Ошибка nullreferenceexception при работе с папками - Visual Basic .NET

Формулировка задачи:

Public Class DIRfiles
    Dim dir As New IO.DirectoryInfo(), fi() As IO.FileInfo, i As Integer = 0, di() As IO.DirectoryInfo, files() As String
    Function Getfiles(patch As String) As String()
        dir = New IO.DirectoryInfo(patch)
        fi = dir.GetFiles
        For i = 0 To 2 fi.GetUpperBound(0)
            'MsgBox(fi(i).FullName)
            files(i) = fi(i).FullName
        Next ' тут почему то nullreferenceexception. Как, почему????
        Return files
    End Function
 
End Class

nullreferenceexception в next. VS 2017

Решение задачи: «Ошибка nullreferenceexception при работе с папками»

textual
                            Листинг программы 
                        

                            Public Class DIRfiles
    Shared Function Getfiles(path As String) As String()
        Return Directory.GetFiles(path)
    End Function
End Class
                        