Binding BindableApplicationBarIconButton IsEnabled property to Relaycommand CanExecute Windows Phone 7.1 - silverlight

Question

I am using Phone7.Fx R1
The following works. The system does not react when a user presses the button. This means, than there is no reaction if Stop Game is pressed without a game has been started and vice versa.
However the button looks active. I am aware that I can bind the IsEnabled to a different property, but I would like it to bind to NewGameCanExecute and StopGameCanExecute. Is this possible?
Some XAML code:
<Preview:BindableApplicationBarIconButton Command="{Binding NewGame}" IconUri="/images/icons/appbar.add.rest.png" Text="New game" />
<Preview:BindableApplicationBarIconButton Command="{Binding StopGame}" IconUri="/images/icons/appbar.stop.rest.png" Text="Stop game" />
And the relay commands:
public RelayCommand NewGame { get; private set; }
public RelayCommand StopGame { get; private set; }
//Constructor
NewGame = new RelayCommand(NewGameExecute, NewGameCanExecute);
StopGame = new RelayCommand(StopGameExecute, StopGameCanExecute);
void NewGameExecute()
{
_gameStarted = true;
_gameControlModel.StartNewGame();
StopGame.RaiseCanExecuteChanged();
}
bool NewGameCanExecute()
{
return !_gameStarted;
}
void StopGameExecute()
{
_gameControlModel.StopGame();
_gameStarted = false;
NewGame.RaiseCanExecuteChanged();
}
bool StopGameCanExecute()
{
return _gameStarted;
}
Couple of questions and answers:
Q: Have you tried to set a breakpoint in the CanExecute functions to see if it gets called?
A: Yes. It does get called, but the icon is not grayed out, eventhough false is returned.
The Execute method is not executed, if the CanExecute method returns false. But I want the icon to be grayed out like a normal button.
SOLUTION
I spend some time and came up with a solution, which can be found here:
http://pastebin.com/MM75xACj

Answer 1

This is obviously a bug in whatever BindableApplicationBarIconButton implementation you're using.
Ask the author of it for help, or debug your 3rd party software yourself.

Answer 2

SOLUTION
I spend some time and came up with a solution and edited the applicationbariconbutton class.
namespace Phone7.Fx.Controls
{
public class BindableApplicationBarIconButton : FrameworkElement, IApplicationBarIconButton
{
public int Index { get; set; }
public static DependencyProperty CommandProperty = DependencyProperty.RegisterAttached("Command", typeof(ICommand), typeof(BindableApplicationBarIconButton), new PropertyMetadata(null, OnCommandPropertyChanged));
private static void OnCommandPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue != e.OldValue)
{
((BindableApplicationBarIconButton)d).Command = (ICommand)e.NewValue;
}
}
public ICommand Command
{
get { return (ICommand)GetValue(CommandProperty); }
set {
Command.CanExecuteChanged -= ValueOnCanExecuteChanged;
SetValue(CommandProperty, value);
Command.CanExecuteChanged += ValueOnCanExecuteChanged;
}
}
private void ValueOnCanExecuteChanged(object sender, EventArgs eventArgs)
{
ICommand commandSender = sender as ICommand;
if(commandSender != null)
{IsEnabled = commandSender.CanExecute(null);}
}
public static readonly DependencyProperty CommandParameterProperty =
DependencyProperty.RegisterAttached("CommandParameter", typeof(object), typeof(BindableApplicationBarIconButton), new PropertyMetadata(null, OnCommandParameterPropertyChanged));
private static void OnCommandParameterPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var invokeCommand = d as BindableApplicationBarIconButton;
if (invokeCommand != null)
{
invokeCommand.SetValue(CommandParameterProperty, e.NewValue);
}
}
public object CommandParameter
{
get { return GetValue(CommandParameterProperty); }
set
{
SetValue(CommandParameterProperty, value);
}
}
public static readonly DependencyProperty CommandParameterValueProperty =
DependencyProperty.RegisterAttached("CommandParameterValue", typeof(object), typeof(BindableApplicationBarIconButton), null);
public object CommandParameterValue
{
get
{
var returnValue = GetValue(CommandParameterValueProperty);
return returnValue;
}
set { SetValue(CommandParameterValueProperty, value); }
}
public static readonly DependencyProperty IsEnabledProperty =
DependencyProperty.RegisterAttached("IsEnabled", typeof(bool), typeof(BindableApplicationBarIconButton), new PropertyMetadata(true, OnEnabledChanged));
private static void OnEnabledChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue != e.OldValue)
{
((BindableApplicationBarIconButton)d).Button.IsEnabled = (bool)e.NewValue;
}
}
public static readonly DependencyProperty TextProperty =
DependencyProperty.RegisterAttached("Text", typeof(string), typeof(BindableApplicationBarIconButton), new PropertyMetadata(OnTextChanged));
public new static readonly DependencyProperty VisibilityProperty =
DependencyProperty.RegisterAttached("Visibility", typeof(Visibility), typeof(BindableApplicationBarIconButton), new PropertyMetadata(OnVisibilityChanged));
private static void OnVisibilityChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue != e.OldValue)
{
var button = ((BindableApplicationBarIconButton)d);
BindableApplicationBar bar = button.Parent as BindableApplicationBar;
bar.Invalidate();
}
}
public new Visibility Visibility
{
get { return (Visibility)GetValue(VisibilityProperty); }
set { SetValue(VisibilityProperty, value); }
}
private static void OnTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue != e.OldValue)
{
((BindableApplicationBarIconButton)d).Button.Text = e.NewValue.ToString();
}
}
public ApplicationBarIconButton Button { get; set; }
public BindableApplicationBarIconButton()
{
Button = new ApplicationBarIconButton();
Button.Text = "Text";
Button.Click += ApplicationBarIconButtonClick;
}
void ApplicationBarIconButtonClick(object sender, EventArgs e)
{
if (Command != null && CommandParameter != null)
Command.Execute(CommandParameter);
else if (Command != null)
Command.Execute(CommandParameterValue);
if (Click != null)
Click(this, e);
}
public bool IsEnabled
{
get { return (bool)GetValue(IsEnabledProperty); }
set { SetValue(IsEnabledProperty, value); }
}
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
public event EventHandler Click;
public Uri IconUri
{
get { return Button.IconUri; }
set { Button.IconUri = value; }
}
}