OutWit.Common.MVVM.WPF 2.0.4

OutWit.Common.MVVM.WPF

WPF-specific MVVM components and utilities, including source generator for automatic DependencyProperty generation.

Features

• Source Generator for DependencyProperty: Automatically generate DependencyProperty from attributes
• WPF Commands: Command and DelegateCommand with CommandManager integration
• Binding Utilities: Helper methods for DependencyProperty registration
• Visual Tree Traversal: Extension methods for navigating WPF visual tree
• BindingProxy: Freezable binding proxy for DataContext access
• Legacy Support: Obsolete BindableAttribute for backward compatibility

Installation

dotnet add package OutWit.Common.MVVM.WPF

This automatically includes:

• OutWit.Common.MVVM (base cross-platform package)
• OutWit.Common.MVVM.WPF.Generator (source generator)
• OutWit.Common.Logging

Quick Start

Source Generator for DependencyProperty

The simplest way to create DependencyProperties:

using System.Windows.Controls;
using OutWit.Common.MVVM.WPF.Attributes;

namespace MyApp.Controls
{
    public partial class CustomButton : Button
    {
        [StyledProperty(DefaultValue = "Click Me")]
        public string Label { get; set; }

        [StyledProperty(AffectsMeasure = true)]
        public double IconSize { get; set; }
    }
}

Important: Mark your class as partial to allow source generator to add code.

The generator automatically creates:

// Generated code (you don't write this):
public static readonly DependencyProperty LabelProperty = ...;
public static readonly DependencyProperty IconSizeProperty = ...;

Advanced Property Generation

public partial class AdvancedControl : Control
{
    // Full explicit configuration
    [StyledProperty(
        DefaultValue = 100.0,
        AffectsMeasure = true,
        AffectsArrange = true,
        BindsTwoWayByDefault = true,
        OnChanged = nameof(OnWidthChanged))]
    public double CustomWidth { get; set; }

    private static void OnWidthChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var control = (AdvancedControl)d;
        // Handle change
    }
}

Convention-Based Callbacks

The generator automatically discovers callback methods by naming convention:

public partial class SmartControl : Control
{
    // No need to specify OnChanged - automatically discovered!
    [StyledProperty(DefaultValue = "Hello")]
    public string Title { get; set; }

    // Convention: On{PropertyName}Changed
    private static void OnTitleChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var control = (SmartControl)d;
        // Handle title change
    }

    // No need to specify Coerce - automatically discovered!
    [StyledProperty(DefaultValue = 100.0)]
    public double Width { get; set; }

    // Convention: {PropertyName}Coerce
    private static object WidthCoerce(DependencyObject d, object value)
    {
        return Math.Max(0, (double)value); // Ensure non-negative
    }
}

Benefits:

• ? Less boilerplate code
• ? Cleaner attributes
• ? Compile-time safety
• ? Override with explicit parameter when needed

Attached Properties

using OutWit.Common.MVVM.WPF.Attributes;

public static partial class MyAttachedProperties
{
    [AttachedProperty(DefaultValue = false)]
    public static bool IsHighlighted { get; set; }
}

// Usage in XAML:
// <Button local:MyAttachedProperties.IsHighlighted="True" />

WPF Commands

using OutWit.Common.MVVM.WPF.Commands;

public class MyViewModel
{
    public DelegateCommand SaveCommand { get; }

    public MyViewModel()
    {
        SaveCommand = new DelegateCommand(
            execute: _ => Save(),
            canExecute: _ => CanSave());
    }

    private void Save() { }
    private bool CanSave() => true;
}

Binding Utilities

Manual DependencyProperty registration (for when you can't use source generator):

using OutWit.Common.MVVM.WPF.Utils;

public class MyControl : Control
{
    public static readonly DependencyProperty TextProperty = 
        BindingUtils.Register<MyControl, string>(nameof(Text), "Default");

    public string Text
    {
        get => (string)GetValue(TextProperty);
        set => SetValue(TextProperty, value);
    }
}

Visual Tree Traversal

using OutWit.Common.MVVM.WPF.Utils;

// Find first child of specific type
var button = myPanel.FindFirstChildOf<Button>();

// Find with predicate
var redButton = myPanel.FindFirstChildOf<Button>(b => b.Background == Brushes.Red);

// Find all children
var allButtons = myPanel.FindAllChildrenOf<Button>();

// Find parent
var window = myButton.FindFirstParentOf<Window>();

BindingProxy for DataContext Access

<Window.Resources>
    <local:BindingProxy x:Key="Proxy" Data="{Binding}" />
</Window.Resources>

<DataGrid>
    <DataGrid.Columns>
        <DataGridTemplateColumn>
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    
                    <Button Command="{Binding Data.DeleteCommand, Source={StaticResource Proxy}}"
                            CommandParameter="{Binding}" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGrid.Columns>
    </DataGrid>
</Window.Resources>

StyledProperty Options

AttachedProperty Options

Migration from Old BindableAttribute

See Migration Guide for detailed instructions.

Quick summary:

1. Change [Bindable] to [StyledProperty]
2. Remove manual DependencyProperty declarations
3. Mark class as partial
4. Move options to attribute parameters

Legacy BindableAttribute (Deprecated)

The old BindableAttribute using AspectInjector is still available but deprecated:

[Obsolete("Use StyledPropertyAttribute instead")]
public class BindableAttribute : Attribute { }

Recommendation: Migrate to StyledPropertyAttribute for better IDE support and debugging.

Related Packages

• OutWit.Common.MVVM - Cross-platform base classes
• OutWit.Common.MVVM.Avalonia - Avalonia-specific implementation
• OutWit.Common.MVVM.Blazor - Blazor-specific implementation

License

Licensed under the Apache License, Version 2.0. See LICENSE.

Attribution (optional)

If you use OutWit.Common.MVVM.WPF in a product, a mention is appreciated (but not required), for example: "Powered by OutWit.Common.MVVM.WPF (https://ratner.io/)".

Trademark / Project name

"OutWit" and the OutWit logo are used to identify the official project by Dmitry Ratner.

You may:

• refer to the project name in a factual way (e.g., "built with OutWit.Common.MVVM.WPF");
• use the name to indicate compatibility (e.g., "OutWit.Common.MVVM.WPF-compatible").

You may not:

• use "OutWit.Common.MVVM.WPF" as the name of a fork or a derived product in a way that implies it is the official project;
• use the OutWit.Common.MVVM.WPF logo to promote forks or derived products without permission.