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vxStrToDate

function vxStrToDate(const S: string): TDateTime;

Example​

procedure ScriptEvent(var Value: variant);
begin
  // For a host whose system short-date order is day/month/year:
  Value := vxStrToDate('31/12/2026');
end;

Usage​

vxStrToDate parses a date with Windows system-locale settings and raises when conversion fails.

Parameters

NameTypeDescription
Sstring, constDate text whose field order, separators, names and short-year rule are determined by Windows LOCALE_SYSTEM_DEFAULT.

Returns

The parsed date as a TDateTime with a zero time part. No timezone or UTC conversion is performed.

Behaviour

Normal Windows patterns use two or three date fields in month/day/year, day/month/year or year/month/day order. If the year field is omitted from a two-field input, the current local year is used. A two-digit year is expanded into the moving century window captured in the local settings record.

Errors

Invalid syntax, impossible dates, incomplete required fields or trailing content raises Velox EConvertError into the script.

Usage notes

Locale date parsing is suitable for values intentionally entered in the host's regional format. For machine interchange, prefer an explicit mask parser or an unambiguous normalised format, and use four-digit years.

Additional Technical Info​

vxStrToDate parses a date according to the Windows system locale and returns it as a Delphi TDateTime at midnight. It requires the complete input to conform to Delphi's locale-derived date scanner and raises on failure.

The example is locale-qualified and fictional. It is source-reviewed and not executed by the documentation workflow.

Implementation

The formats scripting import binds vxStrToDate to vxFormats.vxStrToDate. Each call creates TFormatSettings.Create(LOCALE_SYSTEM_DEFAULT) and invokes System.SysUtils.StrToDate(S, AFormatSettings). The installed Delphi 37.0 overload calls TryStrToDate, which scans from ShortDateFormat, requires full input consumption and raises EConvertError when scanning fails.

The terminal parses numeric fields or locale names implied by the short-date pattern, fills an omitted year from CurrentYear, applies TwoDigitYearCenturyWindow, defaults a day only if the locale pattern itself omits it, and validates the result with TryEncodeDate.

Edge cases and quirks

  • The date order and accepted separator come from the system locale, not the user profile of the interactive Designer or Velox Service account.
  • The result of text without a year changes when the current year changes. Two-digit year interpretation can also change as the current year moves relative to TwoDigitYearCenturyWindow.
  • A time suffix is not accepted by this date-only routine because the installed TryStrToDate wrapper requires the scanner position to pass the end of the string.
  • Locale short/long month or weekday names are accepted only when the system ShortDateFormat requests those name forms. If a weekday is present, the Delphi scanner verifies it against the encoded date.
  • Invalid leap days, reversed fields for the host locale, extra characters and wrong separators raise rather than being normalised.
  • A valid 30 December 1899 date returns numeric 0.0; zero is not an error sentinel for this raising routine.
  • Free Pascal's reference also describes one-number date input, but explicitly notes that behaviour is not supported in Delphi. Velox executes Delphi and does not inherit that extension.

Side effects

No application data is changed. Current date and Windows locale are observable inputs. The vxFormats unit has a separate one-time initialisation action that sets the initialising thread locale and refreshes Delphi globals.

Performance and concurrency

Scanning is linear in the short input and includes small locale-name searches. Explicit local settings isolate the call from Delphi global format changes; a later system-locale change can affect later calls.

Related entries

External references

Created 2026-07-15