{"id":109352,"date":"2024-02-02T07:00:00","date_gmt":"2024-02-02T15:00:00","guid":{"rendered":"https:\/\/devblogs.microsoft.com\/oldnewthing\/?p=109352"},"modified":"2024-02-02T11:13:11","modified_gmt":"2024-02-02T19:13:11","slug":"20240202-00","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/oldnewthing\/20240202-00\/?p=109352","title":{"rendered":"The case of the invalid parameter error from Measure­Override<\/CODE>"},"content":{"rendered":"

A customer had a crash with the following stack:<\/p>\n

KERNELBASE!RaiseFailFastException+0x152\r\ncombase!RoFailFastWithErrorContextInternal2+0x4d9\r\nWindows_UI_Xaml!DirectUI::ErrorHelper::ProcessUnhandledError+0xf4\r\nWindows_UI_Xaml!DirectUI::ErrorHelper::ReportUnhandledError+0xf1\r\nWindows_UI_Xaml!AgCoreCallbacks::ReportUnhandledError+0x7\r\nWindows_UI_Xaml!CFxCallbacks::Error_ReportUnhandledError+0x7\r\nWindows_UI_Xaml!CCoreServices::ReportUnhandledError+0x7\r\nWindows_UI_Xaml!CXcpDispatcher::Tick+0x2e6c59\r\nWindows_UI_Xaml!CXcpDispatcher::OnReentrancyProtectedWindowMessage+0x40\r\nWindows_UI_Xaml!CXcpDispatcher::ProcessMessage+0xec\r\nWindows_UI_Xaml!CXcpDispatcher::WindowProc+0x95\r\nWindows_UI_Xaml!CDeferredInvoke::DispatchQueuedMessage+0x9a\r\nWindows_UI_Xaml!CXcpDispatcher::MessageTimerCallback+0x13\r\nWindows_UI_Xaml!CXcpDispatcher::MessageTimerCallbackStatic+0x1c\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::TimeoutHandler::ImportAdapter$::\r\n    __l2::<lambda_654db17c35df07198786f0867aa10de6>::operator()+0x1f\r\nCoreMessaging!CFlat::SehSafe::Execute<\r\n    <lambda_654db17c35df07198786f0867aa10de6> >+0x2c\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::TimeoutHandler::ImportAdapter$+0xb1\r\nCoreMessaging!CFlat::DelegateImpl<Microsoft::CoreUI::Dispatch::TimeoutHandler,0,\r\n    void __cdecl(void),long __cdecl(void *),0>::Invoke+0x22\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::Timeout::CallHandler+0x3c\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::TimeoutManager::Callback_OnDispatch+0x21e\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::Dispatcher::Callback_DispatchNextItem+0x1b3\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::Dispatcher::Callback_DispatchLoop+0x240\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::EventLoop::Callback_RunCoreLoop+0x36f\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::UserAdapter::DrainCoreMessagingQueue+0x178\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::UserAdapter::OnUserDispatch+0x1f3\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::UserAdapter::OnUserDispatchRaw+0x6d\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::UserAdapter::DoWork+0x206\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::UserAdapter::WindowProc+0x14c\r\nuser32!UserCallWinProcCheckWow+0x2d1\r\nuser32!DispatchClientMessage+0x9c\r\nuser32!__fnDWORD+0x3d\r\nntdll!KiUserCallbackDispatcherContinue\r\nwin32u!ZwUserPeekMessage+0x14\r\nuser32!_PeekMessage+0x3f\r\nuser32!PeekMessageW+0x9c\r\ncontoso!MainWindow::_MessageLoop+0x86\r\ncontoso!MainWindow::MainThreadProc+0x60\r\nkernel32!BaseThreadInitThunk+0x1d\r\nntdll!RtlUserThreadStart+0x28\r\n<\/pre>\n
This stack breaks down into three sections.<\/p>\n\n\n\n\n\n
\n
KERNELBASE!RaiseFailFastException+0x152\r\ncombase!RoFailFastWithErrorContextInternal2+0x4d9\r\nWindows_UI_Xaml!DirectUI::ErrorHelper::ProcessUnhandledError+0xf4\r\nWindows_UI_Xaml!blah blah blah\r\nWindows_UI_Xaml!CXcpDispatcher::WindowProc+0x95\r\nWindows_UI_Xaml!CDeferredInvoke::DispatchQueuedMessage+0x9a\r\nWindows_UI_Xaml!CXcpDispatcher::MessageTimerCallback+0x13\r\nWindows_UI_Xaml!CXcpDispatcher::MessageTimerCallbackStatic+0x1c\r\n<\/pre>\n
XAML<\/div>\n<\/td>\n<\/tr>\n
\n
CoreMessaging!blah blah blah\r\nuser32!blah blah blah\r\n<\/pre>\n
Message dispatch infrastructure<\/div>\n<\/td>\n<\/tr>\n
\n
contoso!MainWindow::MessageLoop+0x86\r\ncontoso!MainWindow::MainThreadProc+0x60\r\nkernel32!BaseThreadInitThunk+0x1d\r\nntdll!RtlUserThreadStart+0x28\r\n<\/pre>\n
Application message loop<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
At the bottom of the stack is the application’s message loop. The message loop calls into the message dispatch infrastructure, which triggered a call into XAML. XAML processed the message, which told it to Report\u00adUnhandled\u00adError<\/code>, so it reported the error to the application before failing fast.<\/p>\n
There isn’t really anything to see from this stack. XAML is reporting an error that occurred some time ago. But the stack for that error is still recorded: You can use the !pde.dse<\/code> extension to d<\/u>ump the s<\/u>towed e<\/u>xceptions.<\/p>\n
The convention in the Windows Runtime is that when code is about to return a COM error (which is the ABI representation of a language exception), it first calls Ro\u00adOriginate\u00adError<\/code> to report the error to the COM infrastructure, which records the error and a stack trace and attaches it to the thread. We saw this earlier when we discussed  the difference between throwing a winrt::hresult_error<\/code> and using winrt::throw_hresult<\/code><\/a>.<\/p>\n
When you ask to dump the stowed exceptions, this digs back into COM’s bookkeeping and pulls out all of the exceptions that are being tracked by the current thread, most recent first.<\/p>\n
 <\/p>\n
In this case, we get eight such exceptions. The most recent one is this horrible stack, which we break down into pieces:<\/p>\n\n\n\n\n\n
\n
contoso!winrt::hresult_error::hresult_error+0x143\r\ncontoso!winrt::hresult_invalid_argument::hresult_invalid_argument+0x14\r\ncontoso!winrt::throw_hresult+0xb9\r\ncontoso!winrt::impl::consume_Windows_UI_Xaml_IFrameworkElementOverrides\r\n    <winrt::Windows::UI::Xaml::IFrameworkElementOverrides>::MeasureOverride+0x3b\r\ncontoso!winrt::impl::produce<winrt::Contoso::implementation::ContosoFrame,\r\n    winrt::Windows::UI::Xaml::IFrameworkElementOverrides>::MeasureOverride+0xa9\r\n<\/pre>\n
App rethrows error<\/div>\n<\/td>\n<\/tr>\n
\n
Windows_UI_Xaml!DirectUI::FrameworkElementGenerated::MeasureOverrideProtected+0xc8\r\nWindows_UI_Xaml!DirectUI::FrameworkElement::MeasureOverrideFromCore+0xf5\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x49a\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CGrid::MeasureOverride+0x11a\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CCanvas::MeasureOverride+0xa0\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CXamlIslandRoot::MeasureOverride+0x71\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CXamlIslandRootCollection::MeasureOverride+0xb6\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CRootVisual::MeasureOverride+0x64\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CLayoutManager::UpdateLayout+0x15a\r\nWindows_UI_Xaml!CCoreServices::NWDrawTree+0x246\r\nWindows_UI_Xaml!CCoreServices::NWDrawMainTree+0xc2\r\nWindows_UI_Xaml!CWindowRenderTarget::Draw+0x71\r\nWindows_UI_Xaml!CXcpBrowserHost::OnTick+0xbc\r\nWindows_UI_Xaml!CXcpDispatcher::Tick+0xa1\r\nWindows_UI_Xaml!CXcpDispatcher::OnReentrancyProtectedWindowMessage+0x40\r\nWindows_UI_Xaml!CXcpDispatcher::ProcessMessage+0xea\r\nWindows_UI_Xaml!CXcpDispatcher::WindowProc+0x95\r\nWindows_UI_Xaml!CDeferredInvoke::DispatchQueuedMessage+0x9a\r\nWindows_UI_Xaml!CXcpDispatcher::MessageTimerCallbackStatic+0x1c\r\n<\/pre>\n
XAML layout
\n(recursive algorithm)<\/div>\n<\/td>\n<\/tr>\n
\n
CoreMessaging!CFlat::SehSafe::Execute<\r\n    <lambda_654db17c35df07198786f0867aa10de6> >+0x2c\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::TimeoutHandler::ImportAdapter$+0xb1\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::TimeoutManager::Callback_OnDispatch+0x21e\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::EventLoop::Callback_RunCoreLoop+0x36f\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::UserAdapter::OnUserDispatch+0x1f3\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::UserAdapter::DoWork+0x206\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::UserAdapter::WindowProc+0x17f\r\nuser32!UserCallWinProcCheckWow+0x4ef\r\nuser32!DispatchClientMessage+0x9c\r\nuser32!__fnDWORD+0x3a\r\nntdll!KiUserCallbackDispatcherContinue+0x0\r\nwin32u!ZwUserPeekMessage+0x14\r\nuser32!_PeekMessage+0xb6\r\nuser32!PeekMessageW+0x146\r\ncontoso!MainWindow::MessageLoop+0x86\r\ncontoso!MainWindow::MainThreadProc+0x60\r\nkernel32!BaseThreadInitThunk+0x14\r\nntdll!RtlUserThreadStart+0x28\r\n<\/pre>\n
Message dispatch<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
Reading from the bottom up lets us see what happened, in chronological order.<\/p>\n
Our message pump dispatched a message that caused XAML to perform a Draw()<\/code> operation. This triggers a NWDrawTree()<\/code>, which in turn forces a recalculation of layout: Update\u00adLayout()<\/code>. This layout happens by measuring a bunch of stuff, which is done recursively down the tree. Eventually, we get to the ContosoFrame<\/code>‘s custom Measure\u00adOverride<\/code> method, and that’s where the exception occurred: On a call to IFramework\u00adElement\u00adOverrides::Measure\u00adOverride<\/code>:<\/p>\n
winrt::Size ContosoFrame::MeasureOverride(winrt::Size availableSize)\r\n{\r\n    m_availableWidth = availableSize.Width;\r\n    UpdateOverflowItems();\r\n\r\n    \/\/ Invalid parameter on the next line.\r\n    auto result = base_type::MeasureOverride(availableSize);\r\n    EnableAnimations();\r\n    return result;\r\n}\r\n<\/pre>\n
Presumably, the availableSize<\/code> was a valid parameter at the time XAML called into Measure\u00adOverride<\/code>, so we must have done something in Update\u00adOverflow\u00adItems()<\/code> that caused the parameter to become invalid. But the customer couldn’t find anything in Update\u00adOverflow\u00adItems()<\/code> that could cause layout to go bad in such a way that availableSize<\/code> changed from a valid parameter to an invalid one.<\/p>\n
Let’s go back and look at the failure again.<\/p>\n
The call to the base class’s Measure\u00adOverride<\/code> resulted in E_INVALID\u00adARG<\/code>, but there are other stowed exceptions, too.<\/p>\n
Stowed Exception #2 @ 0x000000000a3c9b98\r\n0x80070057 (FACILITY_WIN32 - Win32 Undecorated Error Codes):\r\n    E_INVALIDARG - One or more arguments are not valid\r\n\r\nMicrosoft_UI_Xaml!winrt::hresult_error::hresult_error+0x120\r\nMicrosoft_UI_Xaml!winrt::hresult_invalid_argument::hresult_invalid_argument+0x14\r\nMicrosoft_UI_Xaml!winrt::throw_hresult+0xcd\r\nMicrosoft_UI_Xaml!ItemsRepeater::MeasureOverride+0x9aa\r\nMicrosoft_UI_Xaml!winrt::impl::produce<ItemsRepeater,\r\n    winrt::Windows::UI::Xaml::IFrameworkElementOverrides>::MeasureOverride+0x5b\r\nWindows_UI_Xaml!DirectUI::FrameworkElementGenerated::MeasureOverrideProtected+0xc8\r\nWindows_UI_Xaml!DirectUI::FrameworkElement::MeasureOverrideFromCore+0xf5\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x49a\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CGrid::MeasureOverride+0x11a\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CControl::MeasureOverride+0x36\r\nWindows_UI_Xaml!DirectUI::FrameworkElement::MeasureOverrideImpl+0x68\r\nWindows_UI_Xaml!DirectUI::FrameworkElementGenerated::MeasureOverride+0x67\r\ncontoso!winrt::impl::consume_Windows_UI_Xaml_IFrameworkElementOverrides\r\n    <winrt::Windows::UI::Xaml::IFrameworkElementOverrides>::MeasureOverride+027\r\ncontoso!winrt::impl::produce<winrt::Contoso::implementation::ContosoFrame,\r\n    winrt::Windows::UI::Xaml::IFrameworkElementOverrides>::MeasureOverride+0xa9\r\nWindows_UI_Xaml!DirectUI::FrameworkElementGenerated::MeasureOverrideProtected+0xc8\r\nWindows_UI_Xaml!DirectUI::FrameworkElement::MeasureOverrideFromCore+0xf5\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x49a\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CGrid::MeasureOverride+0x11a\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CCanvas::MeasureOverride+0xa0\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CXamlIslandRoot::MeasureOverride+0x71\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CXamlIslandRootCollection::MeasureOverride+0xb6\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CRootVisual::MeasureOverride+0x64\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CLayoutManager::UpdateLayout+0x15a\r\nWindows_UI_Xaml!CCoreServices::NWDrawTree+0x246\r\nWindows_UI_Xaml!CCoreServices::NWDrawMainTree+0xc2\r\nWindows_UI_Xaml!CWindowRenderTarget::Draw+0x71\r\nWindows_UI_Xaml!CXcpBrowserHost::OnTick+0xbc\r\nWindows_UI_Xaml!CXcpDispatcher::Tick+0xa1\r\nWindows_UI_Xaml!CXcpDispatcher::OnReentrancyProtectedWindowMessage+0x40\r\nWindows_UI_Xaml!CXcpDispatcher::ProcessMessage+0xea\r\nWindows_UI_Xaml!CXcpDispatcher::WindowProc+0x95\r\nWindows_UI_Xaml!CDeferredInvoke::DispatchQueuedMessage+0x9a\r\nWindows_UI_Xaml!CXcpDispatcher::MessageTimerCallbackStatic+0x1c\r\nCoreMessaging!CFlat::SehSafe::Execute<\r\n    <lambda_654db17c35df07198786f0867aa10de6> >+0x2c\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::TimeoutHandler::ImportAdapter$+0xb1\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::TimeoutManager::Callback_OnDispatch+0x21e\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::EventLoop::Callback_RunCoreLoop+0x36f\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::UserAdapter::OnUserDispatch+0x1f3\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::UserAdapter::DoWork+0x206\r\nCoreMessaging!Microsoft::CoreUI::Dispatch::UserAdapter::WindowProc+0x17f\r\nuser32!UserCallWinProcCheckWow+0x4ef\r\nuser32!DispatchClientMessage+0x9c\r\nuser32!__fnDWORD+0x3a\r\nntdll!KiUserCallbackDispatcherContinue+0x0\r\nwin32u!ZwUserPeekMessage+0x14\r\nuser32!_PeekMessage+0xb6\r\nuser32!PeekMessageW+0x146\r\ncontoso!MainWindow::MessageLoop+0x86\r\ncontoso!MainWidow::MainThreadProc+0x60\r\nkernel32!BaseThreadInitThunk+0x14\r\nntdll!RtlUserThreadStart+0x28\r\n<\/pre>\n
This should look very familiar: This stowed exception has the same exception code, and the bottom part of the stack is the same. The top is a little deeper than the first stack, though:<\/p>\n\n\n\n\n\n\n\n\n\n\n
\u00a0<\/td>\nStowed Exception #2<\/td>\n<\/tr>\n
 <\/td>\n\n
\u00a0<\/div>\n
Microsoft_UI_Xaml!winrt::hresult_error::hresult_error+0x120\r\nMicrosoft_UI_Xaml!winrt::hresult_invalid_argument::hresult_invalid_argument+0x14\r\nMicrosoft_UI_Xaml!winrt::throw_hresult+0xcd\r\nMicrosoft_UI_Xaml!ItemsRepeater::MeasureOverride+0x9aa\r\nMicrosoft_UI_Xaml!winrt::impl::produce<ItemsRepeater,\r\n    winrt::Windows::UI::Xaml::IFrameworkElementOverrides>::MeasureOverride+0x5b\r\nWindows_UI_Xaml!DirectUI::FrameworkElementGenerated::\r\n    MeasureOverrideProtected+0xc8\r\nWindows_UI_Xaml!DirectUI::FrameworkElement::MeasureOverrideFromCore+0xf5\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x49a\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CGrid::MeasureOverride+0x11a\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CControl::MeasureOverride+0x36\r\nWindows_UI_Xaml!DirectUI::FrameworkElement::MeasureOverrideImpl+0x68\r\nWindows_UI_Xaml!DirectUI::FrameworkElementGenerated::MeasureOverride+0x67\r\ncontoso!winrt::impl::consume_Windows_UI_Xaml_IFrameworkElementOverrides\r\n    <winrt::Windows::UI::Xaml::IFrameworkElementOverrides>::MeasureOverride+027\r\n<\/pre>\n<\/td>\n<\/tr>\n
\u00a0<\/td>\n<\/tr>\n
Stowed Exception #1<\/td>\n\u00a0<\/td>\n<\/tr>\n
\n
\u00a0<\/div>\n
contoso!winrt::hresult_error::hresult_error+0x143\r\ncontoso!winrt::hresult_invalid_argument::hresult_invalid_argument+0x14\r\ncontoso!winrt::throw_hresult+0xb9\r\ncontoso!winrt::impl::consume_Windows_UI_Xaml_IFrameworkElementOverrides\r\n    <winrt::Windows::UI::Xaml::IFrameworkElementOverrides>::MeasureOverride+0x3b\r\n<\/pre>\n<\/td>\n
\u00a0<\/td>\n<\/tr>\n
\u00a0<\/td>\n<\/tr>\n
Common portion<\/td>\n<\/tr>\n
\n
\u00a0<\/div>\n
contoso!winrt::impl::produce<winrt::Contoso::implementation::ContosoFrame,\r\n    winrt::Windows::UI::Xaml::IFrameworkElementOverrides>::MeasureOverride+0xa9\r\nWindows_UI_Xaml!DirectUI::FrameworkElementGenerated::MeasureOverrideProtected+0xc8\r\nWindows_UI_Xaml!DirectUI::FrameworkElement::MeasureOverrideFromCore+0xf5\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x49a\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\nWindows_UI_Xaml!CGrid::MeasureOverride+0x11a\r\nWindows_UI_Xaml!CFrameworkElement::MeasureCore+0x220\r\nWindows_UI_Xaml!CUIElement::MeasureInternal+0x1b8\r\nWindows_UI_Xaml!CUIElement::Measure+0x513\r\n\u22ee\r\n<\/pre>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
What we’re seeing here is a cascade failure.<\/p>\n
The stowed exceptions are reported in reverse chronological order (most recent first), so what happened is that the Items\u00adRepeater::Measure\u00adOverride<\/code> returned E_INVALID\u00adARG<\/code>, which C++\/WinRT turned into an exception, causing it to be thrown from Contoso\u00adFrame<\/code>, which is then caught by C++\/WinRT at the ABI boundary and converted back to E_INVALID\u00adARG<\/code> for Measure\u00adOverride\u00adProtected<\/code>.<\/p>\n
We are therefore interested in the root cause of this exception, not all the places where the error is detected and converted to an exception, and then converted from an exception back to an HRESULT<\/code>.<\/p>\n
Going down the list of stowed exceptions takes us backward in time, closer to the origin. But be careful not to go too far and start investigating some other exception. Go back only until the new stowed exception gives you more information than the previous one. In our case, that takes us to stowed exception number 8.<\/p>\n
Stowed Exception #8 @ 0x000000002639f118\r\n0x80070057 (FACILITY_WIN32 - Win32 Undecorated Error Codes):\r\n    E_INVALIDARG - One or more arguments are not valid\r\n\r\ncombase!RoOriginateLanguageException+0x54\r\ncontoso!winrt::hresult_error::originate+0x6f\r\ncontoso!winrt::hresult_error::hresult_error+0x1de\r\ncontoso!winrt::hresult_invalid_argument::hresult_invalid_argument+0x14\r\ncontoso!winrt::throw_hresult+0xb9\r\ncontoso!winrt::throw_last_error+0x23\r\ncontoso!FormatString+0xcb\r\ncontoso!winrt::Contoso::implementation::ContosoListItemViewModel::HelpText+0x401\r\ncontoso!winrt::impl::produce<TaskListItemViewModel>::get_HelpText+0x24\r\ncontoso!winrt::impl::consume_IApplication<>::Resources+0x38\r\ncontoso!winrt::Contoso::implementation::FrameResourcesT<>::\r\n    FrameResources_obj96_Bindings::Update_+0xf4\r\ncontoso!winrt::Contoso::implementation::FrameResourcesT<>::\r\n    FrameResources_obj96_Bindings::ProcessBindings+0x122\r\ncontoso!winrt::MainWindow::implementation::XamlBindings::ProcessBindings+0x1f\r\ncontoso!winrt::impl::produce<XamlBindings>::ProcessBindings+0x44\r\nMicrosoft_UI_Xaml!ViewManager::GetElementFromElementFactory+0x315\r\nMicrosoft_UI_Xaml!ViewManager::GetElement+0x1bc\r\nMicrosoft_UI_Xaml!RepeaterLayoutContext::GetOrCreateElementAtCore+0x90\r\nMicrosoft_UI_Xaml!winrt::impl::produce<VirtualizingLayoutContext>::\r\n    GetOrCreateElementAtCore+0x49\r\nMicrosoft_UI_Xaml!winrt::impl::consume_IVirtualizingLayoutContextOverrides<>::\r\n    GetOrCreateElementAtCore+0x44\r\nMicrosoft_UI_Xaml!VirtualizingLayoutContext::GetOrCreateElementAt+0x8e\r\nMicrosoft_UI_Xaml!winrt::impl::produce<VirtualizingLayoutContext>::\r\n    GetOrCreateElementAt+0x22\r\ncontoso!winrt::impl::consume_IVirtualizingLayoutContext<>::\r\n    GetOrCreateElementAt+0x3e\r\ncontoso!winrt::Contoso::implementation::FrameLayout::MeasureOverride+0xba\r\ncontoso!winrt::impl::produce<FrameLayout>::MeasureOverride+0x3c\r\n...\r\n<\/pre>\n
Okay, now we are getting somewhere.<\/p>\n
The “invalid argument” exception was thrown from the FormatString<\/code> function:<\/p>\n
inline winrt::hstring FormatString(const PCWSTR format, ...)\r\n{\r\n    va_list ap;\r\n    va_start(ap, format);\r\n\r\n    wchar_t strBuffer[512];\r\n    if (FormatMessage(FORMAT_MESSAGE_FROM_STRING, format, 0, 0,\r\n            strBuffer, ARRAYSIZE(strBuffer), &ap) == 0)\r\n    {\r\n        winrt::throw_last_error(); \/\/ <<< thrown here\r\n    }\r\n\r\n    return winrt::hstring(strBuffer);\r\n}\r\n<\/pre>\n
Aha, the problem is that Format\u00adMessage<\/code> itself failed with E_INVALID\u00adARG<\/code>.\u00b9<\/p>\n
What would cause Format\u00adMessage<\/code> to fail with E_INVALID\u00adARG<\/code>? All of the arguments look good.<\/p>\n
Well, except that the format string might be invalid.<\/p>\n
The Contoso\u00adList\u00adItem\u00adView\u00adModel::\u00adHelpText<\/code> method is formatting this string:<\/p>\n
hstring preformattedString = viewServices->GetString(L\"ProgressStateText\");\r\nappendState(FormatString(preformattedString.c_str(), formattedValue.c_str()));\r\n<\/pre>\n
The Progress\u00adState\u00adText<\/code> string is<\/p>\n
  <data name=\"ProgressStateText\" xml:space=\"preserve\">\r\n    <value>Operation %1 percent complete<\/value>\r\n    <comment>Accessible text for progress bar<\/comment>\r\n  \r\n<\/pre>\n
The FormatMessage function replaces the %1<\/code> with the percentage amount. But the text is talking about percents. I wonder…<\/p>\n
Hey look, the Italian translation looks suspicious:<\/p>\n
  <data name=\"ProgressStateText\" xml:space=\"preserve\">\r\n    <value>Operazione completata al %1%<\/value>\r\n    <comment>Accessible text for progress bar<\/comment>\r\n  <\/data>\r\n<\/pre>\n
Look at that trailing percent sign. That’s illegal in Format\u00adMessage<\/code>!<\/p>\n
So that’s where the invalid parameter error is coming from. It’s a mistranslated format string that accidentally used a percent sign in a place where percent signs have special meaning.<\/p>\n
This particular string is used for screen readers, and it shouldn’t contain the percent sign at all. That’s why the English version spells it out as “percent”.<\/p>\n
The customer updated the localization comment to emphasize that the word “percent” must be written out in words and that you cannot use the %<\/code> symbol.<\/p>\n
(In case you couldn’t figure it out, the primary goal of today’s investigation was to demonstrate how to use stowed exceptions and specifically how to find the stowed exception that is going to be most helpful in finding the root cause of the problem.)<\/p>\n
\u00b9 Another problem is that the Format\u00adString<\/code> function forgot to call va_end(ap)<\/code> when it was finished with the va_list<\/code>. On most platforms, it’s a nop, but  you still have to call it<\/a>, because you might be unlucky and run on a platform where it actually does something required.<\/p>\n","protected":false},"excerpt":{"rendered":"
Chasing it back to its origin.<\/p>\n","protected":false},"author":1069,"featured_media":111744,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[25],"class_list":["post-109352","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-oldnewthing","tag-code"],"acf":[],"blog_post_summary":"
Chasing it back to its origin.<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/109352","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/users\/1069"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/comments?post=109352"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/109352\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/media\/111744"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/media?parent=109352"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/categories?post=109352"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/tags?post=109352"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}