using System.Windows; using WPF_13_INotifyPropertyChanged.Command; namespace WPF_13_INotifyPropertyChanged.ViewModels; public class MainWindowViewModel : ViewModelBase { private string? _content; private string? _title; public MainWindowViewModel() { ShowCommand = new ShowCommand(Show); } public string? Title { get => _title; set { _title = value; OnPropertyChanged(); } } public string? Content { get => _content; set { _content = value; OnPropertyChanged(); } } public ShowCommand ShowCommand { get; set; } private void Show() { Content = "Hello World"; Title = "Hello World---Title"; MessageBox.Show($"👼👼👼:{Content}"); } }