Sharepoit List getting Editor (Modified By) field value not working for shapoint groups.

Hi,

 I had an issue with getting value of SharePoint list.

object myObj = listItem[fieldName];
                    return ((myObj != null) ? myObj.ToString() : string.Empty);

//New Code
object myObj = listItem.ParentList.GetItemById(listItem.ID)[fieldName];
                    return ((myObj != null) ? myObj.ToString() : string.Empty);

The above old code working fine in normal.

we got requirement kind of creating new column, so whenever matter the old code failing whenever try getting value of Modified By ("Editor") value.

Any clues please.

I would like to know the reason behind the logic and any limitations for it?

Thanks & Regards,

Narayan Reddy