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Win32 sample WebView2Browser

  • Article

This sample, WebView2Browser, is a web browser built with the Microsoft Edge WebView2 control.

This sample has its own dedicated repo.

  • Sample name: WebView2Browser
  • Repo: WebView2Browser
  • Solution file: WebViewBrowserApp.sln

The WebView2Browser sample app

WebView2Browser is a sample Windows desktop application demonstrating the capabilities of the WebView2 control. The WebView2Browser sample app uses multiple WebView2 instances.

This sample is built as a Win32 Visual Studio 2019 project. It uses C++ and JavaScript in the WebView2 environment.

WebView2Browser shows some of the simplest uses of WebView2, such as creating and navigating a WebView, but also some more complex workflows like using the PostWebMessageAsJson API to communicate across WebView2 controls in separate environments. This is a rich code sample to demonstrate how you can use WebView2 APIs to build your own app.

Step 1: Install a preview channel of Microsoft Edge

Step 2: Install Visual Studio

  1. Install Visual Studio, including C++ support.

The WebView2 Runtime is recommended for the installation. The minimum version is 86.0.622.38.

Step 3: Clone the WebView2Samples repo

Step 4: Open the solution in Visual Studio

  1. Open the solution in Visual Studio 2019. The WebView2 SDK is already included as a NuGet package in the project. If you want to use Visual Studio 2017, change the project's Platform Toolset in Project Properties > Configuration properties > General > Platform Toolset. You might also need to change the Windows SDK to the latest version.

  2. Make the changes listed below, if you're using a Windows version below Windows 10.

Using versions below Windows 10

If you want to build and run the browser in versions of Windows before Windows 10, make the following changes. This is required because of how DPI is handled in Windows 10 vs previous versions of Windows.

  1. If you want to build and run the browser in versions of Windows before Windows 10: In WebViewBrowserApp.cpp, change SetProcessDpiAwarenessContext to SetProcessDPIAware:
int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
                      _In_opt_ HINSTANCE hPrevInstance,
                      _In_ LPWSTR    lpCmdLine,
                      _In_ int       nCmdShow)
{
    UNREFERENCED_PARAMETER(hPrevInstance);
    UNREFERENCED_PARAMETER(lpCmdLine);

    // Call SetProcessDPIAware() instead when using Windows 7 or any version
    // below 1703 (Windows 10).
    SetProcessDpiAwarenessContext(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);

    BrowserWindow::RegisterClass(hInstance);

    // ...
  1. If you want to build and run the browser in versions of Windows before Windows 10: In BrowserWindow.cpp, remove or comment out the following call to GetDpiForWindow:
int BrowserWindow::GetDPIAwareBound(int bound)
{
    // Remove the GetDpiForWindow call when using Windows 7 or any version
    // below 1607 (Windows 10). You will also have to make sure the build
    // directory is clean before building again.
    return (bound * GetDpiForWindow(m_hWnd) / DEFAULT_DPI);
}

Step 5: Build and run the app

  1. Set the target you want to build (such as Debug or Release, targeting x86 or x64).

  2. Build the solution.

  3. Run (or Debug) the app.

  4. Close the app.

Step 6: Update the WebView2 SDK

  • Update the version of the WebView2 SDK, in Visual Studio. To do this, right-click the project and then click Manage NuGet Packages.

Step 7: Build and run the app with updated WebView2 SDK

  • Build and run the app again.

Browser layout

The WebView2Browser sample app uses multiple WebView2 instances.

WebView2Browser has a multi-WebView approach to integrate web content and application UI into a Windows Desktop application. This allows the browser to use standard web technologies (HTML, CSS, JavaScript) to light up the interface but also enables the app to fetch favicons from the web and use IndexedDB for storing favorites and history.

The multi-WebView approach involves using two separate WebView environments (each with its own user data directory): one for the UI WebViews and the other for all content WebViews. UI WebViews (controls and options dropdown list) use the UI environment, while web content WebViews (one per tab) use the content environment.

Browser layout

Features

The WebView2Browser sample provides all the functionalities to make a basic web browser, but there's plenty of room for you to play around.

The WebView2Browser sample implements the following features:

  • Go back/forward
  • Reload page
  • Cancel navigation
  • Multiple tabs
  • History
  • Favorites
  • Search from the address bar
  • Page security status
  • Clearing cache and cookies

WebView2 APIs

WebView2Browser makes use of a handful of the APIs available in WebView2. For the APIs not used here, you can find more about them in the Microsoft Edge WebView2 Reference. The following is a list of the most interesting APIs WebView2Browser uses and the features they enable.

API Features
CreateCoreWebView2EnvironmentWithOptions Used to create the environments for UI and content WebViews. Different user data directories are passed to isolate UI from web content.
ICoreWebView2 There are several WebViews in WebView2Browser and most features make use of members in this interface, the table below shows how they're used.
ICoreWebView2DevToolsProtocolEventReceivedEventHandler Used along with add_DevToolsProtocolEventReceived to listen for CDP security events to update the lock icon in the browser UI.
ICoreWebView2DevToolsProtocolEventReceiver Used along with add_DevToolsProtocolEventReceived to listen for CDP security events to update the lock icon in the browser UI.
ICoreWebView2ExecuteScriptCompletedHandler Used along with ExecuteScript to get the title and favicon from the visited page.
ICoreWebView2FocusChangedEventHandler Used along with add_LostFocus to hide the browser options dropdown list when it loses focus.
ICoreWebView2HistoryChangedEventHandler Used along with add_HistoryChanged to update the navigation buttons in the browser UI.
ICoreWebView2Controller There are several WebViewControllers in WebView2Browser and we fetch the associated WebViews from them.
ICoreWebView2NavigationCompletedEventHandler Used along with add_NavigationCompleted to update the reload button in the browser UI.
ICoreWebView2Settings Used to disable DevTools in the browser UI.
ICoreWebView2SourceChangedEventHandler Used along with add_SourceChanged to update the address bar in the browser UI.
ICoreWebView2WebMessageReceivedEventHandler This is one of the most important APIs to WebView2Browser. Most functionalities involving communication across WebViews use this.
ICoreWebView2 API Features
add_NavigationStarting Used to display the cancel navigation button in the controls WebView.
add_SourceChanged Used to update the address bar.
add_HistoryChanged Used to update go back/forward buttons.
add_NavigationCompleted Used to display the reload button once a navigation completes.
ExecuteScript Used to get the title and favicon of a visited page.
PostWebMessageAsJson Used to communicate WebViews. All messages use JSON to pass parameters needed.
add_WebMessageReceived Used to handle web messages posted to the WebView.
CallDevToolsProtocolMethod Used to enable listening for security events, which will notify of security status changes in a document.
ICoreWebView2Controller API Feature(s)
get_CoreWebView2 Used to get the CoreWebView2 associated with this CoreWebView2Controller.
add_LostFocus Used to hide the options dropdown list when the user clicks away from it.

Implementing the features

The sections below describe how some of the features in WebView2Browser were implemented. You can look at the source code for more details about how everything works here.

Contents:

The basics

Set up the environment, create a WebView

WebView2 allows you to host web content in your Windows app. It exposes the globals CreateCoreWebView2Environment and CreateCoreWebView2EnvironmentWithOptions from which we can create the two separate environments for the browser's UI and content.

    // Get directory for user data. This will be kept separated from the
    // directory for the browser UI data.
    std::wstring userDataDirectory = GetAppDataDirectory();
    userDataDirectory.append(L"\\User Data");

    // Create WebView environment for web content requested by the user. All
    // tabs will be created from this environment and kept isolated from the
    // browser UI. This environment is created first so the UI can request new
    // tabs when it's ready.
    HRESULT hr = CreateCoreWebView2EnvironmentWithOptions(nullptr, userDataDirectory.c_str(),
        L"", Callback<ICoreWebView2CreateCoreWebView2EnvironmentCompletedHandler>(
            [this](HRESULT result, ICoreWebView2Environment* env) -> HRESULT
    {
        RETURN_IF_FAILED(result);

        m_contentEnv = env;
        HRESULT hr = InitUIWebViews();

        if (!SUCCEEDED(hr))
        {
            OutputDebugString(L"UI WebViews environment creation failed\n");
        }

        return hr;
    }).Get());

HRESULT BrowserWindow::InitUIWebViews()
{
    // Get data directory for browser UI data
    std::wstring browserDataDirectory = GetAppDataDirectory();
    browserDataDirectory.append(L"\\Browser Data");

    // Create WebView environment for browser UI. A separate data directory is
    // used to isolate the browser UI from web content requested by the user.
    return CreateCoreWebView2EnvironmentWithOptions(nullptr, browserDataDirectory.c_str(),
        L"", Callback<ICoreWebView2CreateCoreWebView2EnvironmentCompletedHandler>(
            [this](HRESULT result, ICoreWebView2Environment* env) -> HRESULT
    {
        // Environment is ready, create the WebView
        m_uiEnv = env;

        RETURN_IF_FAILED(CreateBrowserControlsWebView());
        RETURN_IF_FAILED(CreateBrowserOptionsWebView());

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

We use the ICoreWebView2CreateCoreWebView2EnvironmentCompletedHandler to create the UI WebViews once the environment is ready.

HRESULT BrowserWindow::CreateBrowserControlsWebView()
{
    return m_uiEnv->CreateCoreWebView2Controller(m_hWnd, Callback<ICoreWebView2CreateCoreWebView2ControllerCompletedHandler>(
        [this](HRESULT result, ICoreWebView2Controller* controller) -> HRESULT
    {
        if (!SUCCEEDED(result))
        {
            OutputDebugString(L"Controls WebView creation failed\n");
            return result;
        }
        // WebView created
        m_controlsController = controller;
        CheckFailure(m_controlsController->get_CoreWebView2(&m_controlsWebView), L"");

        wil::com_ptr<ICoreWebView2Settings> settings;
        RETURN_IF_FAILED(m_controlsWebView->get_Settings(&settings));
        RETURN_IF_FAILED(settings->put_AreDevToolsEnabled(FALSE));

        RETURN_IF_FAILED(m_controlsController->add_ZoomFactorChanged(Callback<ICoreWebView2ZoomFactorChangedEventHandler>(
            [](ICoreWebView2Controller* controller, IUnknown* args) -> HRESULT
        {
            controller->put_ZoomFactor(1.0);
            return S_OK;
        }
        ).Get(), &m_controlsZoomToken));

        RETURN_IF_FAILED(m_controlsWebView->add_WebMessageReceived(m_uiMessageBroker.Get(), &m_controlsUIMessageBrokerToken));
        RETURN_IF_FAILED(ResizeUIWebViews());

        std::wstring controlsPath = GetFullPathFor(L"wvbrowser_ui\\controls_ui\\default.html");
        RETURN_IF_FAILED(m_controlsWebView->Navigate(controlsPath.c_str()));

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

We're setting up a few things here. The ICoreWebView2Settings interface is used to disable DevTools in the WebView powering the browser controls. We're also adding a handler for received web messages. This handler will enable us to do something when the user interacts with the controls in this WebView.

Navigate to web page

You can navigate to a web page by entering its URI in the address bar. When pressing Enter, the controls WebView will post a web message to the host app so it can navigate the active tab to the specified location. Code below shows how the host Win32 application will handle that message.

        case MG_NAVIGATE:
        {
            std::wstring uri(args.at(L"uri").as_string());
            std::wstring browserScheme(L"browser://");

            if (uri.substr(0, browserScheme.size()).compare(browserScheme) == 0)
            {
                // No encoded search URI
                std::wstring path = uri.substr(browserScheme.size());
                if (path.compare(L"favorites") == 0 ||
                    path.compare(L"settings") == 0 ||
                    path.compare(L"history") == 0)
                {
                    std::wstring filePath(L"wvbrowser_ui\\content_ui\\");
                    filePath.append(path);
                    filePath.append(L".html");
                    std::wstring fullPath = GetFullPathFor(filePath.c_str());
                    CheckFailure(m_tabs.at(m_activeTabId)->m_contentWebView->Navigate(fullPath.c_str()), L"Can't navigate to browser page.");
                }
                else
                {
                    OutputDebugString(L"Requested unknown browser page\n");
                }
            }
            else if (!SUCCEEDED(m_tabs.at(m_activeTabId)->m_contentWebView->Navigate(uri.c_str())))
            {
                CheckFailure(m_tabs.at(m_activeTabId)->m_contentWebView->Navigate(args.at(L"encodedSearchURI").as_string().c_str()), L"Can't navigate to requested page.");
            }
        }
        break;

WebView2Browser will check the URI against browser pages (i.e. favorites, settings, history) and navigate to the requested location or use the provided URI to search Bing as a fallback.

Updating the address bar

The address bar is updated every time there is a change in the active tab's document source and along with other controls when switching tabs. Each WebView will fire an event when the state of the document changes, we can use this event to get the new source on updates and forward the change to the controls WebView (we'll also update the go back and go forward buttons).

        // Register event handler for doc state change
        RETURN_IF_FAILED(m_contentWebView->add_SourceChanged(Callback<ICoreWebView2SourceChangedEventHandler>(
            [this, browserWindow](ICoreWebView2* webview, ICoreWebView2SourceChangedEventArgs* args) -> HRESULT
        {
            BrowserWindow::CheckFailure(browserWindow->HandleTabURIUpdate(m_tabId, webview), L"Can't update address bar");

            return S_OK;
        }).Get(), &m_uriUpdateForwarderToken));

HRESULT BrowserWindow::HandleTabURIUpdate(size_t tabId, ICoreWebView2* webview)
{
    wil::unique_cotaskmem_string source;
    RETURN_IF_FAILED(webview->get_Source(&source));

    web::json::value jsonObj = web::json::value::parse(L"{}");
    jsonObj[L"message"] = web::json::value(MG_UPDATE_URI);
    jsonObj[L"args"] = web::json::value::parse(L"{}");
    jsonObj[L"args"][L"tabId"] = web::json::value::number(tabId);
    jsonObj[L"args"][L"uri"] = web::json::value(source.get());

    // ...

    RETURN_IF_FAILED(PostJsonToWebView(jsonObj, m_controlsWebView.Get()));

    return S_OK;
}

HRESULT BrowserWindow::HandleTabHistoryUpdate(size_t tabId, ICoreWebView2* webview)
{
    // ...

    BOOL canGoForward = FALSE;
    RETURN_IF_FAILED(webview->get_CanGoForward(&canGoForward));
    jsonObj[L"args"][L"canGoForward"] = web::json::value::boolean(canGoForward);

    BOOL canGoBack = FALSE;
    RETURN_IF_FAILED(webview->get_CanGoBack(&canGoBack));
    jsonObj[L"args"][L"canGoBack"] = web::json::value::boolean(canGoBack);

    RETURN_IF_FAILED(PostJsonToWebView(jsonObj, m_controlsWebView.Get()));

    return S_OK;
}

We have sent the MG_UPDATE_URI message along with the URI to the controls WebView. Now we want to reflect those changes on the tab state and update the UI if necessary.

        case commands.MG_UPDATE_URI:
            if (isValidTabId(args.tabId)) {
                const tab = tabs.get(args.tabId);
                let previousURI = tab.uri;

                // Update the tab state
                tab.uri = args.uri;
                tab.uriToShow = args.uriToShow;
                tab.canGoBack = args.canGoBack;
                tab.canGoForward = args.canGoForward;

                // If the tab is active, update the controls UI
                if (args.tabId == activeTabId) {
                    updateNavigationUI(message);
                }

                // ...
            }
            break;

Going back, going forward

Each WebView will keep a history for the navigations it has performed so we only need to connect the browser UI with the corresponding methods. If the active tab's WebView can be navigated back/forward, the buttons will post a web message to the host application when clicked.

The JavaScript side:

    document.querySelector('#btn-forward').addEventListener('click', function(e) {
        if (document.getElementById('btn-forward').className === 'btn') {
            var message = {
                message: commands.MG_GO_FORWARD,
                args: {}
            };
            window.chrome.webview.postMessage(message);
        }
    });

    document.querySelector('#btn-back').addEventListener('click', function(e) {
        if (document.getElementById('btn-back').className === 'btn') {
            var message = {
                message: commands.MG_GO_BACK,
                args: {}
            };
            window.chrome.webview.postMessage(message);
        }
    });

The host application side:

        case MG_GO_FORWARD:
        {
            CheckFailure(m_tabs.at(m_activeTabId)->m_contentWebView->GoForward(), L"");
        }
        break;
        case MG_GO_BACK:
        {
            CheckFailure(m_tabs.at(m_activeTabId)->m_contentWebView->GoBack(), L"");
        }
        break;

Reloading, stop navigation

We use the NavigationStarting event fired by a content WebView to update its associated tab loading state in the controls WebView. Similarly, when a WebView fires the NavigationCompleted event, we use that event to instruct the controls WebView to update the tab state. The active tab state in the controls WebView will determine whether to show the reload or the cancel button. Each of those will post a message back to the host application when clicked, so that the WebView for that tab can be reloaded or have its navigation canceled, accordingly.

function reloadActiveTabContent() {
    var message = {
        message: commands.MG_RELOAD,
        args: {}
    };
    window.chrome.webview.postMessage(message);
}

 // ...

    document.querySelector('#btn-reload').addEventListener('click', function(e) {
        var btnReload = document.getElementById('btn-reload');
        if (btnReload.className === 'btn-cancel') {
            var message = {
                message: commands.MG_CANCEL,
                args: {}
            };
            window.chrome.webview.postMessage(message);
        } else if (btnReload.className === 'btn') {
            reloadActiveTabContent();
        }
    });

        case MG_RELOAD:
        {
            CheckFailure(m_tabs.at(m_activeTabId)->m_contentWebView->Reload(), L"");
        }
        break;
        case MG_CANCEL:
        {
            CheckFailure(m_tabs.at(m_activeTabId)->m_contentWebView->CallDevToolsProtocolMethod(L"Page.stopLoading", L"{}", nullptr), L"");
        }

Some interesting features

Communicating the WebViews

We need to communicate the WebViews that power the tabs and UI, so that user interactions in one tab's WebView have the desired effect in the other WebView. WebView2Browser makes use of set of very useful WebView2 APIs for this purpose, including PostWebMessageAsJson, add_WebMessageReceived and ICoreWebView2WebMessageReceivedEventHandler.

On the JavaScript side, we're making use of the window.chrome.webview object exposed to call the postMessage method and add an event lister for received messages.

HRESULT BrowserWindow::CreateBrowserControlsWebView()
{
    return m_uiEnv->CreateCoreWebView2Controller(m_hWnd, Callback<ICoreWebView2CreateCoreWebView2ControllerCompletedHandler>(
        [this](HRESULT result, ICoreWebView2Controller* controller) -> HRESULT
    {
        // ...

        RETURN_IF_FAILED(m_controlsWebView->add_WebMessageReceived(m_uiMessageBroker.Get(), &m_controlsUIMessageBrokerToken));

        // ...

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

HRESULT BrowserWindow::PostJsonToWebView(web::json::value jsonObj, ICoreWebView2* webview)
{
    utility::stringstream_t stream;
    jsonObj.serialize(stream);

    return webview->PostWebMessageAsJson(stream.str().c_str());
}

// ...

HRESULT BrowserWindow::HandleTabNavStarting(size_t tabId, ICoreWebView2* webview)
{
    web::json::value jsonObj = web::json::value::parse(L"{}");
    jsonObj[L"message"] = web::json::value(MG_NAV_STARTING);
    jsonObj[L"args"] = web::json::value::parse(L"{}");
    jsonObj[L"args"][L"tabId"] = web::json::value::number(tabId);

    return PostJsonToWebView(jsonObj, m_controlsWebView.Get());
}

function init() {
    window.chrome.webview.addEventListener('message', messageHandler);
    refreshControls();
    refreshTabs();

    createNewTab(true);
}

// ...

function reloadActiveTabContent() {
    var message = {
        message: commands.MG_RELOAD,
        args: {}
    };
    window.chrome.webview.postMessage(message);
}

Tab handling

A new tab will be created whenever the user clicks on the new tab button to the right of the open tabs. The control's WebView will post a message to the host application to create the WebView for that tab and create an object tracking its state.

function createNewTab(shouldBeActive) {
    const tabId = getNewTabId();

    var message = {
        message: commands.MG_CREATE_TAB,
        args: {
            tabId: parseInt(tabId),
            active: shouldBeActive || false
        }
    };

    window.chrome.webview.postMessage(message);

    tabs.set(parseInt(tabId), {
        title: 'New Tab',
        uri: '',
        uriToShow: '',
        favicon: 'img/favicon.png',
        isFavorite: false,
        isLoading: false,
        canGoBack: false,
        canGoForward: false,
        securityState: 'unknown',
        historyItemId: INVALID_HISTORY_ID
    });

    loadTabUI(tabId);

    if (shouldBeActive) {
        switchToTab(tabId, false);
    }
}

On the host app side, the registered ICoreWebView2WebMessageReceivedEventHandler will catch the message and create the WebView for that tab.

        case MG_CREATE_TAB:
        {
            size_t id = args.at(L"tabId").as_number().to_uint32();
            bool shouldBeActive = args.at(L"active").as_bool();
            std::unique_ptr<Tab> newTab = Tab::CreateNewTab(m_hWnd, m_contentEnv.Get(), id, shouldBeActive);

            std::map<size_t, std::unique_ptr<Tab>>::iterator it = m_tabs.find(id);
            if (it == m_tabs.end())
            {
                m_tabs.insert(std::pair<size_t,std::unique_ptr<Tab>>(id, std::move(newTab)));
            }
            else
            {
                m_tabs.at(id)->m_contentWebView->Close();
                it->second = std::move(newTab);
            }
        }
        break;

std::unique_ptr<Tab> Tab::CreateNewTab(HWND hWnd, ICoreWebView2Environment* env, size_t id, bool shouldBeActive)
{
    std::unique_ptr<Tab> tab = std::make_unique<Tab>();

    tab->m_parentHWnd = hWnd;
    tab->m_tabId = id;
    tab->SetMessageBroker();
    tab->Init(env, shouldBeActive);

    return tab;
}

HRESULT Tab::Init(ICoreWebView2Environment* env, bool shouldBeActive)
{
    return env->CreateCoreWebView2Controller(m_parentHWnd, Callback<ICoreWebView2CreateCoreWebView2ControllerCompletedHandler>(
        [this, shouldBeActive](HRESULT result, ICoreWebView2Controller* controller) -> HRESULT {
        if (!SUCCEEDED(result))
        {
            OutputDebugString(L"Tab WebView creation failed\n");
            return result;
        }
        m_contentController = controller;
        BrowserWindow::CheckFailure(m_contentController->get_CoreWebView2(&m_contentWebView), L"");
        BrowserWindow* browserWindow = reinterpret_cast<BrowserWindow*>(GetWindowLongPtr(m_parentHWnd, GWLP_USERDATA));
        RETURN_IF_FAILED(m_contentWebView->add_WebMessageReceived(m_messageBroker.Get(), &m_messageBrokerToken));

        // Register event handler for history change
        RETURN_IF_FAILED(m_contentWebView->add_HistoryChanged(Callback<ICoreWebView2HistoryChangedEventHandler>(
            [this, browserWindow](ICoreWebView2* webview, IUnknown* args) -> HRESULT
        {
            BrowserWindow::CheckFailure(browserWindow->HandleTabHistoryUpdate(m_tabId, webview), L"Can't update go back/forward buttons.");

            return S_OK;
        }).Get(), &m_historyUpdateForwarderToken));

        // Register event handler for source change
        RETURN_IF_FAILED(m_contentWebView->add_SourceChanged(Callback<ICoreWebView2SourceChangedEventHandler>(
            [this, browserWindow](ICoreWebView2* webview, ICoreWebView2SourceChangedEventArgs* args) -> HRESULT
        {
            BrowserWindow::CheckFailure(browserWindow->HandleTabURIUpdate(m_tabId, webview), L"Can't update address bar");

            return S_OK;
        }).Get(), &m_uriUpdateForwarderToken));

        RETURN_IF_FAILED(m_contentWebView->add_NavigationStarting(Callback<ICoreWebView2NavigationStartingEventHandler>(
            [this, browserWindow](ICoreWebView2* webview, ICoreWebView2NavigationStartingEventArgs* args) -> HRESULT
        {
            BrowserWindow::CheckFailure(browserWindow->HandleTabNavStarting(m_tabId, webview), L"Can't update reload button");

            return S_OK;
        }).Get(), &m_navStartingToken));

        RETURN_IF_FAILED(m_contentWebView->add_NavigationCompleted(Callback<ICoreWebView2NavigationCompletedEventHandler>(
            [this, browserWindow](ICoreWebView2* webview, ICoreWebView2NavigationCompletedEventArgs* args) -> HRESULT
        {
            BrowserWindow::CheckFailure(browserWindow->HandleTabNavCompleted(m_tabId, webview, args), L"Can't update reload button");
            return S_OK;
        }).Get(), &m_navCompletedToken));

        // Handle security state updates

        RETURN_IF_FAILED(m_contentWebView->Navigate(L"https://www.bing.com"));
        browserWindow->HandleTabCreated(m_tabId, shouldBeActive);

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

The tab registers all handlers so it can forward updates to the controls WebView when events fire. The tab is ready and will be shown on the content area of the browser. Clicking on a tab in the controls WebView will post a message to the host application, which will in turn hide the WebView for the previously active tab and show the one for the clicked tab.

HRESULT BrowserWindow::SwitchToTab(size_t tabId)
{
    size_t previousActiveTab = m_activeTabId;

    RETURN_IF_FAILED(m_tabs.at(tabId)->ResizeWebView());
    RETURN_IF_FAILED(m_tabs.at(tabId)->m_contentWebView->put_IsVisible(TRUE));
    m_activeTabId = tabId;

    if (previousActiveTab != INVALID_TAB_ID && previousActiveTab != m_activeTabId)
    {
        RETURN_IF_FAILED(m_tabs.at(previousActiveTab)->m_contentWebView->put_IsVisible(FALSE));
    }

    return S_OK;
}

Updating the security icon

We use the CallDevToolsProtocolMethod to enable listening for security events. Whenever a securityStateChanged event is fired, we will use the new state to update the security icon on the controls WebView.

        // Enable listening for security events to update secure icon
        RETURN_IF_FAILED(m_contentWebView->CallDevToolsProtocolMethod(L"Security.enable", L"{}", nullptr));

        BrowserWindow::CheckFailure(m_contentWebView->GetDevToolsProtocolEventReceiver(L"Security.securityStateChanged", &m_securityStateChangedReceiver), L"");

        // Forward security status updates to browser
        RETURN_IF_FAILED(m_securityStateChangedReceiver->add_DevToolsProtocolEventReceived(Callback<ICoreWebView2DevToolsProtocolEventReceivedEventHandler>(
            [this, browserWindow](ICoreWebView2* webview, ICoreWebView2DevToolsProtocolEventReceivedEventArgs* args) -> HRESULT
        {
            BrowserWindow::CheckFailure(browserWindow->HandleTabSecurityUpdate(m_tabId, webview, args), L"Can't update security icon");
            return S_OK;
        }).Get(), &m_securityUpdateToken));

HRESULT BrowserWindow::HandleTabSecurityUpdate(size_t tabId, ICoreWebView2* webview, ICoreWebView2DevToolsProtocolEventReceivedEventArgs* args)
{
    wil::unique_cotaskmem_string jsonArgs;
    RETURN_IF_FAILED(args->get_ParameterObjectAsJson(&jsonArgs));
    web::json::value securityEvent = web::json::value::parse(jsonArgs.get());

    web::json::value jsonObj = web::json::value::parse(L"{}");
    jsonObj[L"message"] = web::json::value(MG_SECURITY_UPDATE);
    jsonObj[L"args"] = web::json::value::parse(L"{}");
    jsonObj[L"args"][L"tabId"] = web::json::value::number(tabId);
    jsonObj[L"args"][L"state"] = securityEvent.at(L"securityState");

    return PostJsonToWebView(jsonObj, m_controlsWebView.Get());
}

        case commands.MG_SECURITY_UPDATE:
            if (isValidTabId(args.tabId)) {
                const tab = tabs.get(args.tabId);
                tab.securityState = args.state;

                if (args.tabId == activeTabId) {
                    updateNavigationUI(message);
                }
            }
            break;

Populating the history

WebView2Browser uses IndexedDB in the controls WebView to store history items, just an example of how WebView2 enables you to access standard web technologies as you would in the browser. The item for a navigation will be created as soon as the URI is updated. These items are then retrieved by the history UI in a tab making use of window.chrome.postMessage.

In this case, most functionality is implemented using JavaScript on both ends (controls WebView and content WebView loading the UI) so the host application is only acting as a message broker to communicate those ends.

        case commands.MG_UPDATE_URI:
            if (isValidTabId(args.tabId)) {
                // ...

                // Don't add history entry if URI has not changed
                if (tab.uri == previousURI) {
                    break;
                }

                // Filter URIs that should not appear in history
                if (!tab.uri || tab.uri == 'about:blank') {
                    tab.historyItemId = INVALID_HISTORY_ID;
                    break;
                }

                if (tab.uriToShow && tab.uriToShow.substring(0, 10) == 'browser://') {
                    tab.historyItemId = INVALID_HISTORY_ID;
                    break;
                }

                addHistoryItem(historyItemFromTab(args.tabId), (id) => {
                    tab.historyItemId = id;
                });
            }
            break;

function addHistoryItem(item, callback) {
    queryDB((db) => {
        let transaction = db.transaction(['history'], 'readwrite');
        let historyStore = transaction.objectStore('history');

        // Check if an item for this URI exists on this day
        let currentDate = new Date();
        let year = currentDate.getFullYear();
        let month = currentDate.getMonth();
        let date = currentDate.getDate();
        let todayDate = new Date(year, month, date);

        let existingItemsIndex = historyStore.index('stampedURI');
        let lowerBound = [item.uri, todayDate];
        let upperBound = [item.uri, currentDate];
        let range = IDBKeyRange.bound(lowerBound, upperBound);
        let request = existingItemsIndex.openCursor(range);

        request.onsuccess = function(event) {
            let cursor = event.target.result;
            if (cursor) {
                // There's an entry for this URI, update the item
                cursor.value.timestamp = item.timestamp;
                let updateRequest = cursor.update(cursor.value);

                updateRequest.onsuccess = function(event) {
                    if (callback) {
                        callback(event.target.result.primaryKey);
                    }
                };
            } else {
                // No entry for this URI, add item
                let addItemRequest = historyStore.add(item);

                addItemRequest.onsuccess = function(event) {
                    if (callback) {
                        callback(event.target.result);
                    }
                };
            }
        };

    });
}

Handling JSON and URIs

WebView2Browser uses Microsoft's cpprestsdk (Casablanca) to handle all JSON in the C++ side of things. IUri and CreateUri are also used to parse file paths into URIs and can be used to for other URIs as well.

See also