【忘備録】WPFでMVVMやるときのサンプルテンプレート集

WPFアプリをMVVMで開発する際によく使うコードのテンプレートをここに残しておく。

コマンドクラス

RelayCommand.cs

using System;
using System.Windows.Input;

namespace ListViewLib
{
    public class RelayCommand : ICommand
    {
        private readonly Action<object> _execute;
        private readonly Predicate<object> _canExecute;

        public RelayCommand(Action<object> execute, Predicate<object> canExecute = null)
        {
            _execute = execute;
            _canExecute = canExecute;
        }

        public bool CanExecute(object parameter) => _canExecute?.Invoke(parameter) ?? true;
        public void Execute(object parameter) => _execute(parameter);

        public event EventHandler CanExecuteChanged
        {
            add => CommandManager.RequerySuggested += value;
            remove => CommandManager.RequerySuggested -= value;
        }
    }
}

INotifyPropertyChangedの実装

sample.cs

        public event PropertyChangedEventHandler PropertyChanged;
        protected void OnPropertyChanged(string propertyName) =>
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));

VMのプロパティ

sampleViewModel.cs

        private string _property;
        public string Property
        {
            get => _property;
            set
            {
                if (_property == value) return;
                _property = value;
                OnPropertyChanged(nameof(Property));
            }
        }

DependancyProperty

SampleDependancyProperty.cs

        static public DependencyProperty SampleProperty =
            DependencyProperty.Register(
            nameof(Sample),
            typeof(string),
            typeof(SampleDependancyProperty),
            new PropertyMetadata(null, SamplePropertyChanged));

        public string Sample
        {
            get => (string)GetValue(SampleProperty);
            set => SetValue(SampleProperty, value);
        }
        private static void SamplePropertyChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
        {
            Trace.WriteLine($"Sampleが変わりました。NewValue={e.NewValue}");
        }