WPF MVVM Patterns

Architecture

This project uses MVVM without a framework. Key base classes:

• •ViewModelBase (ViewModels/ViewModelBase.cs): INotifyPropertyChanged with SetProperty<T> helper
• •RelayCommand (ViewModels/RelayCommand.cs): ICommand implementation with Action/Func constructors

Adding a New View + ViewModel

1. •Create ViewModel in ViewModels/:

namespace WinContextMenuEditor.ViewModels;

public class FooViewModel : ViewModelBase
{
    private string _bar = string.Empty;
    public string Bar
    {
        get => _bar;
        set => SetProperty(ref _bar, value);
    }

    public ICommand DoSomethingCommand { get; }

    public FooViewModel()
    {
        DoSomethingCommand = new RelayCommand(OnDoSomething);
    }

    private void OnDoSomething() { /* ... */ }
}

1. •Create View XAML in Views/:

<UserControl x:Class="WinContextMenuEditor.Views.FooView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:vm="clr-namespace:WinContextMenuEditor.ViewModels">
    <UserControl.DataContext>
        <vm:FooViewModel/>
    </UserControl.DataContext>
    <!-- Use {Binding PropertyName} for data binding -->
</UserControl>

App-Level Resources

Registered in App.xaml:

• •{StaticResource BoolToVis} - BoolToVisibilityConverter (supports ConverterParameter=Invert)
• •{StaticResource InvertBoolConverter} - inverts bool values
• •Styles: ActionButton, ToolbarButton, FormLabel, FormTextBox, SearchTextBox, CategoryListBox, StatusBar
• •Strings: {DynamicResource KeyName} for i18n (see Resources/Strings.*.xaml)

i18n

• •Add entries to both Resources/Strings.en-US.xaml and Resources/Strings.ja-JP.xaml
• •Use {DynamicResource StringKey} in XAML (not StaticResource - dynamic enables runtime switching)

Dialog Pattern

For modal dialogs (see AddEditDialog as example):

1. •Create Window with DataContext bound to dialog ViewModel
2. •Set DialogResult in code-behind OK/Cancel click handlers
3. •Show with dialog.ShowDialog() == true

Conventions

• •Properties: use SetProperty(ref _field, value) for change notification
• •Commands: RelayCommand with Action or Action<object?> + optional Func<bool> canExecute
• •Converters: register in App.xaml ResourceDictionary
• •Keep code-behind minimal - logic in ViewModels, UI wiring only in code-behind