How do I get the names of the columns returned by a WbemScripting query?

I have the following procedure to run a WMI query, and it works perfectly well.

procedure TFormMain.GetWMIOSInfo(const RemoteMachine, Username, Password: string);
var
  FSWbemLocator: OLEVariant;
  FWMIService: OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject: OLEVariant;
  oEnum: IEnumvariant;
  iValue: LongWord;
begin;
  try
    FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
    FWMIService := FSWbemLocator.ConnectServer(RemoteMachine, 'root\CIMV2', Username, Password);
    FWbemObjectSet := FWMIService.ExecQuery(
        'select screenwidth, screenheight, status from Win32_DesktopMonitor','WQL', 0);
    try
      oEnum := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
      while oEnum.Next(1, FWbemObject, iValue) = 0 do
        begin
          Listbox1.Items.Add(
            VarToStr(FWbemObject.availability) + ', ' + 
            VarToStr(FWbemObject.screenwidth)  + ', ' +
            VarToStr(FWbemObject.screenheight));

   开发者_JS百科       FWbemObject := Unassigned;
        end;

    finally
      FWbemObjectSet := Unassigned;
    end;

  Except on E: Exception do
    Raise;
  end;
end;

I would like to alter the query to return all the fields like select * from Win32_DesktopMonitor. My problem is that I do not know how to determine the names of the columns that are returned by the query in FWbemObject. ie. I'd like to enumerate the columns in the FWbemObject.

Listbox1.Items.Add(
  VarToStr(FWbemObject.<?>) + ', ' + 
  VarToStr(FWbemObject.<?>)  + ', ' +
  ....
  VarToStr(FWbemObject.<?>));

Pieter you must use the SWbemObject.Properties_ Property of the SWbemObject Object.

check this sample.

program GetWMI_Info;

{$APPTYPE CONSOLE}

uses
  SysUtils,
  ActiveX,
  ComObj,
  Variants;


procedure  GetWin32_DesktopMonitorInfo;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;

  FProperties   : OLEVariant;
  oEnumProp     : IEnumvariant;
  iValueProp    : LongWord;
  FPropObj      : OLEVariant;
begin;
  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');
  FWbemObjectSet:= FWMIService.ExecQuery('SELECT * FROM Win32_DesktopMonitor','WQL',0);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  if oEnum.Next(1, FWbemObject, iValue) = 0 then
  begin

    FProperties   := FWbemObject.Properties_;
    oEnumProp     := IUnknown(FProperties._NewEnum) as IEnumVariant;
    while oEnumProp.Next(1, FPropObj, iValueProp) = 0 do
    begin
       Writeln(FPropObj.Name);
       FPropObj:=Unassigned; //prevent memory leak
    end;

    FWbemObject:=Unassigned;//prevent memory leak
  end;
end;


begin
 try
    CoInitialize(nil);
    try
      GetWin32_DesktopMonitorInfo;
      Readln;
    finally
    CoUninitialize;
    end;
 except
    on E:Exception do
    begin
        Writeln(E.Classname, ':', E.Message);
        Readln;
    end;
  end;
end.

The SWbemObject interface exposes the Properties_ property which is a collection (so you can enumerate it probably in the same way as you enumerate the SWebmObjectSet interface returned by ExecQuery). The items of this collection are SWbemProperty interfaces which expose Name and Value properties.