GeckoFX - WinForms - javascript:print() - winforms

Question

i just created a win form app
with a Gecko.GeckoWebBrowser on it
when i navigate to a page with a anchor that has the href attribute set to
javascript:print() and click on it, the print dialog is displayed, but it turns out that when i hit cancel button on that dialog
the Gecko.GeckoWebBrowser is destroyed , i mean the control receives a WM_DETROY message
any clue of what is could be happen here?
how i can prevent it?
i modified the gecko fx Gecko.GeckoWebBrowser windows procedure and catch and bypass that windows message but it seems that is not helping
btw i am using xulrunner-11.0.en-US.win32 and geckofx-11.dll
regards

Answer 1

From looking at the firefox code, It looks like firefox is sending the WM_DESTROY message.
nsPrintingPromptService::ShowPrintDialog(nsIDOMWindow *parent, nsIWebBrowserPrint *webBrowserPrint, nsIPrintSettings *printSettings)
{
NS_ENSURE_ARG(parent);
HWND hWnd = GetHWNDForDOMWindow(parent);
NS_ASSERTION(hWnd, "Couldn't get native window for PRint Dialog!");
return NativeShowPrintDialog(hWnd, webBrowserPrint, printSettings);
}
nsresult NativeShowPrintDialog(HWND aHWnd,
nsIWebBrowserPrint* aWebBrowserPrint,
nsIPrintSettings* aPrintSettings)
{
PrepareForPrintDialog(aWebBrowserPrint, aPrintSettings);
nsresult rv = ShowNativePrintDialog(aHWnd, aPrintSettings);
if (aHWnd) {
::DestroyWindow(aHWnd);
}
return rv;
}
I'm not sure why it would do this.
Some options to fix this:
turn on "print.always_print_silent"
provide and register your own nsIPrintingPromptService
provide and register your own nsIWindowWatcher service.
The nsIWindowWatcher way looks like the proper way to do this looking at GetHWNDForDOMWindow:
HWND
nsPrintingPromptService::GetHWNDForDOMWindow(nsIDOMWindow *aWindow)
{
nsCOMPtr<nsIWebBrowserChrome> chrome;
HWND hWnd = NULL;
// We might be embedded so check this path first
if (mWatcher) {
nsCOMPtr<nsIDOMWindow> fosterParent;
if (!aWindow)
{ // it will be a dependent window. try to find a foster parent.
mWatcher->GetActiveWindow(getter_AddRefs(fosterParent));
aWindow = fosterParent;
}
mWatcher->GetChromeForWindow(aWindow, getter_AddRefs(chrome));
}
if (chrome) {
nsCOMPtr<nsIEmbeddingSiteWindow> site(do_QueryInterface(chrome));
if (site)
{
HWND w;
site->GetSiteWindow(reinterpret_cast<void **>(&w));
return w;
}
}