How to get the year when bolding month days in a TMonthCalendar?

Question

I have a log that use the Calendar and I want to bold the days that have recorded info. I have them in an 3D array TDiaryLog = array[1900..2399] of array[1..12] of array[1..31] of POneDay;. But in the OnGetMonthInfo, when I must build the list with the bold days, it gives me only the Month, and not the Year. How should I know for what month I must pass the day if I don't have the year ? When December is displayed as the current month in the Calendar, there are a few days shown from the January next year !

procedure TMainForm.CalendarGetMonthInfo(Sender: TObject; Month: Cardinal;
  var MonthBoldInfo: Cardinal);
begin
end;

Answer 1

I made a new component where I intercepted the MCN_GETDAYSTATE message and I extracted the year too from the message info... It was there all the time, but Delphi decided that year is not useful.

  TOnGetMonthInfoExEvent = procedure(Sender: TObject; Year, Month: Word;
    var MonthBoldInfo: LongWord) of object;

  TNewMonthCalendar = class(TMonthCalendar)
  private
    FOnGetMonthInfoEx: TOnGetMonthInfoExEvent;
    procedure CNNotify(var Msg: TWMNotifyMC); message CN_NOTIFY;
  published
    property OnGetMonthInfoEx: TOnGetMonthInfoExEvent read FOnGetMonthInfoEx write FOnGetMonthInfoEx;
  end;

procedure TNewMonthCalendar.CNNotify(var Msg: TWMNotifyMC);
var
  I: Integer;
  Month, Year: Word;
  DS: PNMDayState;
  CurState: PMonthDayState;
begin
 if (Msg.NMHdr.code = MCN_GETDAYSTATE) and Assigned(FOnGetMonthInfoEx) then begin
  DS:= Msg.NMDayState;
  FillChar(DS.prgDayState^, DS.cDayState * SizeOf(TMonthDayState), 0);
  CurState:= DS.prgDayState;
  for I:= 0 to DS.cDayState - 1 do begin
   Year:= DS.stStart.wYear;
   Month:= DS.stStart.wMonth + I;
   if Month > 12 then begin Inc(Year); Dec(Month, 12); end;
   FOnGetMonthInfoEx(Self, Year, Month, CurState^);
   Inc(CurState);
  end;
 end
 else inherited;
end;

BONUS

And, as a bonus, you need this to update the changes you made to the bold info of the current month view... because it doesn't work with Invalidate.

procedure TNewMonthCalendar.RefreshDayState;
var N: Cardinal;
    Range: array[0..1] of TSystemTime;
    Year, Month: Word;
    States: array of TMonthDayState;
    I: Integer;
begin
 if not Assigned(FOnGetMonthInfoEx) then Exit;
 N:= SendMessage(Handle, MCM_GETMONTHRANGE, GMR_DAYSTATE, LPARAM(@Range));
 Year:= Range[0].wYear;
 Month:= Range[0].wMonth;
 SetLength(States, N);
 FillChar(States[0], N * SizeOf(TMonthDayState), 0);
 for I:= 0 to N-1 do begin
  FOnGetMonthInfoEx(Self, Year, Month, States[I]);
  Inc(Month);
  if Month > 12 then
   begin Dec(Month, 12); Inc(Year); end;
 end;
 SendMessage(Handle, MCM_SETDAYSTATE, N, LPARAM(@States[0]));
end;