interface ICoreWebView2ExperimentalFrame6

Note

This an experimental API that is shipped with our prerelease SDK. See WebView2 release notes.

interface ICoreWebView2ExperimentalFrame6
  : public IUnknown

This is an extension of the ICoreWebView2Frame interface that supports ScreenCaptureStarting.

Summary

Members	Descriptions
add_ScreenCaptureStarting	Adds an event handler for the ScreenCaptureStarting event.
remove_ScreenCaptureStarting	Removes an event handler previously added with add_ScreenCaptureStarting.

Applies to

Product	Introduced
WebView2 Win32	N/A
WebView2 Win32 Prerelease

Members

add_ScreenCaptureStarting

Adds an event handler for the ScreenCaptureStarting event.

public HRESULT add_ScreenCaptureStarting(ICoreWebView2ExperimentalFrameScreenCaptureStartingEventHandler * eventHandler, EventRegistrationToken * token)

Add an event handler for the ScreenCaptureStarting event. ScreenCaptureStarting is raised when content in an iframe or any of its descendant iframes requests permission to use the Screen Capture API from getDisplayMedia().

This relates to the ScreenCaptureStarting event on the CoreWebView2. Both these events will be raised in the case of an iframe requesting screen capture. The CoreWebView2Frame's event handlers will be invoked before the event handlers on the CoreWebView2. If the Handled property of the ScreenCaptureStartingEventArgs is set to TRUE within theCoreWebView2Frame event handler, then the event will not be raised on the CoreWebView2, and its event handlers will not be invoked.

    m_webView4 = m_webView.try_query<ICoreWebView2_4>();
    if (m_webView4)
    {
        CHECK_FAILURE(m_webView4->add_FrameCreated(
            Callback<ICoreWebView2FrameCreatedEventHandler>(
                [this](
                    ICoreWebView2* sender, ICoreWebView2FrameCreatedEventArgs* args) -> HRESULT
                {
                    wil::com_ptr<ICoreWebView2Frame> webviewFrame;
                    CHECK_FAILURE(args->get_Frame(&webviewFrame));

                    auto frame5 = webviewFrame.try_query<ICoreWebView2Frame5>();

                    UINT32 frameId;
                    frame5->get_FrameId(&frameId);

                    m_screenCaptureFrameIdPermission[frameId] = TRUE;

                    wil::com_ptr<ICoreWebView2Frame2> webviewFrame2 =
                        webviewFrame.try_query<ICoreWebView2Frame2>();
                    if (!webviewFrame2)
                    {
                        return S_OK;
                    }

                    bool cancel_on_frame = false;

                    CHECK_FAILURE(webviewFrame2->add_WebMessageReceived(
                        Microsoft::WRL::Callback<
                            ICoreWebView2FrameWebMessageReceivedEventHandler>(
                            [this, frameId](
                                ICoreWebView2Frame* sender,
                                ICoreWebView2WebMessageReceivedEventArgs* args) -> HRESULT
                            {
                                BOOL cancel = false;

                                wil::unique_cotaskmem_string messageRaw;
                                HRESULT hr = args->TryGetWebMessageAsString(&messageRaw);
                                if (hr == E_INVALIDARG)
                                {
                                    // Was not a string message. Ignore.
                                    return hr;
                                }
                                // Any other problems are fatal.
                                CHECK_FAILURE(hr);
                                std::wstring message = messageRaw.get();

                                if (message == L"EnableScreenCapture")
                                {
                                    cancel = false;
                                }
                                else if (message == L"DisableScreenCapture")
                                {
                                    cancel = true;
                                }
                                else
                                {
                                    // Ignore unrecognized messages, but log for further
                                    // investigation since it suggests a mismatch between the
                                    // web content and the host.
                                    OutputDebugString(
                                        std::wstring(
                                            L"Unexpected message from main page:" + message)
                                            .c_str());
                                }

                                m_screenCaptureFrameIdPermission[frameId] = (cancel == FALSE);

                                return S_OK;
                            })
                            .Get(),
                        nullptr));

                    m_experimentalFrame6 =
                        webviewFrame.try_query<ICoreWebView2ExperimentalFrame6>();

                    m_experimentalFrame6->add_ScreenCaptureStarting(
                        Callback<
                            ICoreWebView2ExperimentalFrameScreenCaptureStartingEventHandler>(
                            [this](
                                ICoreWebView2Frame* sender,
                                ICoreWebView2ExperimentalScreenCaptureStartingEventArgs* args)
                                -> HRESULT
                            {
                                args->put_Handled(TRUE);

                                bool cancel = FALSE;

                                // Get Frame Info
                                wil::com_ptr<ICoreWebView2FrameInfo> frameInfo;
                                CHECK_FAILURE(args->get_OriginalSourceFrameInfo(&frameInfo));

                                wil::com_ptr<ICoreWebView2FrameInfo2> frameInfo2;
                                CHECK_FAILURE(
                                    frameInfo->QueryInterface(IID_PPV_ARGS(&frameInfo2)));

                                // Frame Source
                                wil::unique_cotaskmem_string frameSource;
                                CHECK_FAILURE(frameInfo->get_Source(&frameSource));

                                UINT32 source_frameId;
                                CHECK_FAILURE(frameInfo2->get_FrameId(&source_frameId));

                                cancel =
                                    (m_screenCaptureFrameIdPermission[source_frameId] == FALSE);

                                CHECK_FAILURE(args->put_Cancel(cancel));
                                return S_OK;
                            })
                            .Get(),
                        &m_frameScreenCaptureStartingToken);

                    return S_OK;
                })
                .Get(),
            &m_frameCreatedToken));
    }
    else
    {
        FeatureNotAvailable();
    }

remove_ScreenCaptureStarting

Removes an event handler previously added with add_ScreenCaptureStarting.

public HRESULT remove_ScreenCaptureStarting(EventRegistrationToken token)