I have to know how to copy data from TMemoField to TMemo. I can of
  course use TDBMemo to show TMemofield's data, but I have to use
  TMemo in my application. I have tried to use method GetData, but
  there comes an error message 'Operation not accessible'. Any idea
  of how to do this thing ?

  Thanks in advance,

  Jukka Valta, va...@messi.uku.fi

This works for me:

  try
    list:=TStringList.Create;
    list.Assign(TMemoField(Field));
   { do what you want with the TStringList "list" here }
  finally
    list.Free;
  end;