How to convert WMI DateTime to standard DateTime?

Question

I'm trying to read the install date from WMI (Win32_OperatingSystem.InstallDate). The return value looks like this: 20091020221246.000000+180. How can I get a valid Date?

Answer 1

Instead of parsing and extracting the values manually (how the accepted answer suggest), you can use the WbemScripting.SWbemDateTime object.

check this sample

function  WmiDateToTDatetime(vDate : OleVariant) : TDateTime;
var
  FWbemDateObj  : OleVariant;
begin;
  FWbemDateObj  := CreateOleObject('WbemScripting.SWbemDateTime');
  FWbemDateObj.Value:=vDate;
  Result:=FWbemDateObj.GetVarDate;
end;

For more info about this topic you can read this artile WMI Tasks using Delphi – Dates and Times

Answer 2

MagWMI from Magenta Systems contains MagWmiDate2DT() that does this.

http://www.magsys.co.uk/delphi/magwmi.asp

Answer 3

System.Management.ManagementDateTimeConverter.ToDateTime

Answer 4

WbemScripting.SWbemDateTime does not always work. Better way:

function WmiDate2DT (S: string; var UtcOffset: integer): TDateTime ;
// yyyymmddhhnnss.zzzzzzsUUU  +60 means 60 mins of UTC time
// 20030709091030.686000+060
// 1234567890123456789012345
var
    yy, mm, dd, hh, nn, ss, zz: integer ;
    timeDT: TDateTime ;

    function GetNum (offset, len: integer): integer ;
    var
        E: Integer;
    begin
        Val (copy (S, offset, len), result, E) ;
    end ;

begin
    result := 0 ;
    UtcOffset := 0 ;
    if length (S) <> 25 then exit ;   // fixed length
    yy := GetNum (1, 4) ;
    mm := GetNum (5, 2) ;
    if (mm = 0) or (mm > 12) then exit ;
    dd := GetNum (7, 2) ;
    if (dd = 0) or (dd > 31) then exit ;
    if NOT TryEncodeDate (yy, mm, dd, result) then     // D6 and later
    begin
        result := -1 ;
        exit ;
    end ;
    hh := GetNum (9, 2) ;
    nn := GetNum (11, 2) ;
    ss := GetNum (13, 2) ;
    zz := 0 ;
    if Length (S) >= 18 then zz := GetNum (16, 3) ;
    if NOT TryEncodeTime (hh, nn, ss, zz, timeDT) then exit ;   // D6 and later
    result := result + timeDT ;
    UtcOffset := GetNum (22, 4) ; // including sign
end ;

function VarDateToDateTime(const V: OleVariant): TDateTime;
var
    rawdate: string ;
    utcoffset: integer ;
begin
  Result:=0;
  if VarIsNull(V) then exit;
  Dt.Value := V;
  try
  Result:=Dt.GetVarDate;
  except
    rawdate:=V;
    result := WmiDate2DT (rawdate, utcoffset);
  end;
end;

Answer 5

maybe this helps: http://technet.microsoft.com/en-us/library/ee156576.aspx