interface ICoreWebView2DevToolsProtocolEventReceiver

Article
11/18/2024

interface ICoreWebView2DevToolsProtocolEventReceiver
  : public IUnknown

A Receiver is created for a particular DevTools Protocol event and allows you to subscribe and unsubscribe from that event.

Summary

Members	Descriptions
add_DevToolsProtocolEventReceived	Adds an event handler for the `DevToolsProtocolEventReceived` event.
remove_DevToolsProtocolEventReceived	Removes an event handler previously added with `add_DevToolsProtocolEventReceived`.

Obtained from the WebView object using GetDevToolsProtocolEventReceiver.

Applies to

Product	Introduced
WebView2 Win32	0.9.430
WebView2 Win32 Prerelease	0.9.488

Members

add_DevToolsProtocolEventReceived

Adds an event handler for the DevToolsProtocolEventReceived event.

public HRESULT add_DevToolsProtocolEventReceived(ICoreWebView2DevToolsProtocolEventReceivedEventHandler * eventHandler, EventRegistrationToken * token)

Subscribe to a DevToolsProtocol event. The Invoke method of the handler runs whenever the corresponding DevToolsProtocol event runs. Invoke runs with an event args object containing the parameter object of the DevTools Protocol event as a JSON string.

// Prompt the user to name a CDP event, and then subscribe to that event.
void ScriptComponent::SubscribeToCdpEvent()
{
    TextInputDialog dialog(
        m_appWindow->GetMainWindow(),
        L"Subscribe to CDP Event",
        L"CDP event name:",
        L"Enter the name of the CDP event to subscribe to.\r\n"
            L"You may also have to call the \"enable\" method of the\r\n"
            L"event's domain to receive events (for example \"Log.enable\").\r\n",
        L"Log.entryAdded");
    if (dialog.confirmed)
    {
        std::wstring eventName = dialog.input;
        wil::com_ptr<ICoreWebView2DevToolsProtocolEventReceiver> receiver;
        CHECK_FAILURE(
            m_webView->GetDevToolsProtocolEventReceiver(eventName.c_str(), &receiver));

        // If we are already subscribed to this event, unsubscribe first.
        auto preexistingToken = m_devToolsProtocolEventReceivedTokenMap.find(eventName);
        if (preexistingToken != m_devToolsProtocolEventReceivedTokenMap.end())
        {
            CHECK_FAILURE(receiver->remove_DevToolsProtocolEventReceived(
                preexistingToken->second));
        }

        CHECK_FAILURE(receiver->add_DevToolsProtocolEventReceived(
            Callback<ICoreWebView2DevToolsProtocolEventReceivedEventHandler>(
                [this, eventName](
                    ICoreWebView2* sender,
                    ICoreWebView2DevToolsProtocolEventReceivedEventArgs* args) -> HRESULT
                {
                    wil::unique_cotaskmem_string parameterObjectAsJson;
                    CHECK_FAILURE(args->get_ParameterObjectAsJson(&parameterObjectAsJson));
                    std::wstring title = eventName;
                    std::wstring details = parameterObjectAsJson.get();
                    wil::com_ptr<ICoreWebView2DevToolsProtocolEventReceivedEventArgs2> args2;
                    if (SUCCEEDED(args->QueryInterface(IID_PPV_ARGS(&args2))))
                    {
                        wil::unique_cotaskmem_string sessionId;
                        CHECK_FAILURE(args2->get_SessionId(&sessionId));
                        if (sessionId.get() && *sessionId.get())
                        {
                            title = eventName + L" (session:" + sessionId.get() + L")";
                            std::wstring targetId = m_devToolsSessionMap[sessionId.get()];
                            std::wstring targetLabel = m_devToolsTargetLabelMap[targetId];
                            details = L"From " + targetLabel + L" (session:" + sessionId.get() +
                                      L")\r\n" + details;
                        }
                    }
                    m_appWindow->AsyncMessageBox(details, L"CDP Event Fired: " + title);
                    return S_OK;
                })
                .Get(),
            &m_devToolsProtocolEventReceivedTokenMap[eventName]));
    }
}

remove_DevToolsProtocolEventReceived

Removes an event handler previously added with add_DevToolsProtocolEventReceived.

public HRESULT remove_DevToolsProtocolEventReceived(EventRegistrationToken token)

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