Can you send a signal to Windows Explorer to make it refresh the systray icons?

Question

This problem has been afflicting me for quite a while and it's been really annoying.

Every time I login after a reboot/power cycle the explorer takes some time to show up. I've taken the step of waiting for all the services to boot up and then I login, but it doesn't make any difference. The result is always the same: Some of the icons do not show up even if the applications have started.

I've dug a bit on the code that makes one application "stick" an icon in there, but is there an API call that one can perform so explorer re-reads all that icon info? Like invalidate or redraw or something of the sort?

---

Apparently, it looks like Jon was right and it's not possible to do it.

I've followed Bob Dizzle and Mark Ransom code and build this (Delphi Code):

procedure Refresh;
var
  hSysTray: THandle;
begin
  hSysTray := GetSystrayHandle;
  SendMessage(hSysTray, WM_PAINT, 0, 0);
end;

function GetSystrayHandle: THandle;
var
  hTray, hNotify, hSysPager: THandle;
begin
  hTray := FindWindow('Shell_TrayWnd', '');
  if hTray = 0 then
  begin
    Result := hTray;
    exit;
  end;

  hNotify := FindWindowEx(hTray, 0, 'TrayNotifyWnd', '');
  if hNotify = 0 then
  begin
    Result := hNotify;
    exit;
  end;

  hSyspager := FindWindowEx(hNotify, 0, 'SysPager', '');
  if hSyspager = 0 then
  begin
    Result := hSyspager;
    exit;
  end;

  Result := FindWindowEx(hSysPager, 0, 'ToolbarWindow32', 'Notification Area');
end;

But to no avail.

I've even tried with

InvalidateRect()

and still no show.

Any other suggestions?

Answer 1

Take a look at this blog entry: REFRESHING THE TASKBAR NOTIFICATION AREA. I am using this code to refresh the system tray to get rid of orphaned icons and it works perfectly. The blog entry is very informative and gives a great explanation of the steps the author performed to discover his solution.

#define FW(x,y) FindWindowEx(x, NULL, y, L"")

void RefreshTaskbarNotificationArea()
{
    HWND hNotificationArea;
    RECT r;

    GetClientRect(
        hNotificationArea = FindWindowEx(
            FW(FW(FW(NULL, L"Shell_TrayWnd"), L"TrayNotifyWnd"), L"SysPager"),
            NULL,
            L"ToolbarWindow32",
            // L"Notification Area"), // Windows XP
            L"User Promoted Notification Area"), // Windows 7 and up
        &r);

    for (LONG x = 0; x < r.right; x += 5)
        for (LONG y = 0; y < r.bottom; y += 5)
            SendMessage(
                hNotificationArea,
                WM_MOUSEMOVE,
                0,
                (y << 16) + x);
}

Answer 2

Two important details for anyone using Louis's answer (from REFRESHING THE TASKBAR NOTIFICATION AREA) on Windows 7 or Windows 8:

First, as the answer was reflected to show, the window titled "Notification Area" in XP is now titled "User Promoted Notification Area" in Windows 7 (actually probably Vista) and up.

Second, this code does not clear icons that are currently hidden. These are contained in a separate window. Use the original code to refresh visible icons, and the following to refresh hidden icons.

//Hidden icons
GetClientRect(
    hNotificationArea = FindWindowEx(
        FW(NULL, L"NotifyIconOverflowWindow"),
        NULL,
        L"ToolbarWindow32",
        L"Overflow Notification Area"),
    &r);

for (LONG x = 0; x < r.right; x += 5)
    for (LONG y = 0; y < r.bottom; y += 5)
        SendMessage(
            hNotificationArea,
            WM_MOUSEMOVE,
            0,
            (y << 16) + x);

For anyone who just needs a utility to run to accomplish this, rather than code, I built a simple exe with this update: Refresh Notification Area