Protected Friend MustOverride Function CreateInstance ( _
    type As Type, _
    culture As CultureInfo _
) As Object

Dim type As Type
Dim culture As CultureInfo
Dim returnValue As Object

returnValue = Me.CreateInstance(type, _
    culture)

protected internal abstract Object CreateInstance(
    Type type,
    CultureInfo culture
)

protected public:
virtual Object^ CreateInstance(
    Type^ type, 
    CultureInfo^ culture
) abstract

protected internal abstract function CreateInstance(
    type : Type, 
    culture : CultureInfo
) : Object

You cannot use methods in XAML.