Merge pull request #111 from irihitech/form

Form

src/Ursa/Controls/Form/Form.cs

@@ -0,0 +1,76 @@
+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
+{
+    public const string PC_FixedWidth = ":fixed-width";
+    
+    public static readonly StyledProperty<GridLength> LabelWidthProperty = AvaloniaProperty.Register<Form, GridLength>(
+        nameof(LabelWidth));
+
+    /// <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), defaultValue: Position.Top);
+
+    public Position LabelPosition
+    {
+        get => GetValue(LabelPositionProperty);
+        set => SetValue(LabelPositionProperty, value);
+    }
+
+    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 not FormItem && item is not FormGroup;
+    }
+    
+    protected override Control CreateContainerForItemOverride(object? item, int index, object? recycleKey)
+    {
+        if (item is not Control control) return new FormItem();
+        return new FormItem()
+        {
+            Content = control,
+            [!FormItem.LabelProperty] = control[!FormItem.LabelProperty],
+            [!FormItem.IsRequiredProperty] = control[!FormItem.IsRequiredProperty],
+            [!FormItem.NoLabelProperty] = control[!FormItem.NoLabelProperty],
+        };
+    }
+}

src/Ursa/Controls/Form/FormGroup.cs

@@ -0,0 +1,26 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+
+namespace Ursa.Controls;
+
+public class FormGroup: HeaderedItemsControl
+{
+    protected override bool NeedsContainerOverride(object? item, int index, out object? recycleKey)
+    {
+        recycleKey = null;
+        return item is not FormItem;
+    }
+
+    protected override Control CreateContainerForItemOverride(object? item, int index, object? recycleKey)
+    {
+        if (item is not Control control) return new FormItem();
+        return new FormItem
+        {
+            Content = control,
+            [!FormItem.LabelProperty] = control[!FormItem.LabelProperty],
+            [!FormItem.IsRequiredProperty] = control[!FormItem.IsRequiredProperty],
+        };
+    }
+    
+}

src/Ursa/Controls/Form/FormItem.cs

@@ -0,0 +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 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 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 AttachedProperty<bool> NoLabelProperty =
+        AvaloniaProperty.RegisterAttached<FormItem, Control, bool>("NoLabel");
+
+    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<double> LabelWidthProperty = AvaloniaProperty.Register<FormItem, double>(
+        nameof(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()
+    {
+        PropertyToPseudoClassMixin.Attach<FormItem>(NoLabelProperty, PC_NoLabel);
+    }
+
+    protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
+    {
+        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();
+        }
+    }
+}