WPF MVVM: How to close a window

Question

I have a Button that closes my window when it\'s clicked:

Ok

Answer 1

I also had to deal with this problem, so here my solution. It works great for me.

1. Create class DelegateCommand

    public class DelegateCommand : ICommand
{
    private Predicate _canExecuteMethod;
    private readonly Action _executeMethod;
    public event EventHandler CanExecuteChanged;

    public DelegateCommand(Action executeMethod) : this(executeMethod, null)
    {
    }
    public DelegateCommand(Action executeMethod, Predicate canExecuteMethod)
    {
        this._canExecuteMethod = canExecuteMethod;
        this._executeMethod = executeMethod ?? throw new ArgumentNullException(nameof(executeMethod), "Command is not specified."); 
    }


    public void RaiseCanExecuteChanged()
    {
        if (this.CanExecuteChanged != null)
            CanExecuteChanged(this, null);
    }
    public bool CanExecute(object parameter)
    {
        return _canExecuteMethod == null || _canExecuteMethod((T)parameter) == true;
    }

    public void Execute(object parameter)
    {
        _executeMethod((T)parameter);
    }
}

2. Define your command

        public DelegateCommand CloseWindowCommand { get; private set; }


    public MyViewModel()//ctor of your viewmodel
    {
        //do something

        CloseWindowCommand = new DelegateCommand(CloseWindow);


    }
        public void CloseWindow(Window win) // this method is also in your viewmodel
    {
        //do something
        win?.Close();
    }

3. Bind your command in the view

public MyView(Window win) //ctor of your view, window as parameter
    {
        InitializeComponent();
        MyButton.CommandParameter = win;
        MyButton.Command = ((MyViewModel)this.DataContext).CloseWindowCommand;
    }

4. And now the window

  Window win = new Window()
        {
            Title = "My Window",
            Height = 800,
            Width = 800,
            WindowStartupLocation = WindowStartupLocation.CenterScreen,

        };
        win.Content = new MyView(win);
        win.ShowDialog();

so thats it, you can also bind the command in the xaml file and find the window with FindAncestor and bind it to the command parameter.