ursa/Controls/Form/FormGroup.cs

@@ -6,13 +6,6 @@ namespace Ursa.Controls;
 
 public class FormGroup: HeaderedItemsControl
 {
-    public static readonly StyledProperty<GridLength> LabelWidthProperty = Form.LabelWidthProperty.AddOwner<FormGroup>();
-
-    public GridLength LabelWidth
-    {
-        get => GetValue(LabelWidthProperty);
-        set => SetValue(LabelWidthProperty, value);
-    }
     protected override bool NeedsContainerOverride(object? item, int index, out object? recycleKey)
     {
         recycleKey = null;
@@ -25,17 +18,9 @@ public class FormGroup: HeaderedItemsControl
         return new FormItem
         {
             Content = control,
-            [!FormItem.LabelProperty] = control.GetObservable(Form.LabelProperty).ToBinding(),
-            [!FormItem.IsRequiredProperty] = control.GetObservable(Form.IsRequiredProperty).ToBinding(),
+            [!FormItem.LabelProperty] = control[!FormItem.LabelProperty],
+            [!FormItem.IsRequiredProperty] = control[!FormItem.IsRequiredProperty],
         };
     }
-
-    protected override void PrepareContainerForItemOverride(Control container, object? item, int index)
-    {
-        base.PrepareContainerForItemOverride(container, item, index);
-        if (container is FormItem formItem)
-        {
-            formItem.LabelWidth = LabelWidth;
-        }
-    }
+    
 }

src/Ursa/Controls/Form/FormItem.cs

@@ -1,46 +1,93 @@
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Controls.Metadata;
 using Avalonia.Controls.Primitives;
+using Avalonia.Layout;
+using Avalonia.Reactive;
+using Avalonia.VisualTree;
+using Irihi.Avalonia.Shared.Helpers;
+using Ursa.Common;
 
 namespace Ursa.Controls;
 
+[PseudoClasses(PC_Horizontal, PC_NoLabel)]
 public class FormItem: ContentControl
 {
-    public static readonly StyledProperty<object?> LabelProperty = AvaloniaProperty.Register<FormItem, object?>(
-        nameof(Label));
+    public const string PC_Horizontal = ":horizontal";
+    public const string PC_NoLabel = ":no-label";
+    
+    #region Attached Properties
+    public static readonly AttachedProperty<object?> LabelProperty =
+        AvaloniaProperty.RegisterAttached<FormItem, Control, object?>("Label");
+    public static void SetLabel(Control obj, object? value) => obj.SetValue(LabelProperty, value);
+    public static object? GetLabel(Control obj) => obj.GetValue(LabelProperty);
+    
 
-    public object? Label
-    {
-        get => GetValue(LabelProperty);
-        set => SetValue(LabelProperty, value);
-    }
+    public static readonly AttachedProperty<bool> IsRequiredProperty =
+        AvaloniaProperty.RegisterAttached<FormItem, Control, bool>("IsRequired");
+    public static void SetIsRequired(Control obj, bool value) => obj.SetValue(IsRequiredProperty, value);
+    public static bool GetIsRequired(Control obj) => obj.GetValue(IsRequiredProperty);
 
-    public static readonly StyledProperty<bool> IsRequiredProperty = AvaloniaProperty.Register<FormItem, bool>(
-        nameof(IsRequired));
+    public static readonly AttachedProperty<bool> NoLabelProperty =
+        AvaloniaProperty.RegisterAttached<FormItem, Control, bool>("NoLabel");
 
-    public bool IsRequired
-    {
-        get => GetValue(IsRequiredProperty);
-        set => SetValue(IsRequiredProperty, value);
-    }
+    public static void SetNoLabel(Control obj, bool value) => obj.SetValue(NoLabelProperty, value);
+    public static bool GetNoLabel(Control obj) => obj.GetValue(NoLabelProperty);
+    #endregion
+    
+    private List<IDisposable> _formSubscriptions = new List<IDisposable>();
 
-    public static readonly StyledProperty<GridLength> LabelWidthProperty = AvaloniaProperty.Register<FormItem, GridLength>(
+    public static readonly StyledProperty<double> LabelWidthProperty = AvaloniaProperty.Register<FormItem, double>(
         nameof(LabelWidth));
 
-    public GridLength LabelWidth
+    public double LabelWidth
     {
         get => GetValue(LabelWidthProperty);
         set => SetValue(LabelWidthProperty, value);
     }
+
+    public static readonly StyledProperty<HorizontalAlignment> LabelAlignmentProperty = AvaloniaProperty.Register<FormItem, HorizontalAlignment>(
+        nameof(LabelAlignment));
+
+    public HorizontalAlignment LabelAlignment
+    {
+        get => GetValue(LabelAlignmentProperty);
+        set => SetValue(LabelAlignmentProperty, value);
+    }
     
     static FormItem()
     {
-        LabelWidthProperty.Changed.AddClassHandler<FormItem, GridLength>((x, args) => x.LabelWidthChanged(args));
+        PropertyToPseudoClassMixin.Attach<FormItem>(NoLabelProperty, PC_NoLabel);
     }
 
-    private void LabelWidthChanged(AvaloniaPropertyChangedEventArgs<GridLength> args)
+    protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
     {
-        GridLength? length = args.GetNewValue<GridLength>();
-        
+        base.OnAttachedToVisualTree(e);
+        var form = this.GetVisualAncestors().OfType<Form>().FirstOrDefault();
+        if (form is not null)
+        {
+            _formSubscriptions.Clear();
+            var labelSubscription = form
+                .GetObservable(Form.LabelWidthProperty)
+                .Subscribe(new AnonymousObserver<GridLength>(length => { LabelWidth = length.IsAbsolute ? length.Value : double.NaN; }));
+            var positionSubscription = form
+                .GetObservable(Form.LabelPositionProperty)
+                .Subscribe(new AnonymousObserver<Position>(position => { PseudoClasses.Set(PC_Horizontal, position == Position.Left);}));
+            var alignmentSubscription = form
+                .GetObservable(Form.LabelAlignmentProperty)
+                .Subscribe(new AnonymousObserver<HorizontalAlignment>(alignment => { LabelAlignment = alignment; }));
+            _formSubscriptions.Add(labelSubscription);
+            _formSubscriptions.Add(positionSubscription);
+            _formSubscriptions.Add(alignmentSubscription);
+        }
+    }
+
+    protected override void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
+    {
+        base.OnDetachedFromVisualTree(e);
+        foreach (var subscription in _formSubscriptions)
+        {
+            subscription.Dispose();
+        }
     }
 }

src/Ursa/Controls/Form/FormPanel.cs

@@ -1,6 +0,0 @@
-namespace Ursa.Controls;
-
-public class FormPanel
-{
-    
-}