how to add property to Window in xaml - wpf

Question

I'm learning MVVM by write an litle app with Login function. In View layer, I have a LoginWindow with some binding like this:
<TextBox x:Name="tbxUsername" Grid.Row="0" Grid.Column="1" Width="150" Height="22" Margin="15,10,5,10"
Text="{Binding Path=Username, UpdateSourceTrigger=PropertyChanged}" />
<PasswordBox View:PasswordHelper.Attach="True" View:PasswordHelper.Password="{Binding Path=Password, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"
x:Name="pwdPassword" Grid.Row="1" Grid.Column="1" Width="150" Height="22" Margin="15,10,5,10" />
The problem is i want to implement a binding like this:
<Window.Authenticated={Binding Path=Authenticated, UpdateSourceTrigger=PropertyChanged, Mode=OneWay, NotifyOnTargetUpdated=True} TargetUpdated="authenticated_TargetUpdated"/>
Authenticated is a bool value which will changed in my viewmodel.
Is there an way for me?
Edit for #lain:
Here my LoginWindow.xaml (style and layout removed).
<Window x:Class="ATCheck_View.LoginWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:View="clr-namespace:ATCheck_View"
xmlns:ViewModel="clr-namespace:ATCheck_ViewModel;assembly=ATCheck_ViewModel"
Title="Login"
WindowStartupLocation="CenterScreen"
ResizeMode="CanMinimize"
SizeToContent="WidthAndHeight"
>
<Window.DataContext>
<ViewModel:LoginViewModel />
</Window.DataContext>
<Grid>
<TextBox x:Name="tbxUsername" Grid.Row="0" Grid.Column="1"
Width="150" Height="22" Margin="15,10,5,10" Text="{Binding Path=Username, UpdateSourceTrigger=PropertyChanged, TargetNullValue='atcheck', NotifyOnTargetUpdated=True}"/>
<PasswordBox View:PasswordHelper.Attach="True" View:PasswordHelper.Password="{Binding Path=Password, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay, TargetNullValue='123456'}" x:Name="pwdPassword" Grid.Row="1" Grid.Column="1"
Width="150" Height="22" Margin="15,10,5,10" />
<Button x:Name="btnLogin" Width="65" Height="20" Margin="5,15,10,12"
Command="{Binding LoginCommand}"
CommandParameter="">
<TextBlock VerticalAlignment="Center">Login</TextBlock>
</Button>
<Button x:Name="btnCancel" Width="60" Height="20" Margin="5,15,5,12" Click="btnCancel_Click">
<TextBlock VerticalAlignment="Center">Cancel</TextBlock>
</Button>
</Grid>
</Window>
LoginViewModel:
public class LoginViewModel: ViewModelBase
{
private string _username;
private string _password;
private bool _authenticated = false;
public string Username
{
get
{
return _username;
}
set
{
_username = value;
RaisePropertyChangedEvent("Username");
}
}
public string Password
{
get
{
return _password;
}
set
{
_password = value;
RaisePropertyChangedEvent("Password");
}
}
public bool Authenticated
{
get
{
return _authenticated;
}
private set
{
_authenticated = value;
RaisePropertyChangedEvent("Authenticated");
}
}
public ICommand LoginCommand
{
get
{
return new RelayCommand<string>(Login);
}
}
private void Login(string p)
{
Authenticated = true;
Console.WriteLine("Infomation:");
Console.WriteLine(Authenticated);
Console.WriteLine(Username);
Console.WriteLine(Password);
}
}
ViewModelBase implement INotifyPropertyChanged and RelayCommand that I folow John Smith's article.
#nit: I tried as your lead, propdp, rebuild, and type Authenticated folow "Window" tag, but nothing happened when I press commbo Ctrl + Space.
What all i want to do is an messagebox that will show when Authenticated change from False to True:
private bool _authenticated = false;
public bool Authenticated
{
get
{
return _authenticated;
}
set
{
if (value == true)
{
MessageBox.Show("Logged!");
}
}
}
public LoginWindow()
{
InitializeComponent();
LoginViewModel myViewModel = (LoginViewModel)this.DataContext;
myViewModel.PropertyChanged += myViewModel_PropertyChanged;
}
void myViewModel_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
if (e.PropertyName == "Authenticated")
{
Authenticated = ((LoginViewModel)sender).Authenticated;
}
}

Answer 1

You will have to add DependencyProperty to your Window class like below:
public static readonly DependencyProperty AuthenticatedProperty =
DependencyProperty.Register( "Authenticated", typeof(bool),
typeof(YOURWINDOWCLASS), new FrameworkPropertyMetadata(false));
// .NET Property wrapper
public bool Authenticated
{
get { return (bool)GetValue(AuthenticatedProperty ); }
set { SetValue(AuthenticatedProperty , value); }
}
Then you can bind
<Window Authenticated={Binding Path=Authenticated, UpdateSourceTrigger=PropertyChanged, Mode=OneWay, NotifyOnTargetUpdated=True} TargetUpdated="authenticated_TargetUpdated"/>