WPF中MVVM使用总结

背景：PropertyChanged和Command总是没有记住怎么写

PropertyChanged：

public event PropertyChangedEventHandler? PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
    PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}

RelayCommand：

public class RelayCommand : ICommand
{
    private readonly Action