Author: Jonas Bilinkevicius 

How to check if Active Desktop is enabled

Answer:

1   uses
2     ComObj, ShlObj, ActiveX;
3   
4   {Check if Active Desktop is enabled - Option 1}
5   
6   function IsActiveDeskTopOn: Boolean;
7   var
8     h: HWND;
9   begin
10    h := FindWindow('Progman', nil);
11    h := FindWindowEx(h, 0, 'SHELLDLL_DefView', nil);
12    h := FindWindowEx(h, 0, 'Internet Explorer_Server', nil);
13    Result := h <> 0;
14  end;
15  
16  {Check if Active Desktop is enabled - Option 2}
17  
18  function IsActiveDesktopEnable: Boolean;
19  const
20    CLSID_ActiveDesktop: TGUID = '{75048700-EF1F-11D0-9888-006097DEACF9}';
21  var
22    ActiveDesk: IActiveDesktop;
23    ComponentsOpt: TComponentsOpt;
24    hr: HRESULT;
25    dwReserved: DWORD;
26  begin
27    ZeroMemory(@ComponentsOpt, SizeOf(TComponentsOpt));
28    ComponentsOpt.dwSize := SizeOf(TComponentsOpt);
29    hr := CoCreateInstance(CLSID_ActiveDesktop, nil, CLSCTX_INPROC_SERVER,
30      CLSID_ActiveDesktop, ActiveDesk);
31    if SUCCEEDED(hr) then
32    begin
33      hr := ActiveDesk.GetDesktopItemOptions(ComponentsOpt, dwReserved);
34      {ActiveDesk._Release;}
35    end;
36    Result := ComponentsOpt.fActiveDesktop;
37  end;
38  
39  
40  //And here is how to activate the Active Desktop:
41  
42  
43  procedure TForm1.Button1Click(Sender: TObject);
44  const
45    CLSID_ActiveDesktop: TGUID = '{75048700-EF1F-11D0-9888-006097DEACF9}';
46  var
47    ActiveDesk: IActiveDesktop;
48    ComponentsOpt: TComponentsOpt;
49  begin
50    ActiveDesk := CreateComObject(CLSID_ActiveDesktop) as IActiveDesktop;
51    with ActiveDesk do
52    begin
53      ComponentsOpt.dwSize := SizeOf(ComponentsOpt);
54      GetDesktopItemOptions(ComponentsOpt, 0);
55      ComponentsOpt.fActiveDesktop := True;
56      SetDesktopItemOptions(ComponentsOpt, 0);
57      ApplyChanges(AD_APPLY_ALL);
58    end;
59  end;