VISA ResourceManager Find Method

Hello ,

In my C# application to control an oscilloscope I am trying to find the list of devices connected so after I can connect using ResourceManager.Open(strDevice)

I found a syntax error in the rm.find

I would appreciate if somebody can help me to get the right syntax to find the list of devices and connect

Follows my code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NationalInstruments.Visa;
using Ivi.Visa;

namespace Oscilloscope_Test
{
class DeviceTest
{
public ResourceManager rm = new ResourceManager();
public MessageBasedSession visaSession;

public string[] ListDevices()
  {
     string[] device = rm.Find("(ASRL|GPIB|TCPIP|USB)?*"); // Error here wrong sintaxis

     return device;
   }
}

thanks