DependencyPropertyGenerator

Dependency property source generator for WPF/UWP/WinUI/Uno/Avalonia platforms. For the WPF platform, RoutedEvents are also supported.

Install

Install-Package DependencyPropertyGenerator // Generator
Install-Package DependencyPropertyGenerator.Core // Attributes

Usage

using DependencyPropertyGenerator;
using System.Windows.Controls;

#nullable enable

namespace H.Generators.IntegrationTests;

[DependencyProperty<bool>("IsSpinning", DefaultValue = true, Category = "Category", Description = "Description")]
public partial class MyControl : UserControl
{
    // Optional
    partial void OnIsSpinningChanged(bool oldValue, bool newValue)
    {
    }
}

[AttachedDependencyProperty<object, TreeView>("SelectedItem", BindsTwoWayByDefault = true)]
public static partial class TreeViewExtensions
{
    // Optional
    static partial void OnSelectedItemChanged(TreeView sender, object? oldValue, object? newValue)
    {
    }
}

will generate:

//HintName: MyControl.Properties.IsSpinning.generated.cs

#nullable enable

namespace H.Generators.IntegrationTests
{
    public partial class MyControl
    {
        /// <summary>
        /// Description<br/>
        /// Default value: true
        /// </summary>
        public static readonly global::System.Windows.DependencyProperty IsSpinningProperty =
            global::System.Windows.DependencyProperty.Register(
                name: "IsSpinning",
                propertyType: typeof(bool),
                ownerType: typeof(global::H.Generators.IntegrationTests.MyControl),
                typeMetadata: new global::System.Windows.FrameworkPropertyMetadata(
                    defaultValue: (bool)true,
                    flags: global::System.Windows.FrameworkPropertyMetadataOptions.None,
                    propertyChangedCallback: static (sender, args) =>
                        ((global::H.Generators.IntegrationTests.MyControl)sender).OnIsSpinningChanged(
                            (bool)args.OldValue,
                            (bool)args.NewValue),
                    coerceValueCallback: null,
                    isAnimationProhibited: false),
                validateValueCallback: null);

        /// <summary>
        /// Description<br/>
        /// Default value: true
        /// </summary>
        [global::System.ComponentModel.Category("Category")]
        [global::System.ComponentModel.Description("Description")]
        public bool IsSpinning
        {
            get => (bool)GetValue(IsSpinningProperty);
            set => SetValue(IsSpinningProperty, value);
        }

        partial void OnIsSpinningChanged(bool oldValue, bool newValue);
    }
}

//HintName: TreeViewExtensions.AttachedProperties.SelectedItem.generated.cs

#nullable enable

namespace H.Generators.IntegrationTests
{
    public static partial class TreeViewExtensions
    {
        /// <summary>
        /// Default value: default(object)
        /// </summary>
        public static readonly global::System.Windows.DependencyProperty SelectedItemProperty =
            global::System.Windows.DependencyProperty.RegisterAttached(
                name: "SelectedItem",
                propertyType: typeof(object),
                ownerType: typeof(global::H.Generators.IntegrationTests.TreeViewExtensions),
                defaultMetadata: new global::System.Windows.FrameworkPropertyMetadata(
                    defaultValue: default(object),
                    flags: global::System.Windows.FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
                    propertyChangedCallback: static (sender, args) =>
                        OnSelectedItemChanged(
                            (global::System.Windows.Controls.TreeView)sender,
                            (object?)args.OldValue,
                            (object?)args.NewValue),
                    coerceValueCallback: null,
                    isAnimationProhibited: false),
                validateValueCallback: null);

        /// <summary>
        /// Default value: default(object)
        /// </summary>
        public static void SetSelectedItem(global::System.Windows.DependencyObject element, object? value)
        {
            element = element ?? throw new global::System.ArgumentNullException(nameof(element));

            element.SetValue(SelectedItemProperty, value);
        }

        /// <summary>
        /// Default value: default(object)
        /// </summary>
        [global::System.Windows.AttachedPropertyBrowsableForType(typeof(global::System.Windows.Controls.TreeView))]
        public static object? GetSelectedItem(global::System.Windows.DependencyObject element)
        {
            element = element ?? throw new global::System.ArgumentNullException(nameof(element));

            return (object?)element.GetValue(SelectedItemProperty);
        }

        static partial void OnSelectedItemChanged(global::System.Windows.Controls.TreeView sender, object? oldValue, object? newValue);
    }
}

Advanced usage

new object/struct() expressions in DefaultValue

While it's generally not recommended to use new expressions in properties, a generator provides this capability:

public readonly record struct Data();

[AttachedDependencyProperty<object, TreeView>("SelectedItem", DefaultValueExpression = "new Data()")]

If your type is declared outside the namespace of an attribute declaration, you will need to specify the full name of the type, including the namespace.

XML documentation

If for some reason you need to save xml documentation for your properties, there is an option to specify xml text for both DependencyProperty and getter/setter via XmlDocumentation/PropertyXmlDocumentation attribute properties.

Platform detection

For some platforms there is no automatic detection. In these cases, the generator needs a little help by adding:

  <PropertyGroup>
    <DefineConstants>$(DefineConstants);HAS_AVALONIA</DefineConstants>
  </PropertyGroup>

Bind event

The generator can automatically control properties that depend on events:

[AttachedDependencyProperty<object, Grid>("BindEventProperty", BindEvent = nameof(Grid.MouseWheel))]
public static partial class GridExtensions
{
    private static void OnBindEventPropertyChanged_MouseWheel(object? sender, System.Windows.Input.MouseWheelEventArgs args)
    {
    }
}

will generate additional code:

static partial void OnBindEventPropertyChanged_BeforeBind(
    global::System.Windows.Controls.Grid sender,
    object? oldValue,
    object? newValue);
static partial void OnBindEventPropertyChanged_AfterBind(
    global::System.Windows.Controls.Grid sender,
    object? oldValue,
    object? newValue);

static partial void OnBindEventPropertyChanged(
    global::System.Windows.Controls.Grid sender,
    object? oldValue,
    object? newValue)
{
    OnBindEventPropertyChanged_BeforeBind(
        sender,
        oldValue,
        newValue);

    if (oldValue is not default(object))
    {
        sender.MouseWheel -= OnBindEventPropertyChanged_MouseWheel;
    }
    if (newValue is not default(object))
    {
        sender.MouseWheel += OnBindEventPropertyChanged_MouseWheel;
    }

    OnBindEventPropertyChanged_AfterBind(
        sender,
        oldValue,
        newValue);
}

Notes

To use generic attributes, you need to set up LangVersion in your .csproj:

<LangVersion>preview</LangVersion>

There are also non-Generic attributes here.

Support

Priority place for bugs: https://github.com/HavenDV/DependencyPropertyGenerator/issues
Priority place for ideas and general questions: https://github.com/HavenDV/DependencyPropertyGenerator/discussions
I also have a Discord support channel:
https://discord.gg/g8u2t9dKgE