voilà mon code:
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim N As New DirectoryInfo("c:\users\ordis\documents\test")
Dim NR As DirectoryInfo = N.CreateSubdirectory("essaie")
Dim chemr As New DirectoryInfo("c:\users\ordis\documents\test2")
Dim extention As String = ("_pdf")
extention = Path.GetFileNameWithoutExtension("_pdf")
For Each extention In Directory.GetFiles("c:\users\ordis\documents\test2", extention, System.IO.SearchOption.AllDirectories)
file.Copy("c:\users\ordis\documents\test2", "c:\users\ordis\documents\test")
My.Computer.FileSystem.RenameFile("c:\users\ordis\documents\essaie\_pdf", dirrep & ".pdf")
Next
End Sub
Ce n'est peut être pas selon les normes mais ça fonctionne.
merci pour l'aide encore!