CanExecute未调用

Question

我有一个程序集，我在类中定义Application wide命令：

public class CtrlCommands
{
    public static readonly RoutedUICommand CtrlAddToFavourites = new RoutedUICommand("CtrlAddToFavourites", "CtrlAddToFavourites", typeof(CtrlCommands));
    public static readonly RoutedUICommand CtrlRemoveFromFavourites = new RoutedUICommand("CtrlRemoveFromFavourites", "CtrlRemoveFromFavourites", typeof(CtrlCommands));
    public static readonly RoutedUICommand CtrlNew = new RoutedUICommand("CtrlNew", "CtrlNew", typeof(CtrlCommands));
    public static readonly RoutedUICommand CtrlDelete = new RoutedUICommand("CtrlDelete", "CtrlDelete", typeof(CtrlCommands));
    public static readonly RoutedUICommand CtrlSearch = new RoutedUICommand("CtrlSearch", "CtrlSearch", typeof(CtrlCommands));
}

在我的示例中，我在代码中生成自定义控件（Control派生自按钮）并分配命令（CtrlRibbonItem extends Button）：

mainPage.CtrlRibbonItems.Add(new CtrlRibbonItem { CtrlIcon = "file", Content = "Neu", Command = CtrlCommands.CtrlNew});

功能区项目始终处于非活动状态，并且永远不会调用canExecute处理程序。

在应用程序本身中，命令就像这样连接：

<mvvm:CtrlBaseUserControl.CommandBindings>
    <CommandBinding x:Name="CtrlNewCommandBinding"
                    Command="commands:CtrlCommands.CtrlNew"
                    CanExecute="CtrlNewCommandBinding_OnCanExecute"
                    Executed="CtrlNewCommandBinding_OnExecuted"/>
</mvvm:CtrlBaseUserControl.CommandBindings>

当我使用普通的WPF按钮时，一切正常......

更新 问题是在UserControl.CommandBindings中定义了命令绑定，而CtrlRibbonItem放在UserControl之外（功能区栏是窗口的一部分，而不是用户控件）