Delphi Conversion

Lucky me, now I get to convert a Delphi application to VB.Net.  My last project i had to convert a Java app to VB.Net.  Anyway I have most of the application converted however there are a few items that i have been unable to find the .Net equivalent.  Most are from the Delphi.Sysutils class.

TSearchRec
FindFirst/FindNext/FindClose
faAnyfile
Rightstr(right string)/ leftstr(left String)/ middlestr(middlestr)

Can anyone point me to the appropriate class in .Net

Any assistance would be welcomed.

Terry