This function tests whether a valid TDateTime value would be generated from the specified individual parts.

There are constraints as to the values that are accepted for the input parameters.

  • The year must be between 1 and 9999.

  • Valid month values are 1 through 12.

  • Valid day values are 1 through 28, 29, 30, or 31, depending on the month value. For example, the possible day values for month 2 (February) are 1 through 28 or 1 through 29, depending on whether or not the year value specifies a leap year.

  • Valid hour values are 0 through 24. If the specified hour is 24, the minute, second, and millisecond values should all be 0, and the resulting TDateTime value represents midnight at the end of the specified day and the beginning of the next day.

  • Valid minute values are 0 through 59.

  • Valid second values are 0 through 59.

  • Valid millisecond values are 0 through 999.

If the specified values are within range, the TryEncodeDateTime function returns a boolean value of True, and the encoded date/time value is available from the output parameter AValue.

Where the EncodeDateTime function will generate an error if any part fails, TryEncodeDateTime will not. If any of the specified values are not within range, TryEncodeDateTime returns a boolean value of False, and the output parameter AValue is set to zero. This will display as 30 Dec 1899.

Declaration: Function TryEncodeDateTime(const AYear, AMonth, ADay, AHour, AMinute, ASecond, AMilliSecond: Word; out AValue: TDateTime): Boolean;

For example.

procedure OnMapEvent(var Value:Variant);
var
lYear, lMonth, lDay, lHour, lMin, lSec, lMil : word;
lDate: TDateTime;
 
begin
//Test for valid creation of a date/time from its separate parts
Value := TryEncodeDateTime(lYear, lMonth, lDay, lHour, lMin, lSec, lMil, lDate);
 
end;

Please also refer to EncodeDateTime at EncodeDateTime and DecodeDateTime at DecodeDateTime.