Storing the Internal Date

To store the date for the calendar, you need a private field to hold the date and a runtime-only property that provides access to that date.

Adding the internal date to the calendar requires three steps:

Declare a private field to hold the date:

Copy Code

type
  TSampleCalendar = class(TCustomGrid)
  private
    FDate: TDateTime;
  .
  .
  .

Copy Code

class PACKAGE TSampleCalendar : public TCustomGrid
{
public:
    __property TDateTime CalendarDate = {read=FDate, write=SetCalendarDate, nodefault};
    .
    .
    .
};

Copy Code

class PACKAGE TSampleCalendar : public TCustomGrid
{
private:
    TDateTime FDate; 
    .
    .
    .
};

Initialize the date field in the constructor:

Copy Code

constructor TSampleCalendar.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);         { this is already here }
  .                                  { other initializations here }
  .
  .
  FDate := Date;                    { get current date from RTL }
end;

Copy Code

__fastcall TSampleCalendar::TSampleCalendar(TComponent *Owner) : TCustomGrid(Owner)
{
  .
  .
  .
  FDate = FDate.CurrentDate();
}

Declare a runtime property to allow access to the encoded date. You'll need a method for setting the date, because setting the date requires updating the onscreen image of the control:

Copy Code

type
  TSampleCalendar = class(TCustomGrid)
  private
    procedure SetCalendarDate(Value: TDateTime);
  public
    property CalendarDate: TDateTime read FDate write SetCalendarDate;
  .
  .
  .
procedure TSampleCalendar.SetCalendarDate(Value: TDateTime);
begin
  FDate := Value;                { set new date value }
  Refresh;                       { update the onscreen image }
end;

Copy Code

class PACKAGE TSampleCalendar : public TCustomGrid
{
private:
    void __fastcall SetCalendarDate(TDateTime Value); 
    .
    .
    .
};

Copy Code

void __fastcall TSampleCalendar::SetCalendarDate(TDateTime Value)
{
  FDate = Value;                      // Set the new date value
  Refresh();                          // Update the onscreen image
}

What do you think about this topic? Send feedback!