Command binding does not work with a custom dependency property of ICommand type.

[dominkomin]

When I developed a custom user control that exposes a custom dependency property of ICommand type the exception is shown saying "there is no ID for given dependency property".

[DependencyProperty( Properties.OpenNotificationsCommand)]
public ICommand OpenNotificationsCommand { get; set; }

Maybe it is caused by the aspect [WpfControl( typeof( Properties ) )] which does not allow to expose commands ID's (Property of a command type is not accepted?).

Possible workaround solution is to use a control template and then template bindings. In that case exception is not thrown.

[Whathecode]

I don't fully understand the error. Could you paste the exact error message you get (the stack, e.g. as such)? Is it one I throw from the DependencyPropertyFactory, if so, which one exactly where? Or is it an error from WPF? When does it get thrown? Upon initialization? When trying to trigger the command?

[dominkomin]

Control code behind (non-framwork way is working):

[WpfControl( typeof( Properties ) )]
public partial class NotificationButton
{
    public enum Properties
    {
        SomeCommand
    }

    [DependencyProperty( Properties.SomeCommand )]
    public ICommand SomeCommand { get; set; }

    public static readonly DependencyProperty OpenNotificationsCommandProperty =    DependencyProperty.Register(
    "OpenNotificationsCommand", typeof( ICommand ),
    typeof( NotificationButton ) );
}

Usage in parent control (ActivityBar):

<common:NotificationButton
        OpenNotificationsCommand="{wtc:CommandBinding {x:Static barBinding:Commands.ShowNotifications}}"
        SomeCommand="{wtc:CommandBinding {x:Static barBinding:Commands.ShowNotifications}}"/>

XAML usage

<Button
    Cursor="Hand"
    Style="{Binding ButtonStyle}"
    Command="{Binding SomeCommand}">
    <Image Source="{Binding ButtonImage}" />
</Button>

Or 2nd option:

<Button
    Cursor="Hand"
    Style="{Binding ButtonStyle}"
    Command="{commandFactory:CommandBinding {x:Static common:NotificationButton.Properties.SomeCommand}}">
    <Image Source="{Binding ButtonImage}" />
</Button>

And finally inner exception thrown during compile for 1st option:
"No CommandFactory for ID type "Laevo.ViewModel.ActivityBar.Binding.Commands" in type "Laevo.View.Common.NotificationButton" found."

stack trace:
at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)

and for 2nd option:
"'Laevo.View.Common.NotificationButton.Properties.SomeCommand' StaticExtension value cannot be resolved to an enumeration, static field, or static property."

stack trace:
System.Windows.Markup.XamlParseException occurred
HResult=-2146233087
Message=Provide value on 'MS.Internal.Markup.StaticExtension' threw an exception.
Source=PresentationFramework
LineNumber=0
LinePosition=0
StackTrace:
at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
InnerException: System.ArgumentException
HResult=-2147024809
Message='Laevo.View.Common.NotificationButton.Properties.SomeCommand' StaticExtension value cannot be resolved to an enumeration, static field, or static property.
Source=System.Xaml
StackTrace:
at System.Windows.Markup.StaticExtension.ProvideValue(IServiceProvider serviceProvider)
at MS.Internal.Xaml.Runtime.ClrObjectRuntime.CallProvideValue(MarkupExtension me, IServiceProvider serviceProvider)
InnerException:

Took 1 hour to describe all that and my visual studio almost died from the amount of exception, hope it helps. :D