How to access class member variable inside the Eventhandler method in C#

Question

I am writing RFID reader application using the Hongkong RFID reader devices.

Vendor provided the Dll for to communicate (Socket communication) with their device and send the RFID tag information back to the application through Eventhandler.

and then, I need to store the same RFIDTags information into the DB for reporting purpose.

But the blocking point here is I dont know how to access the class member vars inside the EventHandler.

 Class HKRFID
        {
           private HKRFID.Active.HKRAREM[] mHKRFIDClass;

           private Init()
           {        

             mHKRFIDClass = new HKRFID.Active.HKRAREM[5];   //total rfid reader     count is 5.
             mHKRFIDClass[i] = new HKRFID.Active.HKRAREM(_sProcDetails[i].IpAddress, HKRFID.Active.HKRAREM.ConnectionType.TCP);
             mHKRFIDClass[i].GetLibVersion();
             mHKRFIDClass[i].Connect();                             
             mHKRFIDClass[i].StartTagInventory();
          // Register receive tags event, reader_BulkReadReturn
          mHKRFIDClass[i].TagReturn += new EventHandler<HKRFID.Active.HKRAREM.TagReturnEventArgs>(reader_BulkReadReturn);
            }

        void reader_BulkReadReturn(object sender,HKRFID.Active.HKRAREM.TagReturnEventArgs e){                       
                        string tag_id = HKRFID.Utility.HexTools.ByteArrayToHexString(e.return_tag.tag_id);

              string tagID = tag_id.Replace("-", "");
              string sTagID = tagID.Trim().Substring(0, tagID.Length - 2);

//Here I need to know which RFID reader device reads this tag information.
e.G) IP address of this RFID reader device.

//FYI, I have all reader information in the mHKRFIDClass[] object.

             }
         }

Since the Eventhandler method is from Vendor Dll , I could not modify that.

So Please advise me how to match the received RFID tag information with the corresponding reader OR advise me better code design pattern than the above code.

Thanks in advance.