xaml-csharp-development-skill-for-avalonia

WPF CommandManager, RoutedCommand, and CommandBinding Migration to Avalonia

Table of Contents

1. Scope and APIs
2. Command Infrastructure Mapping
3. Conversion Example
4. Avalonia C# Equivalent
5. Troubleshooting

Scope and APIs

Primary WPF APIs:

• RoutedCommand, RoutedUICommand
• CommandBinding
• CommandManager.RequerySuggested / InvalidateRequerySuggested()

Primary Avalonia APIs:

• ICommand command sources (Button, MenuItem, ToggleButton)
• KeyBinding and HotKey for keyboard activation
• explicit command-state invalidation by raising CanExecuteChanged

Avalonia 11.3.12 does not provide WPF CommandManager/CommandBinding routing primitives.

Command Infrastructure Mapping

WPF	Avalonia
RoutedCommand + CommandBinding	ICommand on control + view-model command handlers
CommandManager.RequerySuggested	explicit CanExecuteChanged raise from command implementation
Window.InputBindings	KeyBindings on Window/UserControl

Conversion Example

WPF XAML:

<Window.CommandBindings>
  <CommandBinding Command="{x:Static ApplicationCommands.Save}"
                  Executed="SaveExecuted"
                  CanExecute="SaveCanExecute" />
</Window.CommandBindings>

<Window.InputBindings>
  <KeyBinding Command="{x:Static ApplicationCommands.Save}" Gesture="Ctrl+S" />
</Window.InputBindings>

Avalonia XAML:

<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:vm="using:MyApp.ViewModels"
             x:DataType="vm:EditorViewModel">
  <UserControl.KeyBindings>
    <KeyBinding Gesture="Ctrl+S" Command="{CompiledBinding SaveCommand}" />
  </UserControl.KeyBindings>

  <StackPanel Spacing="8">
    <Button Content="Save"
            Command="{CompiledBinding SaveCommand}" />
    <TextBlock Text="{CompiledBinding SaveStatus}" />
  </StackPanel>
</UserControl>

Avalonia C# Equivalent

using System;
using System.Windows.Input;
using Avalonia.Controls;
using Avalonia.Input;

public sealed class RelayCommand : ICommand
{
    private readonly Action _execute;
    private readonly Func<bool> _canExecute;

    public RelayCommand(Action execute, Func<bool> canExecute)
    {
        _execute = execute;
        _canExecute = canExecute;
    }

    public event EventHandler? CanExecuteChanged;

    public bool CanExecute(object? parameter) => _canExecute();

    public void Execute(object? parameter) => _execute();

    public void RaiseCanExecuteChanged() => CanExecuteChanged?.Invoke(this, EventArgs.Empty);
}

var saveCommand = new RelayCommand(
    execute: () => viewModel.Save(),
    canExecute: () => viewModel.CanSave);

var root = new UserControl();
root.KeyBindings.Add(new KeyBinding
{
    Gesture = KeyGesture.Parse("Ctrl+S"),
    Command = saveCommand
});

// Replace CommandManager.InvalidateRequerySuggested():
viewModel.CanSave = false;
saveCommand.RaiseCanExecuteChanged();

Troubleshooting

1. CanExecute does not refresh automatically after state changes.
   • Raise CanExecuteChanged explicitly when relevant state changes.
2. Shortcut displays in menu but command does not run.
   • Add KeyBinding/HotKey; gesture text alone is only visual metadata.
3. Migrated command logic is too coupled to views.
   • Move command state and execution logic into view models/services.

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