Copy files form pen-drive using OTG cable in Xamarin.Android, Not able to get Path

Question

I have tried everything but I am not able to get path of pendrive.

Here is my code :

var deviceList = mUsbManager.DeviceList;
IEnumerator<UsbDevice> deviceIterator = deviceList.Values.GetEnumerator();

while (deviceIterator.MoveNext())
{
    UsbDevice device = deviceIterator.Current;

    var mPermissionIntent = PendingIntent.GetBroadcast(this.ApplicationContext, 0, new Intent(ACTION_USB_PERMISSION), 0);

    UsbManager mUsbManager = (UsbManager)this.GetSystemService(Context.UsbService);
    mUsbManager.RequestPermission(device, mPermissionIntent);

    bool perm = mUsbManager.HasPermission(device);
    if (perm)
    {
        Java.Lang.Process process = Runtime.GetRuntime().Exec("ls /storage/7EFA-0EB6");
        BufferedReader buffer = new BufferedReader(new InputStreamReader(process.InputStream));

        string listOfFiles = "";
        string line;

        while ((line = buffer.ReadLine()) != null)
        {
            listOfFiles += line + "\n";
        }

        txt.Text += listOfFiles;

        var alrt = Toast.MakeText(this as Context, "\n" + process + "\n"+listOfFiles + "this Path ", ToastLength.Long);
        alrt.SetGravity(Android.Views.GravityFlags.Center, 0, 0);
        alrt.Show();
    }
}

Further I am not able to use mount points defined by manufacturers. like :

/storage/UsbDriveA  
/storage/USBstorage1
/storage/usbdisk    
/storage/usbotg     
/storage/UDiskA     
/storage/usb-storage
/storage/usbcard    
/storage/usb  

as you can see here I have write it hard-coded.

I am stuck in this since 2 weeks.

I just need to copy some Image file from pen-drive and store it in app data.