public void AddRangeNoDuplicates( 
   T[] arr,
   System.int start,
   System.int count
)

Parameters

arr

start

count

Target Platforms: Windows 11, Windows 10, Windows 7, Windows Server 2019, Windows Server 2016, Windows Server 2012 R2, Windows Server 2012, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later)

Reference

NList<T> Class
NList<T> Members
Overload List