private static void RemoveWndProcUsage(HwndHost hwndHost)
{
int refCount = (int) hwndHost.GetValue(WindowHookRefCountProperty);
refCount--;
hwndHost.SetValue(WindowHookRefCountProperty, refCount);
if (refCount == 0)
{
HwndHostExtensionsWindowHook hook = (HwndHostExtensionsWindowHook) hwndHost.GetValue(WindowHookProperty);
hook.Dispose();
hwndHost.ClearValue(WindowHookProperty);
}
}
private static bool TryHookWndProc(HwndHost hwndHost)
{
if (hwndHost.Handle != IntPtr.Zero)
{
// Hook the window messages so we can intercept the
// various messages.
HwndHostExtensionsWindowHook hook = new HwndHostExtensionsWindowHook(hwndHost);
// Keep our hook alive.
hwndHost.SetValue(WindowHookProperty, hook);
return true;
}
else
{
return false;
}
}
private static void AddWndProcUsage(HwndHost hwndHost)
{
int refCount = (int) hwndHost.GetValue(WindowHookRefCountProperty);
refCount++;
hwndHost.SetValue(WindowHookRefCountProperty, refCount);
if(refCount == 1)
{
if (!TryHookWndProc(hwndHost))
{
// Try again later, when the HwndHost is loaded.
hwndHost.Loaded += (s, e) => TryHookWndProc((HwndHost)s);
}
}
}