PropertyGenerator.Avalonia 1.3.1

PropertyGenerator.Avalonia

Auto generate StyledProperty, DirectProperty, and AttachedProperty for Avalonia applications

StyledProperty

[GeneratedStyledProperty]
public partial int Count { get; set; }

Generated code:

StyledProperty<int> CountProperty = AvaloniaProperty.Register<MainWindow, int>(name: nameof(Count));
public partial int Count { get => GetValue(CountProperty); set => SetValue(CountProperty, value); }

[GeneratedStyledProperty(10)]
public partial int Count { get; set; }

Generated code:

Avalonia.StyledProperty<int> CountProperty = AvaloniaProperty.Register<MainWindow, int>(name: nameof(Count), defaultValue: 10);
public partial int Count { get => GetValue(CountProperty); set => SetValue(CountProperty, value); }

[GeneratedStyledProperty(
    DefaultValueCallback = nameof(DefaultValueCallback),
    DefaultValue = true,
    Validate = nameof(Validate),
    Coerce = nameof(Coerce),
    EnableDataValidation = true,
    Inherits = true,
    DefaultBindingMode = BindingMode.TwoWay)]
public partial bool? IsStarted { get; set; }

private static bool DefaultValueCallback()
{
    return true;
}
private static bool Validate(bool? value)
{
    return true;
}
private static bool? Coerce(AvaloniaObject x, bool? y)
{
    return true;
}

Generated code:

StyledProperty<bool?> IsStartedProperty = AvaloniaProperty.Register<MainWindow, bool?>(
	name: nameof(IsStarted), 
	defaultValue: DefaultValueCallback(), 
	validate: Validate,
	coerce: Coerce, 
	enableDataValidation: true,
	inherits: true, 
	defaultBindingMode:BindingMode.TwoWay);
public partial bool? IsStarted { get => GetValue(IsStartedProperty); set => SetValue(IsStartedProperty, value); }

DirectProperty

Similar in usage to StyledProperty generator

[GeneratedDirectProperty]
public partial IEnumerable? Items { get; set; }

You can directly initialize DirectProperty

[GeneratedDirectProperty]
public partial IEnumerable? Items { get; set; } = new AvaloniaList<object>();

You can also customize Getter and Setter for DirectProperty

[GeneratedDirectProperty(Getter = nameof(Getter), Setter = nameof(Setter))]
public partial IEnumerable? Items { get; set; }
public static IEnumerable? Getter(MainWindow o) => o.Items;
public static void Setter(MainWindow o, IEnumerable? v) => o.Items = v;

Generated code:

public static readonly DirectProperty<MainWindow, IEnumerable?> ItemsProperty
    = AvaloniaProperty.RegisterDirect<MainWindow, IEnumerable?>(
    name: nameof(Items),
    getter: Getter, 
    setter: Setter);

public partial IEnumerable? Items { get => field; set => SetAndRaise(ItemsProperty, ref field, value); }

Attached Property

Define attached properties on a partial class by using GenerateAttachedProperty<THost, TValue>:

[GenerateAttachedProperty<Control, string>("Tag")]
public partial class MainWindow : AvaloniaObject
{
}

Generated code:

public static readonly AttachedProperty<string> TagProperty = RegisterTagProperty();

public static string GetTag(Control host) => host.GetValue(TagProperty);
public static void SetTag(Control host, string value) => host.SetValue(TagProperty, value);

You can configure default value and registration options:

[GenerateAttachedProperty<Control, bool>("IsBusy",
    DefaultValueCallback = nameof(GetDefaultIsBusy),
    Validate = nameof(ValidateIsBusy),
    Coerce = nameof(CoerceIsBusy),
    Inherits = true,
    DefaultBindingMode = BindingMode.TwoWay)]
public partial class MainWindow : AvaloniaObject
{
    private static bool GetDefaultIsBusy() => true;
    private static bool ValidateIsBusy(bool value) => value;
    private static bool CoerceIsBusy(Control host, bool value) => value;
}

By default, attached property generation also emits these static partial callbacks:

static partial void OnIsBusyPropertyChanged(Control host, AvaloniaPropertyChangedEventArgs e);
static partial void OnIsBusyPropertyChanged(Control host, bool newValue);
static partial void OnIsBusyPropertyChanged(Control host, bool oldValue, bool newValue);

Apply DoNotGenerateOnPropertyChangedAttribute to disable those callbacks.

OnPropertyChanged

By default, the generator will override OnPropertyChanged and generate property changed methods at the same time:

partial void OnCountPropertyChanged(int newValue);
partial void OnCountPropertyChanged(int oldValue, int newValue);
partial void OnCountPropertyChanged(AvaloniaPropertyChangedEventArgs e);

partial void OnPropertyChangedOverride(AvaloniaPropertyChangedEventArgs change);

protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
{
    base.OnPropertyChanged(change);
    switch (change.Property.Name)
    {
        case nameof(Count):
            OnCountPropertyChanged(change);
            OnCountPropertyChanged((int)change.NewValue);
            OnCountPropertyChanged((int)change.OldValue, (int)change.NewValue);
            break;
    }
	OnPropertyChangedOverride(change);
}

You can still handle all property changes by using OnPropertyChangedOverride method.

To generate property changed methods for properties in base class, you can use GenerateOnPropertyChangedAttribute on target class:

[GenerateOnPropertyChanged(nameof(Height))]
public partial class MainWindow : Window
{ ... }

To disable this feature, use DoNotGenerateOnPropertyChangedAttribute for class or assembly:

[DoNotGenerateOnPropertyChanged]
public partial class MainWindow : Window
{ ... }

[assembly: DoNotGenerateOnPropertyChanged]

Diagnostics