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Date Selection

TTMSFNCCalendar supports single and multi-date selection, keyboard navigation, and programmatic range selection. The same API applies to TTMSFNCDatePicker, which displays the calendar in a dropdown.

Selecting dates

Select dates, set limits and navigatePascalC++
// --- Single date selection ---
TMSFNCCalendar1.SelectADate(Now + 2);   // select one date, deselects all others

// --- Multi-date selection (requires MultiSelect) ---
TMSFNCCalendar1.Interaction.MultiSelect := True;
TMSFNCCalendar1.SelectDate(Now - 3);                 // add a date to the selection
TMSFNCCalendar1.SelectDate(EncodeDate(2025, 12, 25));

// Range selection: select all dates from AStartDate to AEndDate (clears prior selection)
TMSFNCCalendar1.SelectMultiDates(Now - 10, Now + 5);

// --- Reading selected dates ---
var
  d: TDate;
begin
  d := TMSFNCCalendar1.SelectedDate;  // last / only selected date
  if TMSFNCCalendar1.SelectedDates.Count > 0 then
    d := TMSFNCCalendar1.SelectedDates.Items[0];
end;

// --- Deselecting ---
TMSFNCCalendar1.SelectedDates.UnselectAll;
TMSFNCCalendar1.SelectedDates.UnselectDate(Now);

// --- Date limits ---
TMSFNCCalendar1.MinDate := EncodeDate(2024, 1, 1);
TMSFNCCalendar1.MaxDate := EncodeDate(2026, 12, 31);

// --- Navigate the calendar view ---
TMSFNCCalendar1.Date  := EncodeDate(2025, 6, 1);  // jump to June 2025
TMSFNCCalendar1.Month := 12;
TMSFNCCalendar1.Year  := 2025;

// React to selection
procedure TForm1.TMSFNCCalendar1SelectDate(Sender: TObject; ADate: TDate);
begin
  ShowMessage(DateToStr(ADate) + ' selected');
end;

// --- Single date selection ---
void __fastcall TForm1::CalendarDateExamples()
{
  TMSFNCCalendar1->SelectADate(Now() + 2);   // select one date, deselects all others

  // --- Multi-date selection (requires MultiSelect) ---
  TMSFNCCalendar1->Interaction->MultiSelect = true;
  TMSFNCCalendar1->SelectDate(Now() - 3);                 // add a date to the selection
  TMSFNCCalendar1->SelectDate(EncodeDate(2025, 12, 25));

  // Range selection: select all dates from AStartDate to AEndDate (clears prior selection)
  TMSFNCCalendar1->SelectMultiDates(Now() - 10, Now() + 5);

  // --- Reading selected dates ---
  TDate d = TMSFNCCalendar1->SelectedDate();  // last / only selected date
  if (TMSFNCCalendar1->SelectedDates->Count > 0)
    d = TMSFNCCalendar1->SelectedDates->Items[0]->Date;

  // --- Deselecting ---
  TMSFNCCalendar1->SelectedDates->UnselectAll();
  TMSFNCCalendar1->SelectedDates->UnselectDate(Now());

  // --- Date limits ---
  TMSFNCCalendar1->MinDate = EncodeDate(2024, 1, 1);
  TMSFNCCalendar1->MaxDate = EncodeDate(2026, 12, 31);

  // --- Navigate the calendar view ---
  TMSFNCCalendar1->Date  = EncodeDate(2025, 6, 1);  // jump to June 2025
  TMSFNCCalendar1->Month = 12;
  TMSFNCCalendar1->Year  = 2025;
}

// React to selection
void __fastcall TForm1::TMSFNCCalendar1SelectDate(TObject *Sender, TDate ADate)
{
  ShowMessage(DateToStr(ADate) + " selected");
}
Multiple individual dates selected

SelectADate — replace selection

Pascal
TMSFNCCalendar1.SelectADate(Now + 2);

Selects one date and deselects everything else. Also moves the focused date to the selected date.

SelectDate — add to selection

Pascal
TMSFNCCalendar1.Interaction.MultiSelect := True;
TMSFNCCalendar1.SelectDate(Now - 3);
TMSFNCCalendar1.SelectDate(EncodeDate(2025, 12, 25));

Keeps existing selected dates and adds the new one. Requires MultiSelect = True for more than one date.

SelectMultiDates — range selection

Pascal
TMSFNCCalendar1.SelectMultiDates(Now - 10, Now + 5);

Selects all dates from AStartDate to AEndDate and clears any previous selection.

Range of dates selected

Reading selected dates

Pascal
var d: TDate;
begin
  d := TMSFNCCalendar1.SelectedDate;  // last/only selected date
  if TMSFNCCalendar1.SelectedDates.Count > 0 then
    d := TMSFNCCalendar1.SelectedDates.Items[0];
end;

Deselecting dates

Pascal
TMSFNCCalendar1.SelectedDates.UnselectAll;         // clear all
TMSFNCCalendar1.SelectedDates.UnselectDate(Now);   // clear one date
All dates deselected

Date limits

Pascal
TMSFNCCalendar1.MinDate := EncodeDate(2024, 1, 1);
TMSFNCCalendar1.MaxDate := EncodeDate(2026, 12, 31);

Dates outside the min/max range are disabled and cannot be selected.

Interaction options

Set on TTMSFNCCalendar.Interaction:

Property Description
MultiSelect Enable selecting more than one date.
KeyboardSupport Allow keyboard navigation of the focused date.
ReadOnlyMode Disable all user date selection.

Events

Reach for the selection events whenever something outside the calendar has to follow the selection — a detail panel, an agenda list, a Save command, or a persisted user preference. Read the selection from the after event (OnSelectDate / OnSelectMultiDate), where SelectedDates already reflects the change; OnBeforeSelectDate still sees the previous state.

Event Signature Fires
OnBeforeSelectDate (Sender: TObject; ADate: TDate) Once per date, before it is added to SelectedDates.
OnSelectDate (Sender: TObject; ADate: TDate) Once per date, after it has been added.
OnSelectMultiDate (Sender: TObject; AStartDate, AEndDate: TDate) Once for a whole range instead of once per day.
Track the selection through the calendar eventsPascalC++
procedure TForm1.FormCreate(Sender: TObject);
begin
  TMSFNCCalendar1.Interaction.MultiSelect := True;

  TMSFNCCalendar1.OnBeforeSelectDate := DoBeforeSelectDate;
  TMSFNCCalendar1.OnSelectDate       := DoSelectDate;
  TMSFNCCalendar1.OnSelectMultiDate  := DoSelectMultiDate;
end;

{ Fires once per date, just before it is added to SelectedDates. The handler has
  no cancel parameter, so use it to observe or prefetch only - block a date with
  MinDate / MaxDate or Interaction.ReadOnlyMode instead. }
procedure TForm1.DoBeforeSelectDate(Sender: TObject; ADate: TDate);
begin
  StatusLabel.Text := 'Loading agenda for ' + DateToStr(ADate);
end;

{ Fires after the date has been added. SelectedDates is already up to date here,
  so this is the right place to read the full selection. }
procedure TForm1.DoSelectDate(Sender: TObject; ADate: TDate);
begin
  StatusLabel.Text := Format('%s selected (%d day(s) in total)',
    [DateToStr(ADate), TMSFNCCalendar1.SelectedDates.Count]);
end;

{ Fires once for a range selection - either SelectMultiDates or a shift-click
  drag - instead of once per day. AStartDate and AEndDate are the range bounds. }
procedure TForm1.DoSelectMultiDate(Sender: TObject; AStartDate, AEndDate: TDate);
begin
  StatusLabel.Text := Format('Range %s - %s',
    [DateToStr(AStartDate), DateToStr(AEndDate)]);
  SaveDateRange(AStartDate, AEndDate);
end;

void __fastcall TForm1::FormCreate(TObject *Sender)
{
  TMSFNCCalendar1->Interaction->MultiSelect = true;

  TMSFNCCalendar1->OnBeforeSelectDate = DoBeforeSelectDate;
  TMSFNCCalendar1->OnSelectDate       = DoSelectDate;
  TMSFNCCalendar1->OnSelectMultiDate  = DoSelectMultiDate;
}

// Fires once per date, just before it is added to SelectedDates. The handler has
// no cancel parameter, so use it to observe or prefetch only - block a date with
// MinDate / MaxDate or Interaction.ReadOnlyMode instead.
void __fastcall TForm1::DoBeforeSelectDate(TObject *Sender, TDate ADate)
{
  StatusLabel->Text = "Loading agenda for " + DateToStr(ADate);
}

// Fires after the date has been added. SelectedDates is already up to date here,
// so this is the right place to read the full selection.
void __fastcall TForm1::DoSelectDate(TObject *Sender, TDate ADate)
{
  StatusLabel->Text = Format("%s selected (%d day(s) in total)",
    ARRAYOFCONST((DateToStr(ADate), TMSFNCCalendar1->SelectedDates->Count)));
}

// Fires once for a range selection - either SelectMultiDates or a shift-click
// drag - instead of once per day. AStartDate and AEndDate are the range bounds.
void __fastcall TForm1::DoSelectMultiDate(TObject *Sender, TDate AStartDate, TDate AEndDate)
{
  StatusLabel->Text = Format("Range %s - %s",
    ARRAYOFCONST((DateToStr(AStartDate), DateToStr(AEndDate))));
  SaveDateRange(AStartDate, AEndDate);
}

Note

OnBeforeSelectDate carries no cancel parameter, so it cannot veto a selection. Prevent a date from being selected with MinDate / MaxDate, or block selection entirely with Interaction.ReadOnlyMode.

See also