Public Shared Function GetValueSource ( _
    dependencyObject As DependencyObject, _
    dependencyProperty As DependencyProperty _
) As ValueSource

Dim dependencyObject As DependencyObject
Dim dependencyProperty As DependencyProperty
Dim returnValue As ValueSource

returnValue = DependencyPropertyHelper.GetValueSource(dependencyObject, _
    dependencyProperty)

public static ValueSource GetValueSource(
    DependencyObject dependencyObject,
    DependencyProperty dependencyProperty
)

public:
static ValueSource GetValueSource(
    DependencyObject^ dependencyObject, 
    DependencyProperty^ dependencyProperty
)

public static function GetValueSource(
    dependencyObject : DependencyObject, 
    dependencyProperty : DependencyProperty
) : ValueSource

You cannot use methods in XAML.