void setOrder(string fieldlist, EncodingInfo e);

Function setOrder() sets order of records by some field or list of fields.
The function does not change a file, it re-orders records in a memory.
One function accepts a string with fields delimited by comma, another function accepts an array.
To return the original order of records - call unserOrder().
function descendingMode() set either ascending or descending order.

void setOrder(byte[] fieldlist);
void setOrderA(string[] fields);
void unsetOrder();
void descendingMode(bool descending);

    // your code
    dbf.setOrder("FIRSTNAME,LASTNAME", e);
    dbf.setOrderA( {"FIRSTNAME", "LASTNAME"} );
    // your code