Protected Overloads Overridable Function FindElementUpFrom( _
   ByVal elt As FrameworkElement, _
   ByVal pred As Func(Of FrameworkElement,Nullable(Of Boolean)), _
   ByVal valid As Predicate(Of FrameworkElement) _
) As FrameworkElement

protected virtual FrameworkElement FindElementUpFrom( 
   FrameworkElement elt,
   Func<FrameworkElement,Nullable<bool>> pred,
   Predicate<FrameworkElement> valid
)

Parameters

elt

a FrameworkElement

pred

When this predicate and valid are both true, return that element, When this predicate is false, return null. Otherwise continue up the parent chain. Stop going up the visual parent chain when reaching the Northwoods.GoXam.Part.

valid

a predicate that must be true for an element for it to be returned by this method

Reference