I am currently using Florian Leitner's HID USB library in my VB.NET solution for communicating with a pin pad. As per his sample code, I set up an event handler to handle incoming responses from the device which are stored in an ArrayList called usbBuffer:

    Private Sub BufferEventHandler(ByVal sender As Object, ByVal e As System.EventArgs)

        If USBInterface.usbBuffer.Count > 0 Then

            While USBInterface.usbBuffer(0) Is Nothing

                SyncLock USBInterface.usbBuffer.SyncRoot

                    USBInterface.usbBuffer.RemoveAt(0)

                End SyncLock

            End While

            _receiveArray = CType(USBInterface.usbBuffer(0), Byte())

            _usbInterface.stopRead()

            SyncLock USBInterface.usbBuffer.SyncRoot

                USBInterface.usbBuffer.RemoveAt(0)

            End SyncLock

        End If

    End Sub

The problem is that the RemoveAt is not working, since the first element in the list remains there after the handler is done. Could someone please advise as to what I've done wrong, or perhaps use a different approach?