interface ICoreWebView2Environment

Note

This reference is no longer being maintained. For the latest API reference, see WebView2 API Reference.

interface ICoreWebView2Environment
  : public IUnknown

This represents the WebView2 Environment.

Summary

Members	Descriptions
add_NewBrowserVersionAvailable	The NewBrowserVersionAvailable event fires when a newer version of the Edge browser is installed and available to use via WebView2.
CreateCoreWebView2Controller	Asynchronously create a new WebView.
CreateWebResourceResponse	Create a new web resource response object.
get_BrowserVersionString	The browser version info of the current ICoreWebView2Environment, including channel name if it is not the stable channel.
remove_NewBrowserVersionAvailable	Remove an event handler previously added with add_NewBrowserVersionAvailable.

WebViews created from an environment run on the Browser process specified with environment parameters and objects created from an environment should be used in the same environment. Using it in different environments are not guaranteed to be compatible and may fail.

Members

add_NewBrowserVersionAvailable

The NewBrowserVersionAvailable event fires when a newer version of the Edge browser is installed and available to use via WebView2.

public HRESULT add_NewBrowserVersionAvailable(ICoreWebView2NewBrowserVersionAvailableEventHandler * eventHandler, EventRegistrationToken * token)

To use the newer version of the browser you must create a new environment and WebView. This event will only be fired for new version from the same Edge channel that the code is running from. When not running with installed Edge, no event will be fired.

Because a user data folder can only be used by one browser process at a time, if you want to use the same user data folder in the WebViews using the new version of the browser, you must close the environment and WebViews that are using the older version of the browser first. Or simply prompt the user to restart the app.

    // After the environment is successfully created,
    // register a handler for the NewBrowserVersionAvailable event.
    // This handler tells when there is a new Edge version available on the machine.
    CHECK_FAILURE(m_webViewEnvironment->add_NewBrowserVersionAvailable(
        Callback<ICoreWebView2NewBrowserVersionAvailableEventHandler>(
            [this](ICoreWebView2Environment* sender, IUnknown* args) -> HRESULT {
                std::wstring message = L"We detected there is a new version for the browser.";
                if (m_webView)
                {
                    message += L"Do you want to restart the app? \n\n";
                    message += L"Click No if you only want to re-create the webviews. \n";
                    message += L"Click Cancel for no action. \n";
                }
                int response = MessageBox(
                    m_mainWindow, message.c_str(), L"New available version",
                    m_webView ? MB_YESNOCANCEL : MB_OK);

                if (response == IDYES)
                {
                    RestartApp();
                }
                else if (response == IDNO)
                {
                    ReinitializeWebViewWithNewBrowser();
                }
                else
                {
                    // do nothing
                }

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

CreateCoreWebView2Controller

Asynchronously create a new WebView.

public HRESULT CreateCoreWebView2Controller(HWND parentWindow, ICoreWebView2CreateCoreWebView2ControllerCompletedHandler * handler)

parentWindow is the HWND in which the WebView should be displayed and from which receive input. The WebView will add a child window to the provided window during WebView creation. Z-order and other things impacted by sibling window order will be affected accordingly.

It is recommended that the application set Application User Model ID for the process or the application window. If none is set, during WebView creation a generated Application User Model ID is set to root window of parentWindow.

// Create or recreate the WebView and its environment.
void AppWindow::InitializeWebView(InitializeWebViewFlags webviewInitFlags)
{
    m_lastUsedInitFlags = webviewInitFlags;
    // To ensure browser switches get applied correctly, we need to close
    // the existing WebView. This will result in a new browser process
    // getting created which will apply the browser switches.
    CloseWebView();

    LPCWSTR subFolder = nullptr;
    m_dcompDevice = nullptr;
    m_wincompHelper = nullptr;
    LPCWSTR additionalBrowserSwitches = nullptr;
    if (webviewInitFlags & kWindowlessDcompVisual)
    {
        HRESULT hr = DCompositionCreateDevice2(nullptr, IID_PPV_ARGS(&m_dcompDevice));
        if (!SUCCEEDED(hr))
        {
            MessageBox(
                m_mainWindow,
                L"Attempting to create WebView using DComp Visual is not supported.\r\n"
                "DComp device creation failed.\r\n"
                "Current OS may not support DComp.",
                L"Create with Windowless DComp Visual Failed", MB_OK);
            return;
        }
    }
    else if (webviewInitFlags & kWindowlessWincompVisual)
    {
        HRESULT hr = CreateWinCompCompositor();
        if (!SUCCEEDED(hr))
        {
            MessageBox(
                m_mainWindow,
                L"Attempting to create WebView using WinComp Visual is not supported.\r\n"
                "WinComp compositor creation failed.\r\n"
                "Current OS may not support WinComp.",
                L"Create with Windowless WinComp Visual Failed", MB_OK);
            return;
        }
    }
    auto options = Microsoft::WRL::Make<CoreWebView2EnvironmentOptions>();
    CHECK_FAILURE(options->put_AdditionalBrowserArguments(additionalBrowserSwitches));
    if(!m_language.empty())
        CHECK_FAILURE(options->put_Language(m_language.c_str()));
    HRESULT hr = CreateCoreWebView2EnvironmentWithOptions(
        subFolder, nullptr, options.Get(),
        Callback<ICoreWebView2CreateCoreWebView2EnvironmentCompletedHandler>(
            this, &AppWindow::OnCreateEnvironmentCompleted)
            .Get());
    if (!SUCCEEDED(hr))
    {
        if (hr == HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND))
        {
            MessageBox(
                m_mainWindow,
                L"Couldn't find Edge installation. "
                "Do you have a version installed that's compatible with this "
                "WebView2 SDK version?",
                nullptr, MB_OK);
        }
        else
        {
            ShowFailure(hr, L"Failed to create webview environment");
        }
    }
}

// This is the callback passed to CreateWebViewEnvironmnetWithDetails.
// Here we simply create the WebView.
HRESULT AppWindow::OnCreateEnvironmentCompleted(
    HRESULT result, ICoreWebView2Environment* environment)
{
    CHECK_FAILURE(result);

    m_webViewEnvironment = environment;

    auto webViewExperimentalEnvironment =
        m_webViewEnvironment.try_query<ICoreWebView2ExperimentalEnvironment>();
    if (webViewExperimentalEnvironment && (m_dcompDevice || m_wincompHelper))
    {
        CHECK_FAILURE(webViewExperimentalEnvironment->CreateCoreWebView2CompositionController(
            m_mainWindow,
            Callback<
                ICoreWebView2ExperimentalCreateCoreWebView2CompositionControllerCompletedHandler>(
                [this](
                    HRESULT result,
                    ICoreWebView2ExperimentalCompositionController* compositionController) -> HRESULT {
                    auto controller =
                        wil::com_ptr<ICoreWebView2ExperimentalCompositionController>(compositionController)
                            .query<ICoreWebView2Controller>();
                    return OnCreateCoreWebView2ControllerCompleted(result, controller.get());
                })
                .Get()));
    }
    else
    {
        CHECK_FAILURE(m_webViewEnvironment->CreateCoreWebView2Controller(
            m_mainWindow, Callback<ICoreWebView2CreateCoreWebView2ControllerCompletedHandler>(
                              this, &AppWindow::OnCreateCoreWebView2ControllerCompleted)
                              .Get()));
    }

    return S_OK;
}

It is recommended that the application handles restart manager messages so that it can be restarted gracefully in the case when the app is using Edge for webview from a certain installation and that installation is being uninstalled. For example, if a user installs Edge from Dev channel and opts to use Edge from that channel for testing the app, and then uninstalls Edge from that channel without closing the app, the app will be restarted to allow uninstallation of the dev channel to succeed.

    case WM_QUERYENDSESSION:
    {
        // yes, we can shut down
        // Register how we might be restarted
        RegisterApplicationRestart(L"--restore", RESTART_NO_CRASH | RESTART_NO_HANG);
        *result = TRUE;
        return true;
    }
    break;
    case WM_ENDSESSION:
    {
        if (wParam == TRUE)
        {
            // save app state and exit.
            PostQuitMessage(0);
            return true;
        }
    }
    break;

When the application retries CreateCoreWebView2Controller upon failure, it is recommended that the application restarts from creating a new WebView2 Environment. If an Edge update happens, the version associated with a WebView2 Environment could have been removed and causing the object to no longer work. Creating a new WebView2 Environment will work as it uses the latest version.

WebView creation will fail if there is already a running instance using the same user data folder, and the Environment objects have different EnvironmentOptions. For example, if there is already a WebView created with one language, trying to create a WebView with a different language using the same user data folder will fail.

CreateWebResourceResponse

Create a new web resource response object.

public HRESULT CreateWebResourceResponse(IStream * content, int statusCode, LPCWSTR reasonPhrase, LPCWSTR headers, ICoreWebView2WebResourceResponse ** response)

The headers is the raw response header string delimited by newline. It's also possible to create this object with empty headers string and then use the ICoreWebView2HttpResponseHeaders to construct the headers line by line. For information on other parameters see ICoreWebView2WebResourceResponse.

        if (m_blockImages)
        {
            m_webView->AddWebResourceRequestedFilter(L"*", COREWEBVIEW2_WEB_RESOURCE_CONTEXT_IMAGE);
            CHECK_FAILURE(m_webView->add_WebResourceRequested(
                Callback<ICoreWebView2WebResourceRequestedEventHandler>(
                    [this](
                        ICoreWebView2* sender,
                        ICoreWebView2WebResourceRequestedEventArgs* args) {
                        COREWEBVIEW2_WEB_RESOURCE_CONTEXT resourceContext;
                        CHECK_FAILURE(
                            args->get_ResourceContext(&resourceContext));
                        // Ensure that the type is image
                        if (resourceContext != COREWEBVIEW2_WEB_RESOURCE_CONTEXT_IMAGE)
                        {
                            return E_INVALIDARG;
                        }
                        // Override the response with an empty one to block the image.
                        // If put_Response is not called, the request will continue as normal.
                        wil::com_ptr<ICoreWebView2WebResourceResponse> response;
                        CHECK_FAILURE(m_webViewEnvironment->CreateWebResourceResponse(
                            nullptr, 403 /*NoContent*/, L"Blocked", L"", &response));
                        CHECK_FAILURE(args->put_Response(response.get()));
                        return S_OK;
                    })
                    .Get(),
                &m_webResourceRequestedTokenForImageBlocking));
        }
        else
        {
            CHECK_FAILURE(m_webView->remove_WebResourceRequested(
                m_webResourceRequestedTokenForImageBlocking));
        }

get_BrowserVersionString

The browser version info of the current ICoreWebView2Environment, including channel name if it is not the stable channel.

public HRESULT get_BrowserVersionString(LPWSTR * versionInfo)

This matches the format of the GetAvailableCoreWebView2BrowserVersionString API. Channel names are 'beta', 'dev', and 'canary'.

        wil::unique_cotaskmem_string version_info;
        m_webViewEnvironment->get_BrowserVersionString(&version_info);
        MessageBox(
            m_mainWindow, version_info.get(), L"Browser Version Info After WebView Creation",
            MB_OK);

remove_NewBrowserVersionAvailable

Remove an event handler previously added with add_NewBrowserVersionAvailable.

public HRESULT remove_NewBrowserVersionAvailable(EventRegistrationToken token)