vb.net - Checking if string array and listbox have any similarities -

title says all, have been trying figure out how check if listbox , string array have entries equal , have been unsuccessful.

module module1     public detectedmd5 string() = {"944a1e869969dd8a4b64ca5e6ebc209a"} end module  public class form1  private sub button1_click(sender object, e eventargs) handles button1.click     dim procs() system.diagnostics.process = system.diagnostics.process.getprocesses     dim f string      each proc process in procs         f = getprocessfilename(proc)         if f.length > 0             listbox1.items.add(getmd5string(f))         end if     next      'here have been trying compare detectedmd5 string array listbox  end sub 

i did try doing such

            try             = + 1             listbox1.selectedindex =             dim detection string             each item string in detectedmd5                 detection = instr(listbox1.selecteditem, item)                 if detection > 0                     msgbox("detected")                 end if             next         catch             = -1             listbox1.items.clear()             exit         end try     loop 

but didn't work, , got

 exception thrown: 'system.argumentoutofrangeexception' in system.windows.forms.dll 

the reason gives invalidcastexception error because need cast listbox.items string.

dim intersection = detectedmd5.intersect(listbox1.items.cast(of string))