Conversion with StrToDateTime and TFormatSettings does not work

Moore picture Moore · Nov 9, 2012 · Viewed 35k times · Source

This code should work in Delphi XE2, but it gives "not a valid date and time" error in StrtoDateTime conversion:

procedure TForm2.Button1Click(Sender: TObject);
var
  s: string;
  d: TDateTime;
  FmtStngs: TFormatSettings;
begin
    GetLocaleFormatSettings(GetThreadLocale, FmtStngs);
    FmtStngs.DateSeparator := #32;
    FmtStngs.ShortDateFormat := 'dd mmm yyyy';
    FmtStngs.TimeSeparator := ':';
    FmtStngs.LongTimeFormat := 'hh:nn';

    s := FormatDateTime('', Now, FmtStngs);
    d := StrToDateTime(s, FmtStngs);
end;

Any hints?

Answer

Sir Rufo picture Sir Rufo · Nov 9, 2012

If you want to convert some special DateTime-Formats you should better use VarToDateTime instead of StrToDateTime. Just have a look at the implementation of both and you will recognize, that StrToDateTime is somehow ... and VarToDateTime will ask the OS if it can't determine by itself.

This works with Delphi XE3 (but should also work with earlier versions):

procedure TForm2.Button1Click( Sender: TObject );
var
  s: string;
  d: TDateTime;
  FmtStngs: TFormatSettings;
begin
    GetLocaleFormatSettings( GetThreadLocale, FmtStngs );
    FmtStngs.DateSeparator := #32;
    FmtStngs.ShortDateFormat := 'dd mmm yyyy';
    FmtStngs.TimeSeparator := ':';
    FmtStngs.LongTimeFormat := 'hh:nn';

    s := FormatDateTime( '', Now, FmtStngs );
    d := VarToDateTime( s );
end;