using System.Windows; using GalaSoft.MvvmLight; using GalaSoft.MvvmLight.Command; namespace WPF_14_MvvmLight.ViewModels; public class MainViewModel : ViewModelBase { private string? _content; private string? _title; public MainViewModel() { // ShowCommand = new ShowCommand(Show); ShowCommand = new RelayCommand(Show); ShowArgCommand = new RelayCommand(ShowArg); } // public ShowCommand ShowCommand { get; set; } public RelayCommand ShowCommand { get; set; } public RelayCommand ShowArgCommand { get; set; } public string? Title { get => _title; set { _title = value; RaisePropertyChanged(); } } public string? Content { get => _content; set { _content = value; RaisePropertyChanged(); } } private void Show() { Title = "Hello World"; Content = "Hello World -- "; MessageBox.Show("Hello World -- "); } private void ShowArg(string arg) { Title = $"Hello World -- {arg}"; MessageBox.Show($"Hello World -- {arg}"); } }