Public Shared Sub RegisterClassCommandBinding ( _
    type As Type, _
    commandBinding As CommandBinding _
)

Dim type As Type
Dim commandBinding As CommandBinding

CommandManager.RegisterClassCommandBinding(type, _
    commandBinding)

public static void RegisterClassCommandBinding(
    Type type,
    CommandBinding commandBinding
)

public:
static void RegisterClassCommandBinding(
    Type^ type, 
    CommandBinding^ commandBinding
)

public static function RegisterClassCommandBinding(
    type : Type, 
    commandBinding : CommandBinding
)

You cannot use methods in XAML.