if displayMode is showWithAncestorsAndDescendants - even if child records don't match filtering conditions. If displayMode is showWithAncestors show only those records that match filtering conditions and do not show child records(if any) that don't match filtering conditions

public System.Nullable<TreeGridFilteringDisplayMode> DisplayMode {get; set;}

'Declaration
 
Public Property DisplayMode As System.Nullable(Of TreeGridFilteringDisplayMode)