Get users and groups from people/group column in sharepoint.

SPFieldUserValueCollection objUserFieldValueCol = new SPFieldUserValueCollection(properties.Web, item["users"].ToString());

for (int i = 0; i < objUserFieldValueCol.Count; i++)

{

SPFieldUserValue singlevalue = objUserFieldValueCol[i];

if (singlevalue.User == null)

{

//User

}

else

{

//All users from Group.

}

}