procedure RefreshDesktop;
{©Drkb v.3(2007): www.drkb.ru}
var
 c1 : cardinal;
begin
c1:=FindWindowEx(FindWindowEx(FindWindow('Progman','Program Manager'),,'SHELLDLL_DefView',''),0,'SysListView32','');
PostMessage(c1,WM_KEYDOWN,VK_F5,0);
PostMessage(c1,WM_KEYUP,VK_F5,1 shl 31);
end;

winexec(Pchar( 'rundll32 user,repaintscreen' ),sw_Show);

procedure TForm1.Button1Click(Sender: TObject);
begin
 SendMessage(FindWindow('Progman', 'Program Manager'),
  WM_COMMAND,
  $A065,
  0);
end;

uses
  ShlObj;
 procedure RefreshDesktop1;
 begin
  SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, nil, nil);
 end;

{

 Microsoft's Tweak UI has a feature 'rebuild icon cache now'.

 Windows then rebuilds its internal cache of icons.

 Unfortunately, there is no single API to do this.

}

 uses

  Registry;

 function RefreshScreenIcons : Boolean;

 const

  KEY_TYPE = HKEY_CURRENT_USER;

  KEY_NAME = 'Control Panel\Desktop\WindowMetrics';

  KEY_VALUE = 'Shell Icon Size';

 var

  Reg: TRegistry;

  strDataRet, strDataRet2: string;

 procedure BroadcastChanges;

 var

  success: DWORD;

 begin

  SendMessageTimeout(HWND_BROADCAST,

  WM_SETTINGCHANGE,

  SPI_SETNONCLIENTMETRICS,

  0,

  SMTO_ABORTIFHUNG,

  10000,

  success);

 end;



 begin

  Result := False;

  Reg := TRegistry.Create;

  try

  Reg.RootKey := KEY_TYPE;

  // 1. open HKEY_CURRENT_USER\Control Panel\Desktop\WindowMetrics

  if Reg.OpenKey(KEY_NAME, False) then

  begin

  // 2. Get the value for that key

  strDataRet := Reg.ReadString(KEY_VALUE);

  Reg.CloseKey;

  if strDataRet <> '' then

  begin

  // 3. Convert sDataRet to a number and subtract 1,

  // convert back to a string, and write it to the registry

  strDataRet2 := IntToStr(StrToInt(strDataRet) - 1);

  if Reg.OpenKey(KEY_NAME, False) then

  begin

  Reg.WriteString(KEY_VALUE, strDataRet2);

  Reg.CloseKey;

  // 4. because the registry was changed, broadcast

  // the fact passing SPI_SETNONCLIENTMETRICS,

  // with a timeout of 10000 milliseconds (10 seconds)

  BroadcastChanges;

  // 5. the desktop will have refreshed with the

  // new (shrunken) icon size. Now restore things

  // back to the correct settings by again writing

  // to the registry and posing another message.

  if Reg.OpenKey(KEY_NAME, False) then

  begin

  Reg.WriteString(KEY_VALUE, strDataRet);

  Reg.CloseKey;

  // 6. broadcast the change again

  BroadcastChanges;

  Result := True;

  end;

  end;

  end;

  end;

  finally

  Reg.Free;

  end;

 end;

 procedure TForm1.Button1Click(Sender: TObject);

 begin

  RefreshScreenIcons

 end;



 {

 The result is Window's erasing all its icons, and recalculating them

 based on the registry settings.

 This means if you have changed a DefaultIcon key within the registry for

 some application or file, Windows will display the new icon when the

 refresh is completed.

 Original source:

 <a href="http://www.mvps.org/vbnet/index.html?code/reg/screenrefresh.htm" title="www.mvps.org/vbnet/index.html?code/reg/screenrefresh.htm">www.mvps.org/vbnet/index.html?code/reg/screenrefresh.htm</a>

 Translated from VB by Thomas Stutz

}