VarPtr in .net

Hello. I have a Pic conected by usb to a PC and I need to make a program in .net. The code in VB6 is something like that

MPUSBRead(myOutPipe, VarPtr(SendData(0)), 1, recievedlength, 100)

I need a pointer to a array of long as secont parameter, but I don't know how to replace the VarPtr in .net

I'm not properly a programmer so please post any kind of help.

vb doesn't have pointers. look into UNSAFE code samples