function readField(recno : Integer; field : Integer): Boolean;

Function readField() reads a single field to internal memory block.
After reading you can use functions getString(), getValue(), getDateTime(), getTicks(), getMemoBuf()

begin
    // your code
    for row := 0 to dbf.recCount()-1 do
    begin
        dbf.readField( row, field );
        // your code
    end;
end;