List of file using 'xp_cmdshell' path more then 128 char

I am trying to get list of file in a directory using sql server path having more then 128

character is not working.

DECLARE
@FilePath varchar(256)='D:\...',--replace your path with a length more then 128 char
@SourceFiles varchar(100)='Test123456789*.txt',
@Query varchar(1000)
If Object_Id('tempdb.dbo.#FirstTable') Is NULL
CREATE TABLE #FirstTable (Name varchar(256))
SET QUOTED_IDENTIFIER ON
SET @Query ='master.dbo.xp_cmdshell "dir '+ @FilePath + '\' + @SourceFiles +' /b"'
INSERT #FirstTable exec (@Query)
select * from #FirstTable
truncate table #FirstTable