ThreadPool and large processing of WorkItem

[Techno]

Been trying to implementing ThreadPool over a large and variable amount of data like the following:

public sub ProcessWorkItem(byval state as object)

   Dim originalState as CustomStateInfo = CType(state, CustomStateInfo)

   'Do stuff

   originalState.ManualResetEventInstance.Set()

   
end sub

'
'

public sub DoWork()

   Dim myData as List(Of Something) = someSource.GetData() 'this can be 100, 4000 or more objects in the collection

   for each currentItem as Something in myData

      ThreadPool.QueueUserWorkItem(......)
      'somewhere here we do a WaitHandle.WaitAll(.....)
   next


end sub

This of course will bomb out if we have more than 64 items/threads being placed on the ThreadPool.

So, how would one process say x amount of items until there are no more items left to process? What is a better way of doing this?