// The Win32 call to SetFocus does not do it for hwnd that are
// not in the same process as the caller.
// This is implemented here to work around this behavior.
// Fake keystroke are sent to a specific hwnd to force
// Windows to give the focus to that hwnd.
static internal bool SetFocus(IntPtr hwnd)
{
// First Check for ComboLBox
// Because it uses Keystrokes it dismisses the ComboLBox
string className = RealGetWindowClass(hwnd);
if (className == "ComboLBox")
return true;
// If window is currently Disabled or Invisible no need
// to continue
if (!SafeNativeMethods.IsWindowVisible(hwnd) || !SafeNativeMethods.IsWindowEnabled(hwnd))
{
return false;
}
// If already focused, leave as-is. Calling SetForegroundWindow
// on an already focused HWND will remove focus!
if (GetFocusedWindow().Equals(hwnd))
{
return true;
}
// Try calling SetForegroundWindow directly first; it should succeed if we
// already have the focus or have UIAccess
if (UnsafeNativeMethods.SetForegroundWindow(hwnd))
{
return true;
}
// Use the hotkey technique:
// Register a hotkey and send it to ourselves - this gives us the
// input, and allows us to call SetForegroundWindow.
short atom = GlobalAddAtom("FocusHotKey");
if (atom == 0)
{
return false;
}
short vk = 0xB9;
bool gotHotkey = false;
for (int tries = 0; tries < 10; tries++)
{
if (RegisterHotKey(IntPtr.Zero, atom, 0, vk))
{
gotHotkey = true;
break;
}
vk++; // try another key
}
if (gotHotkey)
{
// Get state of modifiers - and temporarilly release them...
bool fShiftDown = (UnsafeNativeMethods.GetAsyncKeyState(UnsafeNativeMethods.VK_SHIFT) & unchecked((int)0x80000000)) != 0;
bool fAltDown = (UnsafeNativeMethods.GetAsyncKeyState(UnsafeNativeMethods.VK_MENU) & unchecked((int)0x80000000)) != 0;
bool fCtrlDown = (UnsafeNativeMethods.GetAsyncKeyState(UnsafeNativeMethods.VK_CONTROL) & unchecked((int)0x80000000)) != 0;
if (fShiftDown)
Input.SendKeyboardInputVK(UnsafeNativeMethods.VK_SHIFT, false);
if (fAltDown)
Input.SendKeyboardInputVK(UnsafeNativeMethods.VK_MENU, false);
if (fCtrlDown)
Input.SendKeyboardInputVK(UnsafeNativeMethods.VK_CONTROL, false);
Input.SendKeyboardInputVK(vk, true);
Input.SendKeyboardInputVK(vk, false);
// Restore release modifier keys...
if (fShiftDown)
Input.SendKeyboardInputVK(UnsafeNativeMethods.VK_SHIFT, true);
if (fAltDown)
Input.SendKeyboardInputVK(UnsafeNativeMethods.VK_MENU, true);
if (fCtrlDown)
Input.SendKeyboardInputVK(UnsafeNativeMethods.VK_CONTROL, true);
// Spin in this message loop until we get the hot key
while (true)
{
// If the hotkey input gets lost (eg due to desktop switch), GetMessage may not return -
// so use MsgWait first so we can timeout if there's no message present instead of blocking.
int result = MsgWaitForMultipleObjects(null, false, 2000, NativeMethods.QS_ALLINPUT);
if (result == NativeMethods.WAIT_FAILED || result == NativeMethods.WAIT_TIMEOUT)
break;
NativeMethods.MSG msg = new NativeMethods.MSG();
if (!GetMessage(ref msg, IntPtr.Zero, 0, 0))
break;
// TranslateMessage() will not set an error to be retrieved with GetLastError,
// so set the pragma to ignore the PERSHARP warning.
// the PERSHARP warning.
#pragma warning suppress 6031, 6523
UnsafeNativeMethods.TranslateMessage(ref msg);
// From the Windows SDK documentation:
// The return value specifies the value returned by the window procedure.
// Although its meaning depends on the message being dispatched, the return
// value generally is ignored.
#pragma warning suppress 6031, 6523
UnsafeNativeMethods.DispatchMessage(ref msg);
if (msg.message == NativeMethods.WM_HOTKEY && (short)msg.wParam == atom)
{
break;
}
}
UnregisterHotKey(IntPtr.Zero, atom);
}
GlobalDeleteAtom(atom);
return UnsafeNativeMethods.SetForegroundWindow(hwnd);
}
// ------------------------------------------------------
//
// Private Methods
//
// ------------------------------------------------------
#region Private Methods
// Infinite loop. Wait for queue items to be processed.
private void WaitForWork()
{
SafeWaitHandle handle = _ev.SafeWaitHandle;
NativeMethods.MSG msg = new NativeMethods.MSG();
while (true)
{
try
{
// pump any messages
while (UnsafeNativeMethods.PeekMessage (ref msg, IntPtr.Zero, 0, 0, NativeMethods.PM_REMOVE))
{
if (msg.message == NativeMethods.WM_QUIT)
{
break;
}
Misc.DispatchMessage(ref msg);
}
// do any work items in the queue
// It's possible items could be enqueued between when we check for the count
// and dequeue but the event is set then and we'll come back into DrainQueue.
// (note: don't use a for loop here because as the counter is incremented
// Count is decremented and we'll only process half the queue)
while (_q.Count > 0)
{
// pull an item off the queue, process, then clear it
QueueItem item = (QueueItem) _q.Dequeue ();
item.Process ();
}
int result = Misc.MsgWaitForMultipleObjects(handle, false, NativeMethods.INFINITE, NativeMethods.QS_ALLINPUT);
if (result == NativeMethods.WAIT_FAILED || result == NativeMethods.WAIT_TIMEOUT)
{
Debug.Assert(false, "MsgWaitForMultipleObjects failed while WaitForWork");
break;
}
}
catch( Exception e )
{
if (Misc.IsCriticalException(e))
throw;
// Might happen when if the hwnd goes away between the peek and the dispatch
}
//
}
}